# Sahelian heat waves

B. Oueslati (1); B. Pohl (2); V. Moron (3); S. Rome (4)
(1) Centre de Recherches de Climatologie-BIOGEOSCIENCES, Université de Bourgogne, dijon, France; (2) CNRS, Centre de Recherches de Climatologie-BIOGEOSCIENCES, Université de Bourgogne, Dijon, France; (3) Aix-Marseille Université, CEREUM 34 CNRS, France, Geography, Aix-en-Provence, France; (4) Université Grenoble Alpes, LTHE UMR 5564 UJF-CNRS-IRD, Grenoble, France

Large efforts are made to address the heat waves (HW) in developed countries because of their devastating impacts on human health. This interest increased after the intense event over Europe during summer 2003. However, HWs are still understudied over developing countries. This is particularly true in West Africa, and especially in the Sahel, where temperatures recurrently reach critical values, such as during the 2010 HW event. Understanding the Sahelian HWs and associated health risks constitute the main objective of ACASIS, a 4-year project funded by the French Agency ACASIS de la Recherche.

Our work contributes to this project and aims at characterizing the Sahelian HWs and understanding the mechanisms associated with such extreme events.

There is no universal definition of a HW event, since it is highly dependent on the sector of study, health agriculture, transport... and region of interest. In our case, we chose to define a HW as a period of at least 3 consecutive days of extremely high (90th percentile) daily heat index (Rome et al. 2015). This index combines temperature and relative humidity in order to determine the human-perceived equivalent temperature (Steadman, 1979).

Intrinsic properties of Sahelian HW are next analyzed from the Global Summary of the Day (GSOD) synoptic observations and ERA-interim and MERRA reanalyses over 1979-2012 during boreal spring seasons (April-May-June), the hottest period of the year in the Sahel. Reanalyses capture well the observed interannual variability and seasonal cycle at the regional scale, as well as the 1979-2012 increasing linear trend of springtime HW occurrences in Central and Western Sahel.

Reanalyses however overestimate the duration, spatial extent of HW, and underestimate their intensity. For both GSOD and reanalyses, we show that, over the last three decades, Sahelian HWs tend to become more frequent, last longer, cover larger areas and reach higher intensities. The mechanisms associated with HWs are analyzed to assess the respective roles of atmospheric dynamics, radiative and turbulent fluxes, in the establishment of such events.

## P-1113-16

# Changes in the occurrence of cold and heat waves in France toward the end of the century assessed using a stochastic model to downscale climate model simulated temperature

S. Pary (1) ; T. Hoang (1)

(1) EDF/R&D, MFEE, Chatou, France

As cold and heat waves have a major impact on society and economy, these events are widely studied in climate change simulations for different parts of the world. This study may be viewed as another of such studies, but its originality lies in the adopted methodology. The here is to assess changes in cold or heat wave frequency distribution in France at the station, or grid point level in order to avoid any smoothing of the time series which could alter the extremes. Thus 22 robust temperature time-series provided by Meteo- France in the framework of the national research agency project SECIF and designed as SQR (for Reference Daily Time Series in French) are first used to estimate the distributions of cold or heat waves of different durations, from one single day to more than 15 consecutive days. Then a stochastic model for temperature (Parey, et al. 2014), designed to correctly reproduce extreme values, is used to simulate 100 equivalent temperature time series with potentially more severe extremes, so that a distribution of such frequencies can be derived for each station. As the stochastic model simulates the random part of temperature, after removing the deterministic parts (seasonality and trends) of the mean and the standard deviation, these 100 simulations are also

used to reconstruct time-series from each climate model simulation for different periods and greenhouse gas emission scenarios. The climate model biases are corrected by reconstructing the future seasonality as of the observed ones, to which the future changes given by the climate models are added ($Smf = Smo + (Smf - Smp)$; $Svf = Svo \cdot Svmf/Svmp$ where subscripts o is for observation, f for future and p for present). Then, the full climate model non parametric trends in mean and standard deviation are considered. In this way, distributions of the cold or heat waves frequencies can also be obtained for climate model simulations and thus the significance of the changes can be more robustly assessed. The results obtained with two climate models (CNRM-CM5, IPSL-CM5A-MR), two RCP scenarios (RCP4.5 and RCP8.5) and two future periods, the first and second half of the 21st century will be presented.

Parey S., Hoang T.T.H. Dacunha-Castelle D.: Validation of a stochastic temperature generator focusing on extremes, and an example of use for climate change. Climate Research, Vol. 59: 61–75, 2014

## P-1113-17

# Study of Extreme Rainfall Events over Odisha using observation and simulation

S. Payoshni (1); KC. Gouda (2); P. Goswami (3)

(1) CSIR 4PI, BANGALORE, KARNATAKA, India; (2) CSIR 4PI, Cemp, BANGALORE, KARNATAKA, India; (3) CSIR FOURTH PARADIGM INSTITUTE (FORMERLY CSIR CMMACS), Cemp, BANGALORE KARNATAKA, India

The state of Odisha lies in the eastern part of India with a broad coast line of around 480 km. The climate of state fully depends on the Indian summer monsoon and being the coastal state always the disaster due to hydro meteorological events like tropical cyclone, extreme rainfall events (ERE) and flood etc. are important to monitor and model for the real time mitigation and disaster management. In this study first the extreme rainfall analysis is being carried out using the rainfall data from multiple sources like the India Meteorological Department (IMD) daily gridded data, APHRODITE and Tropical Rainfall Measuring Mission (TRMM) data. Firstly the EREs defined with the criteria of a grid point receiving 10cm or more rainfall per 24hour, are counted over the central part of Odisha state domain (18-22.50N, 82-870E) at the daily scale for the period 1951 to 2014. The inter annual variability in the number of ERE over the state are presented and which clearly shows there is an increasing trend in the ERE of about 0.23 events/year. Because there is a positive trend of the EREs in the second part the ERE distributions are being analyzed and clearly indicates there is increase in the ERE over the south, central and eastern part of Odisha while the trend is normal in the northern part. The possible impact of climate change is also quantified. To simulate the ERE the Mesoscale Meteorological Research Institute, Japan Non Hydrostatic Model (NHM) is calibrated for the Odisha region and about 10 such events are simulated and the model is well capable of simulating the EREs before 48-72 hours. Some sensitivity studies also carried out with the model for the optimized configuration of the model for the meso scale forecasting of the EREs over Odisha. This model configuration and the observational study can be used for the investigation of the ERE mechanisms in particular over Odisha region and the medium range forecasts can be useful for different sectors like agriculture planning, water management, disaster management etc. for the state of Odisha

## P-1113-18

# Uses and limits of thermal indices: the case of Sahel

S. Rome (1); V. Moron (2); B. Oueslati (3); B. Pohl (4); B. Fontaine (4); A. Diedhou (5)

(1) Université Grenoble Alpes, LTHE UMR 5564 UJF-CNRS-IRD, Grenoble, France; (2) Aix-Marseille Université, CEREUM 34 CNRS, France, Geography, Aix-en-Provence, France; (3) Centre de Recherches de Climatologie-BIOGEOSCIENCES, Université de Bourgogne, dijon, France; (4) CNRS, Centre de Recherches de Climatologie-BIOGEOSCIENCES, Université de Bourgogne, Dijon, France; (5) Institute of Research for Development (IRD), LTHE - University Grenoble Alpes, Grenoble Cedex 9, France

Our main goal here is to analyse extreme heat waves
(HWs) in the Sahel (13°N-18°N; 16°W-30°E), using different thermal indices. In the ACASIS project funded by the French "Agence Nationale de la Recherche", HWs analyses are characterized for the first time during the hottest season in the Sahel, using the Global Summary of the Day (GSOD) synoptic observations during April-May-June 1973-2013. Such extreme high temperatures are usually defined by 3 criteria: 1) Their low probability of occurrence: less than the 10% of the days. The use of absolute thresholds, associated with heat budget and physiological impacts, could be an alternative (Senevirat et al., 2012). 2) Their intensity, i.e. their amplitude in terms of standard deviations from the local climatology (Goubanova, 2007), or otherwise exceeds over absolute threshold thresholds. 3) Their severity: extreme events causing socio-economic or human losses, the notion of impact is thus of major importance for their definition (Beniston et al., 2007).

According to prior IPCC assessments (TAR, AR4 and SREX), it is very likely that increased maximum temperatures and enhanced probabilities of hot days occurrences will occur at the global scale. There is also medium confidence that warm spells/heat weave frequencies, lengths or intensities will increase in many regions (Cubasch et al., 2013). Because of its latitude, Sahel is especially concerned, with diurnal temperatures often exceeding 40°C, the global land and, to a lesser extent, the global ocean. AR4 concluded that global land-surface air temperature (LSAT) had increased over the instrumental period of record, with the warming rate approximately double that reported over the oceans since 1979. AR5 confirms previous estimates: Global LSAT increased 0.1005°C ± 0.01925°C per decade over 1901-2012 period while the rise reaches 0.262°C ± 0.05°C per decade over the 1979-2012 period, according to the observations of CRUTEN4.1. e. GHCNv3.2.0 CISS and Berkeley dataset average (Hartman et al., 2013). Changes in the length of the spells are observed and they are likely to increase but this needs to be investigated further over Sahel where severe heat can have damaging consequences for societies.

For instance, in Niamey (Niger) in April 2010 whereas Tmax reaching 47°C (Ringard et al., 2015), increased morbidity and mortality rates were observed, especially among the elderly and young children. Moreover, in some places, HWs can be associated with increased rates of atmospheric pollution.

Terminology is large: a "hot spell" implies the hottest temperature during an extreme of temperature with a small duration (a few hours), small extension (around the station) and a high frequency: a "warm spell" should be less frequent and covers a larger area; a "heat wave" (HW) exceeds thresholds of temperature most frequently and covers at least a whole region (~ 500-1000 km²). These thresholds can be absolute (T' fixed locally) or relative, exceeding 5 °C as local standards for example for Expert Team on Climate Change Detection and Indices (ETCCDI, 2013). ACMAC (Afriam Centre of Meteorological Applications for Development) classifies the extreme temperatures following five high-impact weather events; they broadcasts a mail alert when Tmax> 40°C. In ACASIS, Sahelian HW is defined (Rome et al., 2015) as a period of at least 3 consecutive days of extremely high (above the local 90th percentile) daily heat index. The Heat Index (HI) (Steadman 1979, 1994), combining temperature and relative humidity, appears as the most appropriate index, suitable for tropical climate, which takes into account the human-perceived equivalent temperature. The role of humidity is rather small in boreal spring across the Sahel, when high incoming solar radiation is combined with extremely dry soils, preventing cooling effect associated with latent heat flux. As for global scales, results show a clear warming trend over the last three decades, with a clear trend for HW events to become more frequent, last longer, cover larger areas and reach higher intensities (see also Oueslati et al. 2015). We then observe a decrease in cases of "Caution" HI and an increase in cases of "Danger" and "Extreme Danger" HI values.

# Future changes of extreme events of sea cooling in the Black Sea region in winter period of end of XXI century

## A. Savchenko (1)

(1) Marine Hydrographic Institute of NAS of Ukraine, Interaction of atmosphere-ocean, Sevastopol, Ukraine

The study of climate change at the end of the XXI century with increasing human intervention around the world is important and necessary. In particular, it is argued that unprecedented magnitude of the positive trend in surface air temperature, observed since the mid XX century, largely due to the concentration of greenhouse gases in the atmosphere associated with human activities. Moreover, this warming will continue in this century, and by the end of the century will be 2 - 5 °C. At the same time, the spatial resolution of global models, despite their continuous improvement remains insufficient to display the complex climatological and dynamical downscaling takes an additional argument in regions with underdeveloped network of meteorological stations and difficult terrain. In the current global climate models do not take into account the Crimean Mountains, the Caucasus Mountains height not exceeding 2 km, and the Black Sea is posed less than 10 points calculation area. In this study, we used input data of global model INMCM4, which is a joint in international project CMIP5. Experiment of downscaling was carried out for area Black-Caspian Sea region to further revised data, i.e. the transition from large-scale calculations of global fields to regional estimates to obtain regional climate characteristics (temperature, turbulent heat fluxes, etc.), directly with the influence of regional factors with a spatial resolution of 25 x 25 km. Thus, for the Black Sea region were calculated turbulent heat fluxes in winter 2071-2100 (scenario RCP8.5). By control period used a data set of observations for the period 1971-2000 years. In the Black Sea basin was selected region's largest winter heat fluxes from the sea surface, which is the north-western basin. This water area is interesting that in the selected area of river runoff about 80% of the total annual flow into the Black Sea. According to the scenario RCP8.5 average temperature in winter over the Black Sea basin will increase by 2 - 3 °C at the end of XXI century. The following integral characteristics of the north-western shelf of the Black Sea are in the area of the shelf bound by the 44°N and 28-34°E. For the future heat fluxes of winter periods will change as follows: sensible heat flux will decrease by 3%, and latent heat flux will increase by 22% compared to the control period. Also Bowen ratio was calculated for the average winter values that will decrease in the future to 0.34 although it was 0.43 in control period. This ratio was calculated in order to look at the share of sensible and latent heat in the total heat flux (sensible heat flux = latent heat flux = total heat flux) and look at future with high 40%. It was also interesting to see the changes in the synoptic situation during extreme cooling P = 95% of north-western part of Black Sea in the winter, where a total heat flux used to build composites. Composite fields showed that after clustering atmospheric situation in Europe have been identified 2 main types (clusters). So the first type - a anticyclone on the Baltic sea, and the second type of synoptic situation is a cyclone in the district of the Caspian Sea. So in the future period the sum of the cluster was 95% of the total heat flux in each cluster was approximately 50% to 50%. And compared to the control period, the number of events first type was little over 20% and second type almost 80% of all events P = 95%. That is, it can be concluded that the change not only the quantitative characteristics of extreme cooling, but also qualitative changes in the synoptic situation in Europe during extreme cooling of sea surface of Black Sea. The greatest danger in the future period(2071-2100) in Black Sea region are extreme events for P = 99%, while increasing total heat flux almost 40% compared to the control period and result in potential losses in fishing, oil (gas) industry, agriculture and the other in this region. Thus these results require further verification and analysis of possible risks in the future for the economy of the Black Sea region.
## Climatological analysis of trend of rainy days in Bangladesh using Mann Kendall Test

MR. Uddin (1); J. Begum (2); S. Ahmed (3)

(1) Bangladesh University of Engineering and Technology, Department of physics, Dhaka, Bangladesh; (2) Southeast University, Department of textile engineering, Dhaka, Bangladesh; (3) Comilla Victoria Govt. College, Department of physics, Comilla, Bangladesh

The impact of climate change on rainy days has received a great deal of attention by scholars worldwide. Many studies have been conducted to illustrate that changes in annual rainy days is becoming evident on a global scale. Bangladesh is likely to be one of the most vulnerable countries in the world due to climate change. This study focuses on detecting the trend of rainy days for 13 Bangladesh Meteorological Department rain gauge stations using Mann Kendall test, which was run as 5% significance level during the period 1950-2009. Seasonal and yearly trend of rainy days (greater than 01 mm/day) are studied. Variation of three threshold rainy days named: Moderated Heavy (22-44 mm/day), Heavy (45-88 mm/day) and Very Heavy (greater than 88 mm/day) are also studied. The country is divided into two regions named: wet region and dry region. All the stations showed increasing trend of rainy days except in Simrongal. The trend of Dhaka, Cox's Bazar, Simrongal and Chittagong stations are not statistically significant. All the four seasons (winter, pre-monsoon, monsoon and post-monsoon) showed statistically significant increasing trends except post-monsoon. The country's averaged threshold rainy days also showed statistically significant increasing trend except Very heavy rainy days. The yearly rainy days indicate statistically significant increasing trend. The yearly rainy days in the wet region (122 days) were higher than that of dry region (105 days). The wet (dry) region showed negative (positive) trend of rainy days during 1950-1979 whereas wet (dry) region showed positive (negative) trend of variation of rainy days during 1980-2009. The country's averaged rainy days showed negative trend during 1950-1979 and positive trend during 1980-2009. These changes indicate that the climate of Bangladesh is changing. The yearly averaged increase of rainy days was 0.35 days.

## Climate Change Signal in the 2012 Central U.S. Record (Flash) Drought

SSY. Wang (1)

(1) Utah State University, Climate Center, Logan, Utah, United States of America

The summer drought of 2012 in the central United States is instructive regarding one unique feature, that is, its rapid intensification during the early summer, evolving over a mere month from moderate to severe status. The timing of this drought's rapid intensification coincided with a subseasonal feature of widespread drying. The seasonal transition from June to July saw precipitation in the central U.S. decrease by about 25%, and this precipitation decrease is observed to have intensified since 1979. Such an intensification could enhance spring drought occurrences in the central U.S., where conditions evolved quickly from being abnormally dry to exceptionally dry, likely within a mere month from June to July. In this study, various atmospheric and land reanalysis datasets were analyzed to examine the trend calculated from 1979 to 2012 in the June-to-July seasonal transition. It was found that the change in precipitation deficit was accompanied by decreased downward radiation, evaporation flux and trophospheric subsidence, enhanced evaporative fraction, as well as an elevated planetary boundary layer height. The change in the tropospheric circulation encompassed an anomalous ridge over the western U.S. and a trough on either side; this wave-form circulation pattern is known to induce dry conditions in the central U.S. Such trends in the June-to-July seasonal shifts in precipitation, surface drying, and trophospheric circulation could have intensified and accelerated drought that took place in spring. The knowledge of the trends allows one to anticipate the evolution of spring onset of drought into the summer.

## Extreme North America Winter 2013-15: California drought and cold East Coast

SSY. Wang (1); J. H. Yoon (2); R. Gillies, (3)

(1) Utah State University, Climate Center, Logan, Utah, United States of America; (2) Pacific Northwest National Laboratory, Department of energy, Richland, WA, United States of America; (3) Utah State University, Logan, UT, United States of America

The ongoing California drought was initiated by an anomalous high-amplitude ridge system in the winter of 2013-2014. The anomalous ridge was investigated using reanalysis data and the Community Earth System Model (CESM). It was found that the ridge emerged from continual sources of Rossby wave energy in the western North Pacific starting in late summer and subsequently intensified into winter. The ridge generated a surge of wave energy downwind and deepened further the trough over the northeast U.S., forming a diple. The diple and associated circulation pattern is not linked directly with either El Niño-Southern Oscillation (ENSO) or Pacific Decadal Oscillation; instead, it is correlated with a type of ENSO precursor. Multi-model analysis using CMIP5 model outputs indicated that the connection between the diple and ENSO precursor has become stronger since the 1970s, and this is attributed to increased greenhouse gas loading as simulated by the CEM5. Therefore, there is a traceable anthropogenic warming footprint in the enormous intensity of the anomalous ridge during winter 2013-2014 and the associated drought. When projecting for the future, the large-member ensemble simulations of CEM5 indicated increases in fire counts and extreme drought occurrences, both of which are increasingly linked to the ENSO cycle.

Furthermore, the extent to which climate oscillations will modulate wildfire occurrences in the changing climate is examined. The consensus of climate model has projected a generally wetter climate for California towards the latter part of the 21st century, a scenario that seems to counter the projections of more fires in a wetter climate. Using CESM that directly output fire parameters, it is found that both the mean fire probability and annual precipitation in California are projected to increase slightly towards the end of the 21st century. However, the fluctuation in annual precipitation will amplify leading to a robust increase in the variation of vegetation and fire probability. The increased fluctuation of fire probability is associated with the amplified ENSO cycle at the 4-5 year frequency. This association suggests a potential for increasingly severe wildfires to occur more regularly in the future.

## Early and late winter cold spells over the Euro-Mediterranean region

E. Xoplaki (1); A. Toreti (2); J. Luterbacher (1)

(1) Justus-Liebig-University Giessen, Geography:

Climatology, Climate Dynamics and Climate Change, Giessen, Germany; (2) European Commission, Joint Research Centre, Ispra, Italy

Temperature extremes have a strong impact on ecosystems, societies and economies; for instance in terms of impacts on agriculture, human health, energy consumption among others. Warm summer extremes and their impacts, i.e. summer heat waves, have extensively been investigated and characterised in several studies focusing on either a recent past-current time climate projections for the next decades. Less efforts have been, instead, devoted to cold spells occurring in the Euro-Mediterranean region, although also these extreme events can have significant impacts especially in a future warmer climate. Especially for the European south, sensitivity to cold weather is greater than the northern, cooler regions, while mortality is found to increase to a greater extent with a given fall in temperature in regions with warmer winters. This study aims at characterising future changes in the occurrence, intensity, and duration of cold spells and their spatial variability over the Euro-Mediterranean region. The focus is on early and late cold season events (December and March, respectively), especially conditional on the occurrence of a presiding warmer autumn (winter for the late season events). Mid- and late 21st century potential changes are investigated by using the recently released Euro-Cordex regional climate simulations both under the mid-range mitigation emission scenario RCP4.5 and the high emission scenario RCP8.5.
# 1114 - Global emissions and their implications for climate targets

## ORAL PRESENTATIONS

### K-1114-01

#### Short Lived Promise? Short-lived climate pollutants, cumulative carbon and emission metrics

M. Allen (1)

(1) University of Oxford, School of geography and the environment, Oxford, United Kingdom

The relative priority given to reducing carbon dioxide emissions versus other forms of anthropogenic climate pollution, such as the Short Lived Climate Pollutants (SLCPs) methane and soot, could be a significant issue for many countries, in the preparations for COP21. The decision to adopt countries to adopt their own metrics to add up the role of different gases in their contributions to the overall emission reduction goal highlights the need for clarity on these issues. This talk will review the findings on cumulative carbon and emission metrics in the IPCC 5th Assessment, and present a new Policy Brief from the Oxford Martin School, with the same title, that discusses and elucidates these issues.

Any strategy to prevent dangerous anthropogenic interference in the climate system must limit cumulative emissions of the main long-lived climate pollutant, carbon dioxide (CO2). To limit the warming they cause to 2°C, for example, CO2 emissions must be limited to a cumulative budget of about one trillion tonnes of carbon, over half of which has already been released. That said, other climate drivers are likely to contribute to peak warming, and hence reduce the carbon budget consistent with 2°C of total anthropogenic warming. Current emissions of both CO2 and SLCPs also affect the rate and magnitude of climate change over the next few decades, although it is important to note that the climate benefits of reduced emissions on these short timescales could be comparable to, and hence potentially outweighed by, natural climate variability, particularly on regional scales.

Reductions in SLCP emissions could be achieved at relatively low cost and with substantial co-benefits but, I will argue, implementing these reductions immediately would have little impact on peak warming unless CO2 emissions are substantially reduced at the same time. Hence any decisions on policy priorities between CO2 and SLCPs, and any country's choice of emission metric to relate them, represents in essence a matter of intergenerational prioritisation. Advancing measures to reduce SLCP emissions could provide some climate benefit to the current generation through reduced warming over the next few decades, while immediate reductions in CO2 emissions also deliver a more substantial climate benefit to future generations.

Any emission trading system or climate policy that addresses emissions of several different greenhouse gases together in a single 'multi-gas basket' requires some form of metric to specify what a given amount of one greenhouse gas is 'worth' in terms of another. The choice of metric to compare the impact of emissions of methane and other SLCPs with the impact of CO2 depends on the timescale of interest. If the policy goal is to limit peak warming, it also depends on the ambition and success of future mitigation measures.

The standard '100-year Global Warming Potential' (GWP100) provides (despite its name) an approximate indication of the relative importance of emissions of different gases to the increase in global temperatures over the next 20 to 40 years. GWP100 is therefore a measure of impact on peak warming if and only if temperatures are expected to be approaching stabilization within 40 years, for which CO2 emissions need to approach zero on a comparable timescale.

As long as CO2 emissions continue to rise, policies that allow SLCP measures to be exchanged, traded or offset against CO2 emission reductions using GWP100 over-

value the impact of SLCP measures on peak warming and hence risk discouraging the CO2 emission reductions that are required to stabilize temperatures. Replacing GWP100 with a different metric would not solve this problem because any metric that is suitable for long-term impacts would be misleading for short-term impacts and vice versa. Using a metric that changes over time would help, but introduces greater complexity and uncertainty.

Rather than discussing a change of metric within a single 'multi-gas basket' framework, policymakers should focus instead on introducing additional instruments, safeguards or measures to ensure that cumulative emissions of CO2 are limited to an overall budget consistent with meeting the 2°C goal. A simple precaution would be to avoid trading or offsetting between CO2 and SLCP emission reductions until global CO2 emissions are falling fast enough to allow a robust and realistic assessment of the remaining time to peak warming.

### O-1114-01

#### The changing face of global fossil fuel carbon dioxide emissions

R. Andres (1); T. Boden (2)

(1) OAK RIDGE NATIONAL LABORATORY, LOS ALAMOS, NM, United States of America; (2) OAK RIDGE NATIONAL LABORATORY, OAK RIDGE, TN, United States of America

Global fossil fuel carbon dioxide emissions have been persistently increasing for the last 250 years. This increase is a primary driver of the atmospheric disequilibrium impacting and changing atmospheric, terrestrial, and oceanic systems.

The Carbon Dioxide Information Analysis Center (CDIAI) at Oak Ridge National Laboratory (ORNL), U.S.A., has been estimating fossil fuel carbon dioxide emissions for more than 20 years. These emission estimates are based on fuel statistics, carbon contents, and the fraction of fuel oxidized. This has resulted in an annual time series of emission estimates from the year 1751 to the present. Annual updates add another year to the time series as well as revising data in previous years. Over the years, this basic time series has been supplemented by mapping the emissions at one degree latitude by one degree longitude over the time series in terms of stable carbon isotopic (13C) signature, parsing the time series from annual to monthly time steps, and describing the uncertainty of the global total FFCO2 emissions. Underway now is an uncertainty evaluation of the annual and monthly mapped emissions.

This time series reveals interesting trends when disaggregated by country fuel type, and source. For example, the proportion of emissions from Kyoto Protocol Annex B and non-annex B countries has changed since Protocol signing to today. The role of coal in fueling global energy systems has changed from being the primary fuel to becoming secondary to liquid fuels to again becoming the primary fuel. The practice of flaring excess gas in oil fields, as a proportion of total energy production, has decreased by more than a factor of two since the year 1950. Release of carbon during cement production has increased by about 15% from four since 1950 and now equates to about 5% of global carbon dioxide emissions from fossil fuel production.

The global fossil fuel carbon dioxide uncertainty analysis resulted in a 2σ range of 1.0 to 13%, which can be greatly simplified to 8.4% (2σ). This uncertainty in the magnitude of global fossil fuel carbon dioxide emissions has become an important component to our overall understanding of the global carbon cycle. The uncertainty in the magnitude of mapped fossil fuel carbon dioxide emissions will become a limitation to our understanding of local carbon cycles in the absence of detailed local inventories and observations.

The emission time series has been used by the Global Carbon Project in its annual evaluation of the global carbon budget. The budget is a high level check on the
understanding of carbon flows throughout the Earth system. Uncertainty propagation through the budget constrains our knowledge about the carbon budget.

## O-1114-02

### Potential emissions of CO2 and methane from proven reserves of fossil fuels in the context of the global remaining carbon budget

R. Heede (1); N. Oreskes (2)

(1) Climate Accountability Institute, Snowmass, CO, United States of America; (2) Harvard University, and Climate Accountability Institute, Department of the history of science, Cambridge, MA, and Snowmass, CO, United States of America

Scientists have argued that no more than one-third of proven recoverable fossil fuel reserves can be extracted and consumed by 2050 if we are to avoid exceeding the 2°C temperature target agreed to in Copenhagen (IEA 2012). The remaining carbon budget is ≤275 gigatones of carbon (GtC) (assuming a 66% probability of staying below 2°C. IPCC 2014), whereas recoverable fossil fuel reserves contain an estimated 733 GtC (based on BP 2014: IPCC 2014 cites reserves of 1.0–1.9 TtC). Global reserves are based on national assessments without reference to reserve ownership or productive capacity. The studies that do identify corporate owners are limited to investor-owned companies listed on major securities exchanges. We identify the largest seventy investor-owned and state-owned companies that possess the financial and technical capacity, and the ownership or production rights) to exploit and produce the majority of the world's recoverable reserves of oil, natural gas, and coal. We quantify the potential emissions of CO2 and methane for each entity's reserves, and compare the emissions to the global remaining carbon budget.

This presentation will report on recent estimates of the potential emissions of CO2 and methane from the proven reserves declared by the world's largest producers of oil, natural gas, and coal, focusing on the seventy companies and eight government-run industries that produced 63 percent of the world's fossil fuels from 1750 to 2010 (Heede 2014). Full production of these reserves (accounting for non-energy uses and flared and vented CO2) is estimated to result in emissions of 440 GtC of carbon dioxide, or 60 percent of the remaining 275 GtC carbon budget. Of the 440 GtC attributed, the 42 investor-owned oil, gas, and coal companies hold reserves with potential emissions of 44 GtC, whereas the 28 state-owned entities possess reserves of 210 GtC – equivalent to 16 percent and 76 percent of the remaining carbon budget, respectively. Government-run industries possess reserves of 185 GtC (16% of the remaining budget).

This analysis shows that 1) the profound risk to the future arises not so much from the proven reserves in the hands of publicly-traded corporations, but from their ongoing exploration for and development of new fossil fuel resources, and 2) that while the investor-owned companies may be most vulnerable to investor and consumer pressure, effective action to control climate change must also include the state-owned companies and governments that hold the preponderance of reserves. This work will inform climate scientists, energy and emission scenario modelers, climate negotiators, national climate and energy policy leaders, and investors in fossil fuel companies with practical data on the potential consequences of fossil fuel reserves held by specific companies with the capacity, financial resources, and incentives to extract, refine, and market carbon fuels. These supra-national companies may play a critical role in delivering solutions to reduce net emissions from the fossil fuel sector.

## O-1114-03

### Net Carbon gain and loss in the world's tropical vegetation: New estimates for the 2012 – 2014 period

A. Baccini (1); W. Walker (2); L. Carvalho (3); D. Sulla-Menashé (4); RA. Houghton (2)

(1) The Woods Hole Research Center, Woods Hole, United States of America; (2) The Woods Hole Research Center, Woods Hole Research Center, United States of America;

(3) Boston University, Dept. of mathematics and statistics, Boston, United States of America; (4) Boston University, Geography, Boston, United States of America

Tropical forests store 471 Pg C, 55 % of global forest stocks, and emissions from land use and land cover change (LULCC) are the second largest anthropogenic source of carbon dioxide to the atmosphere. Despite the new convergence of climate change estimates for the tropics, a whole, more estimates for individual regions are much more variable, particularly at national and subnational scales. Forest disturbance and successive processes determine the magnitude and distribution of sources and sinks of atmospheric carbon dioxide, which influence climate. Tracking terrestrial carbon fluxes and predicting how tropical forests will respond to continuous global change relies on accurate estimates of annual changes in the density and distribution of carbon stocks at local to global scales. Thus, determining the magnitude and distribution of sources and sinks at annual time steps with measurable uncertainty is of scientific and political importance. While significant progress has been made in the quantification of single-epoch carbon storage across large areas of the globe, robust assessments of aboveground carbon dynamics remain lacking. Existing evidence for tropical forests as a carbon sink is based on a limited number of repeated in situ measurements that have been scaled to characterize sequestration dynamics across large regions of the tropics. Advancing the work of Baccini et al. (2012), we combine wall-to-wall satellite image data, Light Detection and Ranging (LiDAR) measurements and field data to empirically examine aboveground biomass dynamics (i.e., gains and losses) and quantify net changes in carbon density (i.e., rates of carbon sequestration and emissions) at annual intervals for the period 2002 to 2014 (LiDAR data are from the 2014 annual time series measurements of carbon density according to piecewise linear trends. Thirteen years (2002–2014) of pantoparal satellite data serve to provide direct, measurement-based evidence that the world's tropical forests are a net carbon source on the order of 420 Tg C yr⁻¹. This net release of carbon consists of net losses of 548 Tg C yr⁻¹ and net gains of 128 Tg C yr⁻¹. The gains result free of forest growth, afforestation and reforestation losses resulting from natural and anthropogenic processes well as both anthropogenic reductions in forest area attributed to deforestation and in biomass density within forests resulting from degradation. While the changes are widely distributed throughout the tropics, the forests of tropical America account for 75 % of the net loss. Advantages of this new approach to emissions estimation over traditional methods that rely on emission factors (e.g., carbon density) are that data are consistent and accurate (1) providing spatially explicit, consistent and accurate estimates of net emissions from forest biomass change that eliminate the need for error prone land cover classifications or area change products, (2) accounting for gains and losses without the need to explicitly define or delineate forest degradation and (3) tracking of changes in net forest carbon emissions on an annual basis with quantified uncertainty that is suitable for use in national and international policy making on REDD+ and associated mitigation actions.

## O-1114-04

### Global methane budget and natural gas leakage based on long-term □13CH4 measurements and updated isotopic source signatures

S. Schwietzke (1); O. Sherwood, (2); PP. Tans, (1); MS. Englund (2); G. Etiope, (3); A. Ionescu, (4); J.B. Miller, (1); EJ. Dlugokencky, (1); LMP. Bruhwiler, (1)

(1) National Oceanic and Atmospheric Administration, ESRL/GMD, Boulder, CO, United States of America; (2) University of Colorado at Boulder, Institute of arctic and alpine research, Boulder, CO, United States of America; (3) Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; (4) Babes-Bolyai University, Cluj-Napoca, Romania

Methane (CH4) is a greenhouse gas (GHG) with the second largest global radiative forcing contribution after CO2. Its atmospheric abundance has increased by about 150% since the industrial revolution. Given the critical role of CH4 in global climate change, it is important to better understand its sources and sinks. Improving the estimates of individual source magnitudes – such as fossil fuels, agriculture, and other anthropogenic and natural sources – helps prioritizing CH4 emissions mitigation efforts
and modeling future climate change. Policy-makers rely strongly on accounting-based national and international emissions inventories to inform mitigation regulatory action. However, recent field studies indicate that emissions inventories may significantly underestimate fossil fuel CH4 emissions (those associated with extraction and use of natural gas, oil, and coal). In this work, atmospheric measurements from the National Oceanographic and Atmospheric Administration (NOAA) Global GHG Reference Network spanning the past three decades are used to derive long-term estimates of global CH4 emissions from fossil fuels and other sources in comparison with inventories and other estimates. Atmospheric measurements include global CH4 and the stable isotope 13CH4, which are used in a global box-model to constrain source magnitudes. First, probability distribution functions of the key model parameters are derived including literature isotopic source signatures, isotopic fractionation factors, atmospheric CH4 lifetime, and fossil fuel hydrocarbon gas compositions. Our isotopic source signature distributions are based on the largest literature survey to date, which suggests significant corrections compared to previous studies. Second, a Monte Carlo simulation of the box-model is performed to quantify confidence intervals of individual emissions sources. We find that attributing the majority of increased CH4 levels over the past three decades to microbial sources is consistent with 13CH4. The sum of CH4 emissions from the fossil fuel industry and geological seepage is significantly larger than previous estimates, which is compatible with pre-industrial isotopic ice core records. Third, recently published estimates of global CH4 emissions from oil and coal production are subtracted from our global fossil fuel CH4 results to quantify global CH4 leakage from the natural gas industry during extraction, processing, transport, and distribution of the total CH4. The leakage and fraction of total production has decreased steadily over the same period indicating industry efficiency improvements. The results highlight a major gap in our understanding of global CH4 emissions. This motivates increased collaboration efforts between the physical sciences and regulatory agencies to explain and reconcile the differences between atmospheric measurements and emissions inventories.

O-1114-05

## Arctic Deposition of Black Carbon from Biomass Burning in Northern Eurasia from 2002 to 2012

WM. Hao (1); N. Evangelou (2); Y. Balkanski (3); S. Urbanski (1)

(1) US Forest Service, Missoula Fire Sciences Laboratory, Missoula, MT; (2) United States of America; (3) Norwegian Institute for Air Research, Atmospheric and Climate research, Kjeller, Norway; (4) Institut Pierre et Simon Laplace, Laboratoire des sciences du climat et de l'environnement, Gif sur Yvette Cedex, France

Black carbon (BC) in smoke particles in Northern Eurasia can be transported and deposited on Arctic ice and accelerate ice melting during certain times of the year. Thus, we examined daily BC emissions from fires in this region a melting day BC x 500 m resolution from 2002 to 2012 and modeled the BC transport and deposition in the Arctic. Black carbon emissions were estimated based on MODIS land cover maps and detected burned areas, the Forest Inventory Survey of the Russian Federation, and biomass specific BC emission factors. Annual burned areas in Northern Eurasia varied considerably with an average of 260,000 km² for the study period. Grassland dominates the total burned area (61%), followed by forest (27%). For grassland fires, about three-quarters of the area burned occurred in Central and Western Asia and about 17% in Russia. More than 90% of the forest burned area was in Russia. Annual BC emissions from Northern Eurasian fires varied enormously with an average of 0.85 Tg. In contrast to burned area, BC emissions from forest fires accounted for about two-thirds of the emissions, followed by grassland fires (15%). More than 90% of the BC emissions from grassland fires in Western Asia was the major region for BC emissions from grassland fires (53%). Overall, Russia contributed 83% of the total BC emissions from fires in Northern Eurasia.

The transport and deposition of BC on Arctic ice from all the global sources was estimated using the MLDz-OR-ICNA global chemistry-aerosol-climate model at the LCESE. Overall, about 55% of emitted BC was deposited on the

Arctic ice. Biomass burning over Northern Eurasia was the dominant source (54%) of the BC deposition in the Arctic. Anthropogenic sources in Northern Eurasia accounted for 24% of BC deposition in the Arctic, while all sources from North America and southern Asia comprised the balance. Seasonally, biomass burning contributed 68% of the BC sources in the Arctic in the spring and 81% in the summer, while anthropogenic sources contributed 73% in the winter and 67% in the fall. About 49% of total BC deposition in the Arctic originated from Asia and only 5% was from Europe. Geographically, in Asia, Siberia was the major source (59%) for the BC deposition in the Arctic, followed by Kazakhstan (18%) and Mongolia (8%).

These results are critical to understanding the contribution of black carbon from biomass burning to accelerated melting of Arctic ice under future climate conditions.

## 1114-POSTER PRESENTATIONS

P-1114-01

### Lagrangian modeling of global atmospheric methane (MAIOLICA II project)

F. Arfeuille (1); S. Henne (1); D. Brunner (1)

(1) EMPA, Dübendorf, Switzerland

In the MAIOLICA II project, the Lagrangian particle dispersion model FLEXPART is used to simulate the global atmospheric CH4 over the 1990-2010 period. In this Lagrangian framework, 3 million particles are permanently transported based on wind fields from ERA-interim. The history of individual particles can be followed allowing for comprehensive analysis of transport pathways and timescales and to establish a link between sources (emissions) and receptors (measurement stations) in a straightforward manner, a prerequisite for source inversion problems. FLEXPART was extended to incorporate the methane loss by reaction with OH. CH4 mass is further lost by daily uptake and stratoclimatic loss reactions with prescribed Cl and O(1D) radicals.

Sources are separated into 245 different tracers, depending on source origin (anthropogenic, wetlands, rice, biomass burning, termites, wild animals, oceans, volcanoes), region of emission, and time since emission (5 age classes). The inversion approach applied is a fixed-lag Kalman smoother similar to that described in Schwurhuler et al. [2005].

Results from the FLEXPART global methane simulation and from the subsequent inversion will be presented.

Bruhwiler, L. M. P., A. M. Michalak, W. Peters, D. F. Baker, and P. Tans (2005), An improved Kalman Smoother for atmospheric inversions, Atmos Chem Phys, 5, 2691-2702

P-1114-02

### Changes in the global methane budget since 2000

P. Bousquet (1); M. Saunois (1); B. Poulter (2); P. Ciais (3) ; J. P. Canadell (4); EJ. Dlugoczeky, (5); A. Peregon (1); M. Global-Carbon-Project (6)

(1) Université de Versailles St Quentin en Yvelines, Laboratoire des sciences du climat et de l'environnement, Gif sur Yvette, France; (2) Montana State University, Ecosystem dynamics lab, Bozeman, United States of America; (3) LCESE, CNRS and UVSQ, Gif-sur-Yvette, France; (4) Global Carbon Project, Ciroi marine and atmospheric research, Canberra, Australia; (5) National Oceanographic and Atmospheric Administration, Esrl/gmd, Boulder, CO, United States of America; (6) Global Carbon, Project, Paris, France

Methane is the second anthropogenic greenhouse gas after carbon dioxide. Atmospheric methane has contributed 20% of the climate forcing by long-lived greenhouse gases since pre-industrial times but also influences the oxidizing capacity of the atmosphere. With a lifetime around 10 years in the atmosphere and a diversity of emission types, methane is an important target for climate change mitigation. Observations of atmospheric methane began in 1978, reached global coverage after 1983, and now include a large variety of in-situ and remote-sensed observations. After the loss of SCIAMACHY (2002-2012), two space missions are currently producing methane
weighted-columns, GOSAT (since 2009) and METOP-ASI (since 2007).

Although sources and sinks of methane are identified, large uncertainties remain in their spatio-temporal quantification. Here, we present a synthesis of methane emissions and sinks since 2000 using an integrated approach to combine: atmospheric measurements, chemistry-transport models, ecosystem models, emission inventories, and climate-chemistry models. The results of an ensemble of atmospheric inversions (top-down) and of process-based models (bottom-up) are presented and compared. Global and regional methane budgets and their changes are presented and discussed for the period 2000-2012. Possible scenarios are presented to explain the increase of atmospheric methane after 2006, after almost a decade of stagnation. Year-to-year changes are also analysed after 2006 in order to identify robust changes as opposed to still uncertain ones.

(6) Global Carbon project / methane is a group of scientists working to improve the global methane budget : P.Bousquet, M.Saunois, B.Poulter, P.Ciais, J.Canadell, E.J.Dlugodenkency, A. Peregon, D. Bastviken, D. J. Beerling, P. Bergamaschi, D. R. Blake, G. Braisford, V. Brovin, L. Bruhwieler, S. Castaldi, D. Covey, E. Crevoisier, S. Curry, S. Denison, N. Elisei, E. Etiope, A. Finkenberg, Y. Fukuyama, N. Gedney, M. Herrero, P. Hopcroft, S. Houweling, A. Ito, R. Jackson, F. Joos, T. Kleinen, C. D. Koven, P. B. Krummel, J.-F. Lamarque, Z. Lingxi, Z. Loh, M. Marshall, T. Machida, S. Maksyutov, K. McDonald, J. Melton, G. Maenhou, I. Morino, C. Le Quéré, V. Naik, P. I. Palmer, P. Patra, S. Peng, G. Peters, I. Pison, C. Prigent, R. G. Prinn, M. Ramonet, P. Raymond, M. Rigby, K. Saad, M. S. Asia, M. Santini, R. Schröder, I.J. Simpson, R. Spahnli, P. Steele, L. Tabor, H. T. Johansen, T. Tubino, G. R. van der Werf, N. Vlovy, A. Voulgarakis, W. Wagner, M. Weitz, D. J. Wilton, D. Worthy, D. Wünch, Y. Yoshida, T. Yokota.

P-1114-03

Fossil fuels ultimate recovery appraisal,
clue to climate change modelling

B. Durand (1)

(1) retired from ENS de Géologie, Geology, Avment, France

According to ICCP report, Climate Change 2013 (the Physical Science Basis), as shown by figure SPM.10 of
Surface for Policymakers, temperature of the earth's
at the end of the century would depend primarily
on the cumulative quantity of CO2 from anthropogenic
sources emitted since 1860. Because roughly 80 % of
these emissions are produced by fossil fuels combustion,
recoverable quantities are the main drivers of climate
change during this century and the followers.

Since production histories of fossil fuels are already long, it is now possible, as shown in this paper, to predict with a good approximation their quantities to be ultimately produced. This is done by statistical methods, using mainly the construction of creaming curves of technical reserves discoveries and Hubbert's production linearization.

These quantities are such that a temperature increase till
the end of the century as high as described by RCP 8.5
and 6, is highly improbable even in a Business As Usual
scenario. And staying below a 2 °C temperature increase
from 1860 on remains obviously possible, provided
that use of coal is now strongly restricted. This is the
responsibility of the main coal consumers.

10 of them, China, the USA, India, Japan, South Africa, Russia, South Corea, Germany, Poland and Indonesia, consume nearly 90 % of the world's total coal production. As a result, these 11 countries also produce for the moment most of the world CO2 emissions. Therefore they are, according to ICCP modeling, the main drivers of climate change. They should definitely cooperate to undertake immediate and strong action.

Exploitations of bituminous shales, methane hydrates, or of coal by underground gasification are not considered here. They are for the moment highly hypothetical at a large scale. Nevertheless they should not be encouraged.

P-1114-04

Extending the relationship between global
warming and cumulative carbon emissions
to multi-millennial timescales

T. Frölicher (1)

(1) ETH Zurich, Zurich, Switzerland

Climate model simulations and theoretical arguments indicate an approximately linear relationship between cumulative carbon emissions and projected global mean temperature over the 21st century and beyond in a wide set of future carbon emissions scenarios. This Transient Climate Response to cumulative carbon Emissions (TCRE) is estimated to likely (> 66% likelihood) be in the range of 0.8-2.5°C/1000 Gt carbon. TCRE is defined for peak temperature and is nearly independent of the rate of carbon emissions. Any global temperature target therefore implies a limited carbon emissions budget. TCRE is a simple and useful policy framework and may play an important role in the post-Kyoto political negotiations for a new global agreement on future carbon emissions.

A recent modeling study (Frölicher et al. 2014) using carbon pulse experiments of a comprehensive global atmosphere-ocean general circulation model (AOGCM) finds that global mean temperature may continue to increase on multi-centennial timescales even after stopping carbon emissions. In other words, these may be a significant amount of warming expected from past carbon emissions. These results imply that the linear relationship between global warming and cumulative carbon emissions breaks down when the carbon emissions are tapering off. This is in contrast to a large body of studies suggesting that global mean surface temperature stays roughly constant for a couple of centuries at the value attained when carbon emissions are stopped. These earlier studies, however, use climate models of intermediate complexity, which simplify the complexities of many processes such as cloud feedbacks.

These results call for an extension of the TCRE concept. Here I use climate models of different complexities to show that the temperature response to cumulative carbon emissions can be characterized by three different timescales or phases and that the TCRE concept is only valid during the first phase when emissions are steadily increasing. For longer time-scales, when emissions are tapering off, two new metrics will be introduced that better characterize the time-dependent temperature response to cumulative carbon emissions, namely the Peak Climate Response to cumulative carbon Emissions (PCRE) and the Equilibrium (multi-millennial) Climate Response to cumulative carbon Emissions (ECRE). I will explain why the PCRE is generally larger than the TCRE in the fully coupled AOGCMs and why the models of intermediate complexity as a class don't simulate an increase in global mean temperature after carbon emissions stoppage. The implications of these results for allowable carbon emissions required to remain below a specific global warming target will be discussed.

Frölicher, T. L., M. Winton, J. L. Sarmiento, 2014, Continued global warming after CO2 emissions stoppage, Nature Climate Change, 4, 40-44.

P-1114-05

Hydrological and biogeochemical
constraints on terrestrial carbon cycle
projections

M. Mystakidis (1) ; N. Gruber (2) ; LE. Davin (1) ; S.

Seneviratne (1)

(1) ETH Zurich, Institute for atmospheric and climate science, Zurich, Switzerland; (2) ETH Zurich, Institute of biogeochemistry and pollutant dynamics, Zurich, Switzerland

Terrestrial ecosystems are playing a crucial role in the climate system by absorbing about one third of the total anthropogenic emissions of CO2, thus providing a valuable ecosystem service to mankind. How this ecosystem service will evolve in the coming decades is still a subject of debate. This evolution depends on the response of biogeochemical cycles and ecosystems to a changing climate with more frequent and severe extreme events in some regions as well as to increased CO2 concentrations. Earth System Models which are explicitly represent the
ecosystem behavior such as the exchange of carbon and water with the atmosphere are used to study the future evolution of the land and ocean carbon cycle sinks. However, the estimates of these carbon fluxes are clearly subject to significant uncertainties. Observationally-based constraints on these simulated fluxes should therefore facilitate reduce uncertainties in future terrestrial carbon cycle projections performed for AR5 (CMIP5).

Gross Primary Production (GPP) is the total amount of carbon that is taken up by plants during photosynthesis and it is one of the main components of the land carbon cycle and driver of the carbon uptake by land. We show that over many regions models simulating high present-day GPP and Evapotranspiration (ET) tend to simulate higher increase in future GPP. Using these emergent relationships combined with present-day estimates of ET and GPP we constrain future changes in GPP. We find that the inter-model spread in future GPP is reduced by at least 50% while the increase in future GPP in northern latitudes is higher than previously thought. Our results for future changes in Water Use Efficiency (WUE), a highly significant determinant of primary production of terrestrial ecosystems, show similar behavior. Applying the observational constraints on the future land sink (NBP) reveals higher than previously thought decrease in the land sink. The inter-model spread in the land sink is reduced by more than 30% and in most of the constrained ensembles the terrestrial biosphere is even turned into a net carbon source by the end of the century. Our findings therefore have several implications on the future productivity of ecosystems and the atmospheric CO2 concentrations

P-1114-06

Air Pollution Emissions and Potential for
Co-Benefits in Megacities of South Asia

BR. Gurjar (1)

(1) Indian Institute of Technology Roorkee, Civil Engineering Department, Roorkee, India

The South Asian region is highly and densely populated and includes 5 megacities (each with population more than 10 million) and hundreds of large and medium size cities. Megacities in South Asia are namely - Delhi, Mumbai and Kolkata (India), Dhaka (Bangladesh) and Karachi (Pakistan). Constantly increasing energy-intensive urban activities in burgeoning cities areas are responsible for a large share in the unacceptably high emissions of those air pollutants, which are responsible for poor air quality, adverse health effects and also climate change. High levels of Air Pollution in South Asia came into highlight by the South Asian haze called Atmospheric Brown Cloud (ABC). The annual premature deaths due to ABC were estimated equal to 100,000s in the South Asian region. Whereas, recent estimates of the burden in India show approximately 1.04 million premature deaths and 31.4 million disability-adjusted life years (DALYs) to be attributable to household air pollution (HAP) resulting from solid cooking fuels. Numerous policy measures and technological interventions are being tried in India and other countries to curb the air pollution. However, there is a growing interest in adopting those measures which can reduce air pollution emissions resulting in not only air quality improvement and health benefits but also in climate change related co-benefits.

This presentation would provide an analysis of the urban pollution emissions and potential for health and climate change related co-benefits in South Asian megacities. Most of the South Asian countries are in the stage of developing or emerging economies, and India is the fastest growing economy among them. Given the increasing trend of energy use and emissions in South Asian cities, present study is a step to make governments and people aware of the extent and intensity of ambient as well as indoor air pollution problem. The analysis presented in this study is expected to help initiate appropriate policy measures and suitable action plans to limit air pollution emissions and adopt ways based on co-benefits approach that can promote the sustainable development - especially in South Asia.

P-1114-07

Cumulative carbon emissions modulated
by policy options for limiting warming to
below 1.5 and 2°C

J. Rogelj (1); M. Schaeffer, (2); M. Meinshausen, (3)

(1) IIAAS, Laxenburg, Austria; (2) Climate Analytics, Berlin, Germany; (3) University of Melbourne, Australian-german college of climate & energy transitions, school of earth sciences, Melbourne, Australia

Cumulative emissions of carbon dioxide, or so-called carbon budgets, have recently received increasing attention in the climate policy arena. Not only are they part of the headline statements of the most recent assessment of the Intergovernmental Panel on Climate Change (IPCC), they have also been proposed as guidance for long-term emission reduction goals within the international climate negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). For example, directly following from the concept of a carbon budget is that as soon as 2055 to 2070, global net emissions of CO2 will have to be phased-out to zero in order to stay below 2°C warming with a likely chance.

A thorough understanding of the interplay between policy choices and the amount of carbon emissions compatible with specific temperature limits gains therefore in importance, in particular because the amount of future carbon emissions compatible with limiting warming to below the 1.5 or 2°C thresholds is vanishing quickly with time. Mitigation costs are related to the size of the carbon budget and can significantly affect with a delay of strong decarbonisation, as weaker reduction ambition early on comes with the necessity of much stronger reduction rates later.

We provide key insights that link the theoretical concept of carbon budgets to a real-world context, by quantifying policy-relevant emission-scenario aspects that increase or decrease cumulative carbon emissions compatible with limiting temperature limits. In particular, we focus on specific temperature limits, like 1.5 or 2°C relative to preindustrial. To achieve this, we explore dimensions not previously assessed by the IPCC.

First, we show that the choice of methodology to derive compatible carbon emissions from integrated multi-gas emission scenarios plays a non-negligible role. Both the influence of non-CO2 forcing variations and the timescales of the Earth system response lead to lower compatible carbon emissions when derived from low instead of high emission scenarios. Second, as non-CO2 forcing has the potential to modulate carbon budgets, we assess the potential influence of the mitigation of so-called short-lived climate pollutants (SLCP, like methane, soot, or hydrofluorocarbons) on the size of compatible carbon emissions. We show how, due to technological linkages between the sources of CO2 and some SLCPs, the potential impacts can vary strongly across species. Third, we explore how socio-economic developments and technological policy choices can influence the size and cost of a carbon budget for meeting a specific temperature goal by, often inadvertently, influencing the proportion of CO2 to non-CO2 forcing. Finally, by using multi-gas characteristics of a large set of emission scenario as well as theoretical phase-out pathways we explore the implications for the timing of global net zero carbon emissions.

P-1114-08

Specification of anthropogenic VOC emissions
from observations in contrasted
urban environments: a basis for emission
inventory evaluation and the definition
of CMIP (Coupled Model Intercomparison
Project) historical emission inventory

T. Salameh (1) ; A. Borbon, (1) ; C. Afif, (2) ; S. Sauvage, (3) ; N. Locolce, (3) ; C. Granier (4)

(1) Laboratoire d'analyse des systèmes atmosphériques (LISA), IPSL, CNRS,UMR7583, UPEC and UPD, Crétel, France; (2) Unité Environnement, Génomie Fonctionnelle et Etudes Mathématiques, Saint Joseph University, Beirut, Lebanon; (3) Mines Douai, Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), Douai, France; (4) CNRS, LATMOS/IPSL, Paris, France

Having accurate trace species emission estimates is critical in the development of basic scientific knowledge and to assess atmospheric chemistry, air quality, and climatic conditions at present and in the future. In addition, detailed emissions data are also required at high resolution for the design of feasible controls aimed at reducing emissions of pollutants, and for the evaluation of the efficiency of
the implemented policies. Therefore, concerted efforts in emission inventory development are necessary to improve the quality of the emission estimates and to be able to reproduce air quality conditions in models. In this context, the CMIP project was established to provide a basic support for the IPCC future report (AR6). The CMIP Panel has requested further improvements on the emissions data by using observations, as well as on the emissions spatial and temporal resolution. Among others, a high priority is given to the development of anthropogenic hydrocarbon and particle speciation.

Non-Methane Volatile Organic Compounds (NMVOCs), emitted from various sources, are of particular interest since they affect urban air quality and regional climate change by contributing to the formation of tropospheric ozone, PAN and Secondary Organic Aerosols. According to Shindell et al. (2012), NMVOC reductions could help slow the near-term rate of climate change because of their influence on short-lived climate forcers (e.g., ozone, methane, aerosols). Thus, reducing NMVOC emissions provides regional to global benefits to air quality and climate (Fry et al. 2014). Some studies have shown that the NMVOC composition depends on the regional characteristics, even among the northern mid-latitude megacities (Borson et al., 2013). These discrepancies may be important if we consider the UNFCC Non-Annex 1 countries.

Here, we propose to make an assessment of the spatial and temporal variability of the composition of NMVOC anthropogenic emissions from recent and decadal observations in urban areas in order to define more accurate and representative NMVOC emission sources profiles. The main objectives are: (1) the establishment of NMVOC emission sources profiles from in-situ observations or by near field measurements, (2) the analysis of seasonal and interannual variability of NMVOC emissions composition, and (3) the evaluation of the anthropogenic emission inventories.

This work is based on the most recent results of several long-term (air quality, nitrogen networks) and intensive measurement campaigns (MEGAPOLI - Paris, 2009, CalNex.) in post-industrialized regions (northern mid-latitude cities) and in the Eastern Mediterranean Basin within the TRANSEMED initiative. According to the ACCMIP and RCPs inventories, the total anthropogenic emissions of NMVOCs in the MEA region were constantly increasing reaching ~15 Tg in 2010 whereas in USA and Europe, the NMVOCs emissions were decreasing reaching ~10 Tg in 2010 (ECCAD database). A very detailed and unique multipollutant database was generated in a city of the Middle East, Beirut, with a focus on the organic carbon, and in Istanbul. Since, the current NMVOC speciation applied in models needs updating, source profiles were determined with field measurements close to the main potential emitters (Salameh et al. 2014).

### References:

Borson et al., 2014. Emission ratios of anthropogenic VOC in northern mid-latitude megacities: observations vs. emission inventories in Los Angeles and Paris. J. Geophys. Res., vol. 118, 2041-2057.

ECCAD database: http://ecad.sedoo.fr/ecad_extract_interface/JSF/page_products_ensjf

Fry et al., 2014. Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions. Atmos. Chem. Phys., 14, 523-535.
Salameh et al., 2014. Speciation of Non-Methane Hydrocarbons (NMHC) from anthropogenic sources in Beirut, Lebanon. Environ Sci Pollut Res, 21, 10867-10877.
Shindell et al. 2012. Simultaneously mitigating near-term climate change and improving human health and food security. Science, 335, 183-189.

## P-1114-09

### Black Carbon emission and its climate implication in Pakistan

#### I. Shahid (1)

(1) Institute of Space Technology, Islamabad, 1-Islamabad highway near Rawat Toll plaza Islamabad, Islamabad, Pakistan

Black carbon (BC) is a product of incomplete combustion (burning that gives off smoke). It is the solid, mostly pure carbon component of soot that is capable of absorbing light at all wavelengths. Black carbon emissions in South Asia are primarily derived from four sectors: residential,

industrial, transportation, and biomass burning (field burning, cook stove burning). The residential sector contains the largest single source of black carbon emissions in South Asia. The transportation and industrial sectors are also significant contributors (US EPA 2012). Black carbon deposited on snow and ice darkens the surface and decreases reflectivity, thereby increasing absorption and accelerating melting. Kopac et al., (2011) reported the role of BC in Himalaya glacier melting and change of radiative forcing in the region due to BC.

Emission inventories and analyses of aerosol samples indicate that more than half of the black carbon emitted in South Asia comes from the burning of biofuels, especially in traditional cook stoves. Shahid et al., (2015) reported that burning of different wood species for cooking emits 22% BC of the total amount of biomass burned. More sources include burning of coal (for example in brick kilns), exhaust from diesel vehicles and generators, waste burning, and forest fires. Many sources of black carbon also co-emit other substances that are less light-absorbing, or that scatter light, including brown carbon, organic carbon, and sulfate. Emissions from diesel trucks have a higher percentage of pure black carbon than emissions from open fires. The overall effect of BC in any region will therefore be a result of local / regional / global emission, climate and geography. For example in the Himalayas BC can amplify the effects of enhanced global warming while, in addition, causing surface dimming which can reduce crop productivity. There have been efforts to build emission inventories in Pakistan, however, this has been sporadic and specific. Three local efforts, one in 1990, another in 1994 and the latest in 2009 have all focused on greenhouse gases (GHG), and BC carbon is ignored. In global and regional emission studies, BC emissions are outpaced. In this study BC emissions have been estimated from different sectors using Atmospheric Brown Cloud emission inventory manual with emphasis of biomass burning for cooking and field burning (crop Residue). Unfortunately no sector specific emission factors are available. Thus we used emission factors that have been already published and closely related to Pakistan environment. During the year 2013-14, 16.923 x 106 Hectare area was cultivated for crop production, and 116 x 106 tonnes of crops were produced which incurred produced 40 x 106 tonnes of dry mass that was burnt in field. Thus single source of crop residue burning emits about 24 mega tonnes of BC along with other pollutants. Based of this data emission maps will be generated for gridded emissions over Pakistan.

These are the preliminary results, work is going on and hopefully will be able to finish till June.

## P-1114-10

### National and regional contributions to global climate change

RB. Skeie (1) ; JS. Fuglestedt (1) ; M. Allen (1) ; T. Berntsen (1); GP. Peters (1)

(1) CICERO, Oslo, Norway

According to the "Brazilian Proposal" from 1997 the industrialized countries should reduce emissions proportional to their contribution to temperature increase. The emissions of Greenhouse Gases (GHG) and Short-Lived Climate Forcers (SLCFs) have changed dramatically over the last decade with large regional differences, suggesting that previous estimates are outdated. In this work we update earlier estimates of the contributions to a global mean temperature change from countries and regions, and perform deeper analysis of various scientific and policy related choices. Which time period should be accounted for when calculating the countries' contributions? We show the importance of the start year, end year, and evaluation year on countries' contributions. Another choice is which forcing components that should be included in the analysis. First we consider the contribution of CO2 from fossil fuels and then we explore how the results are affected when all Kyoto gases and CO2 from land use change are included, and then non-Kyoto gases together with SLCFs. Time series of emissions of GHGs, aerosols and its precursors for countries/regions are constructed and a simple climate model is used to calculate the temperature response. Another policy choice is for which stage in the emission chain the contributions should be calculated (extraction, production (territorial), consumption). Finally, we will discuss the historical responsibilities of countries/regions can be seen in relation to attribution to extreme events based on work in the EU-project EUCLEIA.
## Biogenic CH4 and N2O emissions over-renewable land CO2 sink: implications for climate change mitigation

H. Canadell (4); C. Lu, (1); P. Ciais (2); A. Michalak, (3); J. P. Canadell (4); E. Saikawa, (5); D. Huntzinger, (6); K. Gurney (7); S. Sitch, (8); B. Zhang, (1); J. Yang, (1); P. Bousquet (9); LMP. Bruhler, (10); G. Chen, (11); EJ. Dlugokensky, (10); P. Friedlingstein (8); J. Melillo, (12); S. Pan, (1); B. Poulter (13); R. Prinn, (14)

University, School of Forestry and Wildlife Sciences, Auburn, AL, United States of America; (2) LCEA, CNRS and UVSQ, Gif-sur-Yvette, France; (3) Carnegie Institution for Science, Department of global ecology, Stanford, United States of America; (4) Global Carbon Project, Ciroso marine and atmospheric research, Canberra, Australia; (5) Emory University, Department of environmental studies, Atlanta, United States of America; (6) Northern Arizona University, School of earth sciences and environmental sustainability, Flagstaff, United States of America; (7) Arizona University, School of Forestry and Wildlife Sciences, Tucson, United States of America; (8) University of Exeter, Exeter, United Kingdom; (9) Université de Versailles St Quentin et Yvelines, Laboratoire des sciences du climat et de l'environnement, Gif sur Yvette, France; (10) National Oceanographic and Atmospheric Administration, Eslr/gmd, Boulder, CO, United States of America; (11) Oak Ridge National Laboratory, Environmental Sciences division, Oak Ridge, United States of America; (12) Marine Biological Laboratory, The ecosystem center, Woods Hole, United States of America; (13) Montana State University, Ecosystem dynamics lab, Bozeman, United States of America; (14) Massachusetts Institute of Technology, Center for global change science, Cambridge, United States of America

The stabilization of greenhouse gas (GHG) concentrations in the atmosphere requires reducing net anthropogenic GHG emissions and increasing the capacity of carbon sinks in the biosphere. Although global terrestrial CO2 uptake partially mitigates global warming, its contribution may be offset or even overturned by the increasing biogenic emissions of methane (CH4) and nitrous oxide (N2O). Of particular importance to climate change mitigation policies is the ability to evaluate the net balance of these three GHGs in the terrestrial biosphere. Here we synthesized multiple estimates of CO2, CH4 and N2O from various studies to investigate the net biogenic GHG budget (NBBG) and the global carbon sink. Based on 22 bottom-up studies using terrestrial biosphere models, empirical and inventory-based approaches and 7 top-down studies using atmospheric inverse models, we conclude that global terrestrial ecosystems had a net positive NBBG, indicating net greenhouse gas release to the atmosphere. After subtracting pre-industrial GHG emissions from land ecosystems, we found the global land uptake of biogenic GHG was 7.7–9.2 Pg CO2 eq/yr) was offset by 12.9% to 147% due to anthropogenically-caused emissions of CH4 and N2O. Among them, agricultural CH4 and N2O emissions (7.0 to 8.0 Pg CO2 eq/yr) play the most important role, offsetting 85% – 103% of the global land sink of anthropogenic CO2. It is clear that biogenic CH4 and N2O emissions had overwhelmed the global land CO2 sink, contributing to a net climate warming effect of all the GHG exchanged to or from the land biosphere. Our results indicate that an effective agricultural management strategies are very much needed to alleviate biogenic GHG emissions, while sustaining food and bioenergy production.

## Emissions metrics and evaluating methane-emitting natural gas as a bridge fuel

J. Trancik (1); M. Edwards (1); M. Klemun (2); M. Roy, (3)
(1) MIT, Cambridge, MA, United States of America; (2)
Massachusetts Institute of Technology, Engineering Systems Division, Cambridge, United States of America; (3) MIT, Cambridge, United States of America

Climate change mitigation is a multi-gas problem. Mitigation policies that focus on CO2 reductions alone may result in increased emissions of other gases such as CH4, leading to overshoots of climate policy goals. For example, policies aimed at reducing CO2 emissions may encourage a transition from coal to natural gas electricity, enabled by increased production of unconventional gas, but could also lead to higher CH4 emissions due to leakage in the natural gas supply chain. Therefore, it is

important to consider multiple gases in making emissions reduction commitments and in evaluating technology options to meet these goals. Here we present an approach to evaluating policies and technologies based on their multi-gas emissions.

Evaluating technology options on a common scale, or setting a national target for overall GHG emissions reductions, requires comparing different gases on a common scale. This comparison is challenging because of the dissimilar removal dynamics of different GHGs. Emissions equivalency metrics are a commonly used approach, and the global warming potential (GWP) is the most prevalent metric. The GWP converts masses of non-CO2 GHG emissions to a CO2-equivalent value based on a time-integrated radiative forcing comparison over a fixed horizon of 100 years, leading to a conversion factor that is time dependent. This static approach can lead to significant overshoots of climate policy goals, such as radiative forcing stabilization targets, because it doesn't take into account how close in time emissions occur relative to an intended stabilization year.

Here we present an alternative set of dynamic emissions equivalency metrics that evaluate emissions impacts relative to an intended radiative forcing stabilization level [1]. Our approach results in a lower impact value on shorter-lived greenhouse gases, like CH4, early on, but increases this value as emissions approach an intended stabilization time. The metrics are relatively independent of the future emissions and energy consumption scenario to be followed, and therefore can be used to evaluate policies and technologies despite the inherent uncertainty about the future. Applying the metrics to set emissions reduction targets and evaluate technologies results in substantially lower overshoots of climate policy targets than the GWP. Furthermore the metrics points to methane mitigation timelines that can allow for greater energy consumption while meeting climate policy goals [2].

How might dynamic metrics be used in setting policy targets? We will discuss a specific example by examining the US Environmental Protection Agency's Clean Power Plan target of 30% reduction in power sector CO2 emissions by the year 2030 (from 2005 levels). This policy incentivizes a shift to natural-gas based electricity generation, and could result in significant increases in power sector CH4 emissions. Applying the time-sensitive metrics mentioned above, overall GHG reductions (counting both CO2 and CH4) may only reach 10–20% by 2030, instead of the targeted 30%, without additional methane regulation. However, as shown in applying the proposed dynamic metrics, reduction rates are 3% per year would lead to the 30% by 2030 GHG reduction target to be met [3]. As demonstrated by this US example, capturing the full climate benefit of coal-to-gas technology transitions requires substantial CH4 mitigation to complement CO2-focused climate policy frameworks. The alignment of CO2 abatement and CH4 leakage reduction goals is an important problem that needs to be addressed as nations globally prepare policy proposals for the 2015 United Nations Climate Change Conference in Paris (COP21). The method proposed here provides an approach to setting coupled CO2 and CH4 reduction targets, and evaluating mitigation technologies.

[1] M.R. Edwards and J.E. Trancik, Climate Impacts of Energy Technologies Depend on Emissions Timing, Nature Climate Change, Vol. 4, pp. 347–352, 2014.

[2] Roy, Edwards and Trancik 2014. Timelines for mitigating methane emissions from energy technologies, in review. http://arxiv.org/abs/1501.03041

[3] Klemun and Trancik, 2015, Hidden effects of carbon-focused energy policies necessitate accelerated methane mitigation, in preparation.

## A global estimate of carbon stored in the world's mountain grasslands and shrublands, and the implications for climate policy

A. Ward (1); P. Dargusch (2); S. Thomas (2); Y. Liu (2); E. Fulton (3)

(1) University of Queensland, Brisbane, Australia; (2)

(3) University of Queensland, Brisbane, Queensland, Australia;

(4) Commonwealth Scientific and Industrial Research Organisation, Hobart, Australia
Carbon market and climate finance schemes (e.g., the CDM, REDD+ and the Green Climate Fund) are being investigated for their ability to achieve enhanced sustainability outcomes in terrestrial forests, lowland grasslands and marine ecosystems, all which store large amounts of carbon (C). To date however climate policy discourse has largely overlooked the conservation of existing C stored in mountain grasslands and shrublands. These ecosystems provide critical ecological goods and services to humanity yet are increasingly at risk from anthropogenic stressors including agricultural intensification, mining and climate change. The absence of a global estimate for these C stocks is likely to be one reason for their exclusion from climate change policy discussions, both on a political and scientific basis. This represents a missed opportunity in two respects: firstly, by conserving and restoring existing C stocks the impacts of climate change can be lessened; and secondly, carbon finance and climate finance might provide financial support to address the aforementioned stressors. Here we use spatial analysis and estimate there to be between 60.5 Pg C and 82.8 Pg of C contained within biomass and soils of the world's mountain grasslands and shrublands. To put this in perspective, globally tropical Savannas and grasslands, temperate forests and tropical peatlands are estimated to contain 326-330 Pg C; 159-292 PgC and 88.6 Pg C respectively. Our review of existing empirical studies and of United Nations Framework Convention on Climate Change (UNFCCC) national greenhouse accounts suggests that this C is not reliably accounted for in international carbon budgets. Our estimate is the first to provide a global point of reference, useful in developing future research and in climate policy discussions. We conclude by briefly discussing how climate finance might be leveraged to support the sustainable management of these C stocks, and in so doing uphold the other important socio-economic benefits provided to humanity.

P-1114-14

Global and China's admissible emissions pathways under various warming targets

Y. Zhu (1); Z. Wang (1)

(1) Institute of Policy and Management, Chinese Academy of Sciences, Beijing, China

Using the adaptive control model with climate system, this paper projected and compared the global admissible emission pathways under various warming targets, namely, warming 2°C above pre-industrial level, and the average level of 1850-1900, 1861-1880, 1961-1990,

1980-1999 and 1986-2005 that mentioned in IPCC-AR5 WGI report. Our study shows that the admissible emission is required to reduce by 20%, 35%, 50% and 62% until 2020, 2030, 2050 and 2100 respectively so as to limit the global warming within 2°C above the preindustrial level. This indicates that the Copenhagen agreement is hard to achieve without some breakthrough in low-carbon energy technology since the global emission is ever-increasing. Corresponding to the RCP 4.5 and RCP 6.0 in IPCC AR5 report, the admissible emissions pathways for the 2°C targets above the average level of 1850-1990 and 1861-1880 indicates that it can still rise until 2040-2045 following the historical trend and then reduce. Therefore, they are not effective targets to abate the emissions promptly. Moreover, taking 1961-1990, 1980-1999 and 1986-2005 as the base year means the admissible emission is far more than what is needed.

In view of the difficulty to achieve these targets, we further proposed three viable warming limit schemes after appraising the feasibility of the aforementioned targets, which are (1) warming 2.5°C relative to pre-industrial level, (2) warming 1°C relative to 1986-2005 and (3) 1.5°C relative to 1850-1900. The first one is a mild reduction target, which requires the global emission to stop increasing immediately and starts to reduce since 2020 gradually, finally reach a level slightly less than that in 2005 by 2100. This target is in accordance with the current abatement commitments of major countries/regions. The second one is a moderate target, which indicates the global emission should decrease at once with a smooth dropping rate. It matches the average warming expectation of RCP 2.6 scenario in IPCC report and should be a reference for each country to make further commitment. The last one is a strong target, which requires the global emission to reduce immediately with the rate similar to its growth rate during 2000-2012, indicating greater efforts need to make.

Finally, the emission rights are analyzed with different principle of allocation. The sovereignty principle is to the benefit of developed countries such as United States, European Union and Japan; some populous countries like China and India are in favor of the egalitarianism principle; the developing countries will get more emission under the principle of ability-to-pay. China will acquire about one fifth of global emissions under all the three principles, indicating the current emission level in China is compatible with its population and economy. But with all these principles, the admissible emission for China will shrink gradually under the three aforementioned warming targets and the emission gap between emission demand and supply will enlarge accordingly.

1115 - GHG Monitoring

ORAL PRESENTATIONS

K-1115-01

The GOSAT contribution to understanding global concentration distribution and regional fluxes of carbon dioxide and methane over its five-year operation period

T. Yokota, (1); S. Maksyutov (1); N. Kikuchi (1); Y. Yoshida (1); A. Bril (1); M. Inoue, (1); I. Morino, (1); O. Uchino, (1); H. Takagi (1); HS. Kim (1); R. Janardanan, (1); DA. Belikov, (2); M. Ishizawa (1); M. Saito (1); F. Kawazoe (1); M. Ajiro (1)
(1) National Institute for Environmental Studies, Tsukuba, Japan; (2) National Institute for Polar Research, Tokyo, Japan

The Greenhouse gases Observing SATellite (GOSAT) has been operating for more than five-and-a-half years since January 2009, and has completed the NIES GOSAT Project provided researchers and the general public with the retrieved column-averaged concentrations of carbon dioxide (XCO2) and methane (CH4) (SWIR Level 2 data products), which helped ascertain the global distributions of the two global warming gases and their variability with time and space. Further, with those concentration data that filled gaps in the existing surface monitoring networks, the monthly estimates of regional sources and sinks of CO2 and CH4 (Level 4 data products) were produced with

smaller uncertainties. Although there are some issues still left that need to be handled, such as region- and time-dependent biases and low retrieval success rates over the tropics, the GOSAT Project has contributed significantly to advancing the global carbon cycle studies through providing useful space-based GHG data. The Orbiting Carbon Observatory 2 (OCO-2) was launched successfully in July 2014, and now and finally, there are two CO2 monitoring platforms in space, as originally planned ten years ago. GOSAT is expected to operate and continue its observation for the next several years, even after its five-year nominal operation period ended in early 2014. Evaluating and inter-comparing data from the two platforms will yield valuable findings that can further advance the space-based GHG monitoring techniques. We will present the overview of the latest GOSAT data products and some of important research outcomes brought by the GOSAT Research Announcement researchers, and show our views on the future of space-based carbon cycle study by worldwide research collaboration.

O-1115-01

The Integrated Carbon Observation System (ICOS RI) - a European Research Infrastructure on greenhouse gases and the global carbon cycle

WL. Kutsch (1); A. Vermeulen, (2); T. Johannessen, (3); I. Levin, (4); D. Papale, (5); L. Rivier, (6); A. Watson, (7)
(1) 10 Integrated Carbon Observation System (ICOS RI), Head Office, Helsinki, Finland; (2) Integrated Carbon Observation System, Carbon Portal, Lund, Sweden; (3) University of Bergen, Bergen, Norway; (4) Università Heidelberg, Institut fuer umweltphysik, Heidelberg, Germany; (5) University of Tuscia, Viterbo, Italy; (6) LSCE, Gif sur Yvette, France; (7) University of East Anglia, Exeter, United Kingdom

Greenhouse gases contribute to radiative forcing and therefore their concentrations in the atmosphere influence climate of the Earth. The mission of ICOS RI is enabling research for understanding present state and predicting future behavior of the global carbon cycle and greenhouse gas emissions. ICOS RI does this by providing long-term observations through a distributed infrastructure with station networks designed to monitor GHG concentrations in the lower atmosphere and ocean as well as GHG exchange between terrestrial ecosystems or oceans and the atmosphere. By knowing the dynamics of GHG in the atmosphere and their fluxes, ICOS RI will provide independent data to improve and verify GHG emission inventories for international conventions.

This fusion of streams of (big) data from observational infrastructures with advanced earth system models is the next step in developing integrated knowledge on global carbon and greenhouse gas budgets. By using the complex model–data fusion systems currently under development, these observations will enable us to verify greenhouse gas fluxes on regional and national levels at unprecedented resolution in time and space.

### O-1115-02

#### Potential of in-service aircraft based greenhouse gas observations within IAGOS for constraining regional carbon budgets

S. Verma (1) ; J. Marshall (1) ; C. Roedenbeck (1) ; C. Gerbig (1)

(1) Max Planck Institute for Biogeochemistry, Biogeochemical Systems, Jena, Germany

Spatial and temporal variations of atmospheric greenhouse gas concentrations contain information about their sources and sinks as well as the exchange processes between the atmosphere and the surface of the Earth. However, the potential use of these observations in inverse models for accurate estimation of surface fluxes is hindered by the fact that they are both insufficient and unevenly distributed. The use of passenger aircraft for obtaining information about atmospheric composition and physical and chemical processes is a relatively new concept. Within the recently established European Research Infrastructure IAGOS (in-service Aircraft for a Global Observing System), highly accurate and precise in-situ observation of greenhouse gases is foreseen in the near future. Detailed and continuous measurements are made during long distance flights by hi-tech instruments deployed on board, thus providing a view of the horizontal and vertical distribution of the measured trace gases on global scale and over long periods of time. The project IGAS (IAGOS for GMES Atmospheric Service) serves as a vital link between the data collected on board civil aircraft through IAGOS and the Copernicus atmosphere monitoring service (previously known as GMES) that utilizes these measurements for applications in the field of modeling, weather forecasting and air quality forecasting.

This study is focussed on assessing the impact of measurements from IAGOS on the constraint on the regional carbon budget and quantifying the reduction in the inverse. Source–link estimates of CO2 and CH4, brought about by the use of this newly developed data stream. Anticipating the deployment of five GHG observing systems within IAGOS, the flight tracks from five in-service aircraft within MOZAIC (Measurement of Ozone and water vapour by Airbus in-service Aircraft), a predecessor project of IAGOS, are used in an inversion system to assess the constraint on the carbon budget and quantify the potential for reduction in posterior flux uncertainties. These measurement locations and times are used to evaluate the impact of data from aircraft on the reduction of flux uncertainties compared to that based on the existing global observation network, and furthermore to identify areas where the addition of these measurements would be of greatest impact. We use the Jena Inversion System that employs the Global Atmospheric Tracer Model TM3 for atmospheric transport, focussing on the period 1996–2004. The vertical aircraft profiles are input into

the inversion as two partial-column averages instead of point measurements, the lower partial column completely containing (and exceeding) the boundary layer. This is a novel approach, the advantage being that the error due to imperfect model representation of the boundary layer height and hence the vertical tracer transport near the surface can be diminished, which results in the reduction of the overall model-data mismatch error. The experimental design is such that in each simulation the existing measurement Artus Gas is augmented by pseudo-observations from up to five simulated IAGOS aircraft. Uncertainty reduction from each of these simulations is compared to the uncertainty reduction from simulations employing only the existing observation network. We find that for both CO2 and CH4, the additional constraint on the carbon budget brought about by the use of IAGOS measurements is highest for the tropical regions, the magnitude of the change in uncertainty reduction being about 20 percent.

### O-1115-03

#### Cost-effective guidelines for measurement of agricultural greenhouse gas emissions and removals

M. Richards (1) ; T. Rosenstock (2) ; K. Butterbach-Bahl, (3) ; M. Rufino (4) ; E. Wollenberg, (5)

(1) CGIAR Research Program on Climate Change, Agriculture and Food Security, Low Emissions Agriculture, Burlington, VT, United States of America; (2) World Agroforestry Centre (ICRAF), Nairobi, Kenya; (3) International Livestock Research Institute (ILRI), Nairobi, Kenya; (4) CIFOR / CCAFS, Nairobi, Kenya; (5) Gund Institute for Ecological Economics, School of environment and natural resources, Vermont, United States of America

As COP21 approaches, many non-Annex 1 countries are for the first time developing mitigation targets in the form of Intended Nationally Determined Contributions. Mitigation activities in the agriculture, forestry, and land use (AFOLU) sector are likely to be in developing countries because they provide up to 70% of the technical potential for AFOLU-based mitigation. However, decision-makers in these countries are currently limited by the lack of scientific information on emissions and mitigation potentials from the agricultural systems common in tropical developing countries.

For example, direct measurements of methane from livestock—perhaps the most significant agricultural GHG source in sub-Saharan Africa—are lacking. Measurements of soil carbon sinks from land rehabilitation and carbon storage in aboveground woody biomass are also notable gaps. The emission factors and models used in the absence of such data (IPCC Tier 1) rely on measurements largely from temperate, developed countries and their precision and accuracy in tropical developing countries is unknown.

Here we describe the SAMPLES measurement guidelines and data platform, two web-based resources for improving the availability of agricultural GHG information from tropical developing countries. Developed by scientists within the CGIAR Research Program on Climate Change, Agriculture, and Food Security (CCAFS), the guidelines provide a critical assessment of various methods that can be used to quantify GHG emissions within a developing country context. As the cost of measurement is often a constraint, the guidelines compare the available methods for each GHG driver (e.g., land use change) and source (e.g., soil emission or biomass accumulation) in terms of cost and accuracy. They recommend methods that propagate uncertainty, and provide a common to developing country farming systems such as heterogeneity of farming systems and seasonality of feed supply and quality (e.g. for enteric methane emissions). The guidelines also emphasize informed sampling design in order to aggregate GHG measurements to larger scales without unnecessary replication of measurement.

The SAMPLES data platform is the first international, publicly accessible compilation of GHG flux and carbon stock change data from tropical developing countries. While it is currently houses data from CCAFS experiments in several countries, the data platform is open to contributions from agricultural emissions studies worldwide. The platform provides a resource for compilers of national inventories, designers of monitoring and verification systems and researchers to share and access data for developing Tier 2 emission factors and calibrating models.
These two new resources provide decision-makers and the global scientific community with a means of developing and sharing the information necessary to assess, monitor and verify the GHG impacts of agricultural policies and technologies.

### O-1115-04

#### Reconstruction of super resolution oceanic pCO2 from remotely sensed data and multi-tiresures analysis: an application in the South Eastern Atlantic

V. Garcon (1) ; I. Hernandez-Carrasco (1) ; J. Sudre (1) ; H. Vahia (2) ; C. Garbe (3) ; A. Paulmier (4) ; B. Dewitte (4) ; S. Illig (4)

(1) CNRS, Toulouse LEGOS, Toulouse Cedex 9, France; (2) INRIA, Geostat, Bordeaux, France; (3) University of Heidelberg, Interdisciplinary center for scientific computing, Heidelberg, Germany; (4) IRD, Legos, Toulouse Cedex 9, France

The knowledge of green house gases (GHG) fluxes at the air-sea interface at high resolution is crucial to accurately quantify the role of the ocean in the absorption and emission of GHGs. We present here a novel method to reconstruct maps of surface ocean partial pressure of CO2, pCO2, and air-sea CO2 fluxes at super resolution (4 km) using Sea Surface Temperature (SST) and Ocean Colour (OC) data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). Inference of super-resolution of pCO2, and air-sea CO2 fluxes is performed using novel nonlinear signal processing methodologies that prove efficient in the context of oceanography. The theoretical background comes from the Microcanonical Multiformalism which unlocks the geometrical determination of cascading properties of physical intensive variables. As a consequence, a multiresolution analysis performed on the signal of the so-called singularity exponents allows the correct and near optimal cross-scale inference of GHGs fluxes, as the inference suits the geometric realization of the cascade. We apply such a methodology to the study offshore of the Benguela upwelling system. The inferred representation of oceanic partial pressure of CO2 improves and enhances the description provided by CarbonTracker, capturing the small scale variability. The methodology is validated using in-situ measurements by means of statistical errors. Mean absolute and relative errors in the inferred values of pCO2 with respect to in-situ measurements are smaller than for CarbonTracker. The potential of the approach with other gases such as DMS is illustrated.

### O-1115-05

#### Top down estimates of the European emissions of hydrofluorocarbons and comparison with bottom up inventories

M. Michela (1) ; F. Graziosi, (1) ; U. Giostra, (1) ; J. Arduini, (1) ; F. Furlani, (1) ; P. Bonasoni, (2)

(1) University of Urbino, Basic Sciences and Foundations, Urbino, Italy; (2) National Research Council, Institute for the study of the atmosphere and climate, Bologna, Italy

Hydrofluorocarbons are strong greenhouse gases included in the United Nations Framework Convention on Climate Change (UNFCCC) Kyoto Protocol.

Under the Protocol, Parties are required to submit to UNFCCC their annual emission inventories. Such emissions are annually assessed using "bottom-up" methods aggregating various local statistics. However, emissions measured by their accumulation in the atmosphere, can significantly disagree with reported bottom-up estimates.

Top-down emission estimates based on in situ long-term high frequency observations combined with inverse modelling have proved to be a powerful and important tool for the quantification of emissions and the verification of bottom-up inventories for many trace gases. Here we present regional (European) emission estimates of nine hydrofluorocarbons characterised by extremely high Global Warming Potentials (GWP's).

Emissions estimates are obtained through a combination of observations and models. For this study we used high frequency, long term observations conducted via gas chromatography-mass spectrometry in four WMO-GAW

Global stations in Europe that are part of the AGAGE (Advanced Global Atmospheric Gases Experiment) network. The obtained data undergo a rigorous quality control, following the procedures adopted within AGAGE. FLEXPART 20-d backward trajectories and a Bayesian inversion method then used in order to derive annual emissions from the European Geographic Domain, divided into eight macro-regions, starting from 2001 onward.

Then, we compared our estimates with the bottom-up inventories submitted by the single country to the UNFCCC. Such comparison revealed not negligible discrepancies between the inversion results and the inventories, thus showing the effectiveness of this approach as a verification tool for declared emissions

The estimates provided by this analysis are relevant non only for constraining the atmospheric budget of these gases on a regional scale, but also to improve the accuracy of their emissions quantification on a global scale.

### O-1115-06

#### Observational Determination of Surface Radiative Forcing by CO2 and CH4

W. Collins (1) ; D. Feldman (2) ; MS. Torn (2)

(1) UC Berkeley / Berkeley Laboratory, Earth & Planetary Science / Climate Sciences, Berkeley, California, United States of America; (2) Berkeley Lab, Climate sciences, Berkeley, California, United States of America

Earth's background atmospheric CO2 and CH4 concentrations have been steadily rising due to anthropogenic emissions, and these increases since 1750 have implications for the radiative balance of the Earth's atmosphere. The physics governing how atmospheric CO2 and CH4, both well-mixed greenhouse gases (WMGHGs), influence atmospheric infrared energy balance, and thus climate, are well established, but the impact of recent atmospheric WMGHG trends on the surface energy balance has not been experimentally confirmed in the field.

Using infrared WMGHG absorption bands and controlling for atmospheric temperature and water vapor, spectra from the DOE ARM Program's Atmospheric Emitted Radiance Interferometers (AERI) yield the first direct observational evidence of the time-series of WMGHG surface radiative forcing directly attributable to recent increases in WMGHGs, in this case between 2000-2010. The time-series shows a secular trend of in the radiative forcing from both CO2 and CH4. This data record provides the first comprehensive observational evidence of upward trends in surface radiative forcing by WMGHGs, confirming theoretical predictions of the anthropogenic atmospheric greenhouse effect. These data support predictions of enhancements to the greenhouse effect from future WMGHG emissions.

## 1115-POSTER PRESENTATIONS

### P-1115-01

#### Evolution of CO2 storage in karstic cavities by changes in climate in semiarid regions: Bull Cave (Alicante, Spain)

D. Benavente (1) ; C. Pla (1) ; C. Grossi (2) ; E. Garcia-Anton (3) ; S. Cuezva (3) ; A. Fernandez-Cortes (4) ; S. Sanchez-Moral (3) ; J. Cañaveras (1)

(1) University of Alicante, Earth and Environmental Sciences, Alicante, Spain; (2) University of East Anglia, Norwich, United Kingdom; (3) CSIC, Museo nacional de ciencias naturales, Madrid, Spain; (4) Royal Holloway, University of London, Department of earth sciences, Surrey, United Kingdom

The global carbon cycle in the Earth's surface-troposphere boundary depends on feedbacks among a number of sources and sink processes that operate on both short and long time scales. Soil and subsurface cavities in the vadose zone may contain large amounts of CO2 compared to the exterior air. CO2 concentrations in the vadose zone show significant seasonal and even daily variations, which involves the exchange of large amounts of this greenhouse gas with the lower troposphere. The main source of the CO2 contained in the caves is the organic production from
soil although the abiotic contribution can be important in warm seasons. CO2 from soil can be transported into the caves as a gas or dissolved in seepage waters and the final cave air CO2 concentration air is broadly the result of the mixing of background atmospheric CO2 with soil-produced CO2. Tourism can also increase CO2 concentrations in cave-air by an order of magnitude. The cavities CO2 outputs are mainly due to ventilation processes that depend on cave morphology, the number and configuration of cave openings, and microclimatic relationships with the exterior climate.

Our study has been carried out in the Rull cave during two annual cycles (November 2012 - January 2015). The karstic cavity is located in the northeastern sector of Alicante province, a semiarid region on the Spanish Mediterranean coast (30 km far from the coast line). Indoor trace gases (CO2 and 222Rn) showed that cave acts as both CO2 sink and source for the whole period, although some differences were found between the two registered cycles. For the first cycle (December 2012 - November 2013), average value of indoor T and RH were 15.9°C and 97.2% respectively. Indoor T reached a maximum value of 16.6 °C. CO2 mean concentration was 2054 ppm but this value varied from 463 ppm (minimum value, registered in January 2013) to 4065 ppm (August 2013). In 2014, indoor T and RH average values were 16.1°C and 97.8% respectively but indoor T reached a maximum value of 17.9 °C. Mean CO2 concentration was 1937 ppm but ranged from 565 ppm (February 2014) to 3731 ppm (August 2014). The gaseous recharge of the cavity occurs when the outdoors temperature is higher than the cave air temperature as consequence of the air density differences. For the second studied cycle (2014) the recharge of the cavity took place over 10 days than for the first cycle. Indoor temperature exceeded the temperature of the cavity slightly earlier than in 2013. This fact confirms that relationship between both temperatures is a key factor in the dynamics of this cavity. Furthermore, air cave CO2 changed for the both cycles and was closely related to rainfall since it contributes to biotic and abiotic processes. For the first cycle (2013) total annual rainfall was 471 mm, while it was 280 mm for 2014. Rainfall drop is mainly responsible of a lower CO2 concentration in the cavity for 2014 due to a lower organic production as consequence of reduction in soil moisture; (ii) a lower amount of seepage waters that finally reach the cavity containing dissolved CO2; (iii) when the soil-epikarst system suffers for a reduction in moisture (due to the scarce rainfalls) a major connection between the underground and the exterior environment is accomplished as consequence of an opening of the soil porous system and the fractures-fissures of the epikarst, which is responsible for a higher gaseous exchange.

The isotopic signal δ13C of CO2 is widely used as a proxy of the origin of the CO2. The light values of δ13CO2 inside the cavity point to an organic origin of the CO2. δ13CO2 average annual value for outdoor atmosphere, soil and cave are -10.1, -21.9 and -22.0 % respectively. CO2 in soil was measured for the whole year in 2014. Maximum CO2 (2948 ppm) occur while the cave is in gaseous recharging (April 2014) while the lowest concentration (735.5 ppm) in August 2014, when the soil production is buffered due to the high temperatures and scarce water.

Results highlight the narrow existing dependence between climate conditions and CO2 dynamics in the cave-soil atmosphere system. The outputs of the CMIP5 multi-model ensemble, under the RCP4.5 and RCP8.5 scenarios, predicts a relevant increase of temperature and a decrease in precipitation and relative humidity at the geographical coordinates of the cave surface throughout the current century. We are using this CMIP5 output to model the expected shift in season ventilation-recharge pattern and a potential reduction of the CO2 storage capacity in this semiarid region.

P-1115-02

The use of GHGs as tracers of the coupling/uncoupling between natural processes and human activities in a Mediterranean Delta system

L. Cañas Ramirez (1); E. Vazquez, (1); A. Àgueda, (0); P. Occhipinti, (1); C. Grossi, (1); R. Curcoll (1); M. Nofuentes Ramos (0); O. Batet, (1); S. Borràs, (1); X. Rodó (0); J.A. Morgui (1)

(1) Institut Català de Ciències del Clima, Lab atmosphere & oceans, Barcelona, Spain

Delta ecosystems are important in many environmental aspects as they act like a buffer between terrestrial and marine ecosystems. Moreover, human activities control the basing hydrology and the overall watershed economy from the water in a resource perspective. Furthermore, the Delta environmental patchiness favors a high biodiversity standing on a delicate equilibrium.

The high sensitivity of these ecosystems to small changes in environmental conditions, already under the pressure of human exploitation, might lead to abrupt changes on demographic dynamics of the inhabiting species, the migrant ones and the invasive ones. Under the threats of climate change, like reduced water discharge and the rise of global warming, the increase in temperature, increase in the incidence of droughts, etc., might amplify the effects of natural occurring cycles.

The detailed and continuous study of greenhouse gas emissions (GHGs) like CO2, CH4 and N2O as tracers of ecosystem metabolic fluxes is a useful tool to discern the changes occurring along different temporal scales, from less than 10 years. Thus, they offer an excellent dataset to assess management, adaptation and mitigation policies on endangered debts.

The Ebre River Delta is one of the largest wetland areas (over 300 Km2) in the North-Western Mediterranean region. This area presents a high diversity of ecosystems with rice fields, natural lagoons and marshes along the shoreline, conforming a highly patched landscape. Water management plays a relevant role in agricultural activity, birdlife habitat protection and GHGs sources and sinks.

A GHGs measurement station has been established at the Ebre River Delta Natural Park with the aim of studying climate interactions between land-surface and atmosphere by the Institut Català de Ciències del Clima (IC3) within the framework of the Climadat project (www.climadat.es, funded by Obra Social "La caixa" and InGOS).

GHGs data obtained in this location provide thorough knowledge of the Ebro river delta and the coupling and uncoupling of human activities and natural cycles.

P-1115-03

A dedicated monitoring network for greenhouse gases: SNO ICOS-FRANCE

M. Delmotte, (1); M. Ramonet (1); V. Kazan, (1); C. Vuillemin, (1); PE. Blanc (2); B. Burban (3); S. Conil, (4); A. Diawara (5); F. Gheusi, (6); J.M. Metzger (7); J.M. Pichon, (8) (1) LSCE, Gif-sur-Yvette, France; (2) CNRS, St Michel l'Observatoire, France; (3) INRA, Cayenne, French Guiana; (4) ANDRA, Observatoire pérenne de l'environnement, Bure, France; (5) University Felix Houpouët Boigny - Cocody Abidjan, Physic, Abidjan, Ivory Coast; (6) Laboratoire d'Aérologie, Observatoire midi pyrénées, Toulouse, France; (7) CNRS & Université de La Reunion, Osu-reunion, Saint Denis de la Reunion, France; (8) Laboratoire de Météorologie Physique, Opgc, Clermont-Ferrand, France

Greenhouse gases (GHG) have been identified as the main actors of current climate change. Evolution of the atmospheric composition will drive our future climate and it is therefore essential to increase our knowledge of the global carbon cycle, to refine the carbon budget from global to regional and/or national scale and to precisely monitor the composition of the atmosphere.

Since the pioneer CO2 observation study conducted at Mauna Loa in the late fifties atmospheric monitoring situations have been progressively deployed over most of the earth, mainly focusing on CO2 species. Over the last decade a significant effort has been engaged to build real operational monitoring network including more monitored species (CO2, CH4, CO, N2O) and continuous recording (instead of flasks samples). In Europe, these efforts resulted in the foundation of the Integrated Carbon Observation System (ICOS) research infrastructure which is based on a harmonized and operational monitoring network including 16 countries.

As member and contributor to the ICOS infrastructure, France has a major role on the atmospheric component of the project through the GHG national network (SNO ICOS-France) and the atmospheric thematic center installed
at LSCE. The French monitoring network consists of 12 observation stations including ground stations and a tower equipped with several sampling levels.

We will present the French monitoring network for GHG:

* Network design and station location,

* station set up and specifications,

* instrumental set up and characteristics,

* data treatment and quality control.

We will also give some example of scientific results obtained from chosen observations within the French monitoring network (altitudinal gradients, characteristic synoptic events, trends and seasonal variability on long term records).

## P-1115-04

# Methodological Discrepancies in Measuring Agricultural Greenhouse Gases for Precise Estimation of National Emissions

MI. Khalil (1); B. Osborne (1)

(1) University College Dublin, Ucd earth institute, Dublin 4, Ireland

The main agricultural greenhouse gases (GHGs) – nitrous oxide (N2O) and methane (CH4) – account for 10–12% of anthropogenic emissions globally, corresponding to ~60% and 50% of total anthropogenic emissions, respectively. Agricultural systems are highly diversified and complex, and their measured data covering all practices are very limited to estimated GHG emissions accurately at entity scales/system boudaries and thereby national levels, which is vital. This is to provide robust data for accounting, modeling, finding policy options and mitigation solutions with confidence, leading to achieve environmental sustainability and greater resilience in agricultural production. Special equipment, technical capacity and infrastructure required to measure actual GHG emissions from the source into the atmosphere are insufficient at global scales. These are associated with cost and complexity of methodologies as well as huge difficulty in measurement under field conditions. These result in large uncertainty due to sampling errors and the impact of soil, weather and other environmental variables including management-induced changes relative to background pools and fluxes.

Soil N2O emissions are extremely variable in time and space linking particularly to the practices that affect its fluxes in one soil alone or in association with climate/site-year more than in another. Accordingly, development/selection of existing but globally recognized methodology appropriate for a country should be chosen. It is to estimate changes in emissions accurately at the entity level but sufficiently generalizable for upscaling. There are several existing methods to measure N2O and CH4 emissions for example are: (i) intact soil cores under artificial environment without vegetation and simulated management practices, (ii) closed or open chamber measurements that are limited primarily by timing and frequency of gas sampling, (iii) automated chamber that represents the vegetation canopy and management practices inadequately, (iv) micrometeorological shows difficulty in differentiating the impact of land use and management practices at entity/boundary scales, and (v) isotope technique, which is very delicate and expensive.

Recently, tiered measuring approaches are proposed to capture both temporal and spatial variability of agricultural GHG fluxes including livestock and manure management systems coupling with the generation of ancillary data related to key variables in these systems. For precise estimation at national GHG emissions using practice-based scaling factors, a new hybrid approach i.e. coupling model with a measurement network of stratified monitoring sites with due consideration to key factors for example soil properties, land use type, nutrient and water management and climate influencing GHG emissions is likely to be most feasible and robust way forward to minimize uncertainty. Given the regulatory roles of the key influencing factors and variables, each measurement method has its advantages and disadvantages in providing the quantity of GHG emissions closer to reality. This paper illustrates the above issues to find a universally acceptable

appropriate methodology to accurately measure and monitor GHGs from agricultural systems.

## P-1115-05

# A proposed open international standard for GHG emissions and offsets

L. Mckee (1); D. Bart (2); M. Jackson, (3)

(1) Open Geospatial Consortium (OGC), Wayland, Massachusetts, United States of America; (2) Open Geospatial Consortium (OGC), Antwerp, Belgium; (3) University of Nottingham, Professor of geospatial science, faculty of engineering, Nottingham, United Kingdom

The diversity of carbon calculators, protocols and registries currently makes it difficult to publish, discover, assess, access, aggregate, analyze and share geospatial and statistical information about GHG emissions and offsets. In recent years, facing similar diversity, the hydrology, aviation meteorology, climatology and geology communities have all developed consistent international open geospatial standards (WaterML 2.0, WXXM, netCDF and GeoSciML) for encoding those four types of data. Those standards are based on a shared framework of geospatial and temporal standards that make maximum use of Internet and Web technologies, GHG markets, treaties, science, and taxation and regulator regimes, all await an expansion of that standards framework to encompass GHG emissions and GHG offset projects. International standards for geospatially consistent digital characterization of GHG emissions and offsets would add rigor to GHG science and management analysis and transparency to GHG transactions and compliance. The standards would also increase the value of GHG data by fully integrating computational and communication power of the Internet and Web.

Virtually all of the data involved in GHG measurement and management activities has geospatial and temporal elements. The not-for-profit standards organizations Open Geospatial Consortium (OGC) and World Wide Web Consortium (W3C) are already engaged together along with ISO with many other organizations in developing a unified platform of spatial environmental standards.

We propose that public and private sector climate organizations commit a very small fraction of their budgets to developing open international encoding and interface standards that would enable efficient and effective integration of GHG data. Much of what needs to be measured and communicated has already been captured in current GHG registries, protocols and calculators. The next step is to agree on common conceptual models for this data, using something like UML (Universal Modeling Language) diagrams. There will probably need to be a separate data model for each greenhouse gas, though the models will share many features and borrow significantly from standards such as WaterML 2.0. The conceptual models would provide a basis for different but interoperable implementation standards for computing platforms such as XML, JSON and REST, or CSV.

Our talk, perhaps a keynote, would be focused on standards for encoding GHG data, but it would also show how this proposed standard or set of standards is necessary for all types of environmental accounting. We would explain the methodology for developing such standards and explain why such standards are urgently needed as we enter «the environmental age».

## P-1115-06

# The French ICOS ecosystems stations : an overview

S. Lafont (1); D. Loustau (2); T. Tallec (3); D. Bonal, (4); E. Ceschia (3); A. Chabbi (5); S. Conil, (6); E. Dufréne, (7); S. Garrigues, (8); R. Joffre, (9); K. Klumpp (10); B. Longdoz, (4); B. Loubet, (11); O. Marloie (8); B. Mary, (12)

(1) INRA, Bordeaux-IPSA, Villenave d'Ornon, France;

(2) INRA, ISPA, Villenave d'Ornon, France; (3) CESBIO, toulouse; (4) INRA, Nancy, France; (5) INRA, Lusignan, France; (6) ANDRA, Observatoire pérenne de l'environnement, Bure, France; (7) Université Paris Sud, orsay, France; (8) INRA, Avignon, France; (9) CEFE, Montpellier, France; (10) INRA, Avignon, France; (11) CEFE, Montpellier, France; (12) INRA, Grignon, France
the terrestrial biosphere strongly with the climate, providing both positive and negative feedbacks due to biophysical and biogeochemical processes. To understand and predict the evolution of the climate, it is critical to understand both the contribution of vegetation to the greenhouse gases (GHG) budget and the response of the terrestrial biosphere to the changing climate.

The Integrated Carbon Observation System (ICOS), a new European monitoring network, offers a unique way of documenting and quantifying long term changes in the GHG balance of ecosystems. The ICOS research infrastructure includes atmospheric, ecosystem and marine station networks. The Ecosystem station network (ESN) of ICOS is based on a large number of monitoring stations that will be maintained for the next 20 years. The ESN uses a large set of standardised instruments to perform continuous and intensive measurements of meteorological and micrometeorological variables. A central part of this measurement set is the eddy covariance measurement, that allows a continuous monitoring of the flux exchanged between vegetation and atmosphere. All together these standardised observations allow a better understanding of the functioning of ecosystems in relation to climate and management practices.

ICOS Ecosystems France, the French part of ESN is a cooperation of three research institutes: INRA, CNRS and ANDRA. ICOS Ecosystems France is extensive and includes eight observation stations ( 4 Class 1, 4 Class 2). In addition seven associated stations also contribute to the network. The network samples a wide range of ecosystems (forest, crop and grassland), of management practices and climates (from cold mountain climate to tropical humid in Guyana, including wet oceanic and dry Mediterranean climate).

We will provide an overview of the stations and the measurement system (sensors and data flow). We will equally present the current status of the network, recent measurements and preliminary findings.

## P-1115-07

### Ground-based monitoring of greenhouse gases emissions over continental ecosystems: the ecosystem part of the ICOS European infrastructure

D. Loustau (1); S. Lafont (1); J. Janssens, (2); D. Papale, (3)
; R. Valentini (3); B. Gielen, (2); M. Op De Beek (2); TMT.
Nguyen (2); R. Ceulemans, (2)

(1) INRA, ISPA, Villeneuve d'Ornon, France; (2) University of Antwerpen, Antwerpen, Belgium; (3) University of Tuscia, Viterbo, Italy

Since the discovery in the early nineties of a missing terrestrial sink of carbon in the global carbon cycle (Tans et al. 1990), there was a tremendous effort of observation of the continental part of the carbon cycle.

The most recent estimate of its magnitude proposed by the Global Carbon Project reaches 10.6 GtC CO2±2.9 in 2014. The continental ecosystems contribute to attenuate the anthropogenic greenhouse gases enhancement by 29%.

This terrestrial sink is characterized by the large amplitude of its inter-annual variations and its ample uncertainty which makes it difficult to predict the future of the continental sink of carbon.

Inversion of atmospheric concentrations in greenhouse gases (GHG) and their temporal variations combined with atmospheric transport model allows characterizing the GHG exchanges at the continental surface at typical scale of 10 to 100 km.

Point measurements of the full GHG budget at half hourly resolution together with ancillary measurements on vegetation, management practices and soil permit to characterize the biogeochemical processes involved and their drivers. They are of utmost importance for understanding the GHG cycle and its sensitivity to environmental drivers on the long term.

Thus far, however, the inhomogeneity of methods, protocols and instruments used across ground observation networks have limited strongly our capacity to detect and observe the effects of environmental changes

that are assumed to provoke changes in the GHG cycle. Indeed, the rate of pollutants deposition (Ozone, Nitrogen compounds), solar dimming, climate change and CO2 concentration enhancement not mentioning the secondary drivers are not monitored with sufficient accuracy and neither co-located in a sufficient number of stations for attributing clearly changes in the GHG budget of the main terrestrial ecosystems.

From this conclusion, the European research strategy implemented through the ESFRI roadmap was to build a new world class infrastructure having the capacity to coordinate and harmonise networks of ocean-, atmospheric- and ground-based stations equipped with identical instruments and operated according to the sale common protocols and standards, that is the ICOS infrastructure.

This communication will present the ICOS ecosystem network of stations and the Ecosystem Thematic Centre which collects and processes the measurements that are being operated across the station network. It will give few examples of the data obtained so far and show how they are being used for establishing robust GHG budgets of different ecosystems and their sensitivity to the environment, management practices and interaction.

Le Quéré C. et al. 2014. Global Carbon budget 2014. Earth Syst. Sci. Data Discuss., 6, 1-90, 2014.

Tans, P. P., I. Y. Fung and T. Takahashi (1990). "OBSERVATIONAL CONSTRAINTS ON THE GLOBAL ATMOSPHERIC CO2 BUDGET.» Science 247(4949): 1431-1438.

## P-1115-08

### A Multi-Model Regional Decomposition of CO2 Emissions: Socio-Economic Developments vs Energy Efficiency and Carbon Intensity Improvements

MM. Malpede (1)

(1) Fondazione Eni Mattei (FEEM), Milan, Italy

This study explores the regional distribution of total CO2 emissions.

Kaya and Yokoburi (1997) decompose carbon dioxide emissions into 4 different components, namely Population, GDP per capita, Energy Efficiency and Carbon Intensity.

Ang (2004) shows that a difference in an aggregate indicator can be decomposed into the sum of the effects by differences in explaining factors and residual terms. Therefore changes of CO2 between time t and t-n is defined as the sum of the differences of each of the drivers and a residual term:

By making use of the Long Mean Divisia Index (LMDI) and the Refined Laspeyres Decomposition (RLD), the purpose of the paper is to quantitatively analyze how those components affect total CO2 emissions for different regions of the world, over time and across different socio-economic scenarios. In particular, socio-economic scenarios considered to perform this analysis are the 5 SSPs developed by National Center for Atmospheric Research (NCAR).

The reason of that is to determine the implications of each of the 4 drivers in evaluating the impacts of climate policies on global and regional economic systems and exploring the differences between short-term (2010-2030), medium-term (2010-2050) and long-run (2010-2100) effects.

By drawing data from the ILASA Database, this study considers 6 Integrated Assessment Models used to analyze climate mitigation and impact of different policies in regional economic systems, i.e. AIM-CGE, REMIND, MESSAGE, GCAM, IMAGE and WITCH and by making use of the Principal Component Analysis it evaluates their performances in explaining regional CO2 variations, and in which degree they differ.

The main findings of this study are the following:

**REGIONAL VARIATIONS OF CO2 EMISSIONS:**

- Index Decomposition Analysis, performed by utilizing
the LMDI method suggests a convergence and eventually divergence in total CO2 emissions over time for developing countries with respect to advanced economies. This is mainly due to more robust GDP per capita and Population growth rates relatively to those shown by the USA and Europe.

— However this is not the case of Latin America countries which thank to its relative high rates of carbonization and less GDP per capita will show a minor average growth of total CO2 emissions with respect to that of the USA.

### IMPACT OF EACH FACTOR IN EXPLAINING CO2 OVER TIME AND ACROSS SCENARIOS:

- GDP per capita and Population are shown to have a positive impact on total CO2emissions, in particular for developing regions. Energy Efficiency, in contrast, is the main determinant in dragging down total CO2 emissions variations across different economic scenarios. This is valid for all regions considered expect for Latin America countries in which decarbonization plays the biggest role.

- While the impact of Energy Efficiency is more stagnant over time, the pattern shown by the Carbon Intensity Effect suggests an increasing trend over the course of the years. Nevertheless the implications of such components differ from region to region and scenario considered.

### PERFORMANCES OF INTEGRATED ASSESSMENT MODELS IN EVALUATING REGIONAL CO2 EMISSION VARIATIONS:

- Principal Component Analysis suggests that although the 6 models achieved a considerable degree of homogeneity, the main source of difference stems from the components of Primary Energy (i.e. Fossil, Biomass, Nuclear and Non Biomass Renewables), while showing a similar pattern for Carbon Intensity, Population and GDP per capita. In particular IMAGE and MESSAGE incorporate more optimistic assumptions on total CO2 variation in the short-term relatively to WITCH, GCAM, AIM and REMIND.

## P-1115-09

### Influence of Tropospheric and Stratospheric Air Pollution on Climate Change over the Indian Subcontinent

#### S. Palve (1)

(1) Research Scholar University of Pune, PUNE, MAHARASHTRA, India

India is home to an extraordinary variety of climatic regions, ranging from tropical in the south to temperate and alpine in the Himalayan north, where elevated regions receive sustained winter snowfall. India is characterised by strong temperature variations in different seasons ranging from mean temperature of about 10°C in winter to about 32°C in summer season. Monsoonal and other weather patterns in India can be wildly unstable, ephedra droughts, floods, cyclones, and other natural disasters are sporadic, but have displaced or ended millions of human lives. Ongoing and future vegetative changes and current sea level rise and the attendant inundation of India's low-lying coastal areas are other impacts, current or predicted, that are attributable to global warming. Over the past two decades India has undergone rapid industrial and economic development with increasing emissions of gaseous pollutants. The main tropospheric pollutants (O3, NO2, CO, formaldehyde (HCHO) and SO2) and two major greenhouse gases (tropospheric O3 and methane (CH4)) and important parameters of aerosols, which play a key role in climate change and affecting on the overall well-being of subcontinent residents. In the light of considering these facts this paper aims to investigating possible impact of air pollutants on climate change over the subcontinent. Atmospheric aerosols can impact the local and regional radiation heat budget. Black carbon aerosols absorb incident solar radiation and heat the atmosphere more effectively than dust, sulfates, and organic carbons, which reflect more radiation and cool the atmosphere. The population 1.25 billion in India has led to a significant demand on natural resources. Biofuels such as wood fuel, dung, and crop waste are the primary contributors of aerosols in rural areas of India. Satellite derived column aerosol optical depth (AOD) is a cost effective way to monitor and study aerosols distribution and effects over a long time period. Aerosols have an impact on cloud formation process largely affecting monsoonal rainfall

distribution over Indian subcontinent especially in the Ganga basin. Aerosols are found to be substantially increasing in the Ganga basin. Indo-Asian aerosols have impact on radiative forcing that cause negative forcing (cooling) at surface and positive effect (warming) at top of atmosphere. AOD is found to be increasing rapidly since 2000 in summer season that may cause adverse effect. Increased aerosol loading may likely affect the rainfall which is responsible for the observed drought conditions over the Indian subcontinent. Carbon monoxide is emitted into the atmosphere by biomass burning activities and by various other anthropogenic activities. The MOPITT CO retrievals at 850 hPa show large CO emission from the IG region. MOPITT CO distributions are able to capture at least part of the surface CO pollution, particularly where the sources are strongest in the Indian region. MOPITT CO daytime retrievals are able to provide significant information on the vertical transport of CO associated with the deep convective activities during the Asian Summer Monsoon and horizontal transport during the winter monsoon. The development of convective activity associated with the ASM leads to large scale vertical transport of the boundary layer CO from the Indian region into the upper troposphere. Ozone (O3) plays an important role in the global weather and climate even though the total atmospheric composition of ozone is less than that of other trace gases. The total ozone column (TOC) in the tropical atmosphere depends on both chemical and dynamical processes and has been studied extensively during the past few decades. TOCO over the Indian subcontinent has a systematic and gradual variation, spatial as well as temporal. Higher amount of TOCO in the northern latitudes and simultaneous lower TOCO at near equatorial latitudes indicates depletion of ozone near the equator and accumulation at higher latitudes within the subcontinent. Winds at tropospheric and stratospheric heights may be just one of the principal factors of spatial variation of TOCO that transports atmospheric constituents from one region to another. The Asian monsoon affects the chemical composition of the troposphere. In addition, changes in stratospheric ozone and atmospheric abundances of aerosols alter the energy balance of the climate system.

## P-1115-10

### A Roadmap for Monitoring GHG Emissions Reduction in Brazil

#### M. Poppe, (1) ; M. Rocha, (2)

(1) Centre for Strategic Studies and Management in Science, Technology and Innovation (CGEE), Sustainable development, Brasilia - DF, Brazil; (2) Fabrica Ethica, Piracicaba - SP, Brazil

The Brazilian government is developing and implementing a modular system to monitor, analyze and manage the greenhouse gases (GHG) emissions reductions achieved through the National Mitigation Plans (NMP) - SMMARE (in Portuguese: Sistema Modular de Monitorização e Acompanhamento das Reduções das Emissões de Gases de Efeito Estufa).

Since the NMP are in different stages of implementation and are substantially different in terms of mitigation actions, each NMP will have a Monitoring Module (MM) that will be implemented in different points of time. All MM will be based on the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, taking into consideration relevant national circumstances.

CGEE (a non-profit organization with the mission of rendering Science, Technology and Innovation as Brazil's best allies for economic growth, competitiveness and well-being) has coordinated, under the supervision of the Environmental Ministry, a group of experts with wide experience on national GHG inventory planning, implementation and review, to develop each MM.

SMMARE was conceived during a one-year process with extensive and continuous dialogue with all the Ministries responsible for each NMP; and is being implemented based on 2 scenarios:

* Possible scenario: in which, based on the existing data and/or data that can be easily obtained, the monitoring of GHG emissions reduction could be done in the short-term at the national level;

* Ideal scenario: in which it would be necessary to improve the data collection in order to make the GHG emissions
reduction monitoring in a more disaggregated level (e.g. emissions reduction at the territorial-unit level, due to decrease in deforestation; emissions reduction at the plant level due to implementation of a specific technology; etc.).

Finally, SMMARE is designed to be a tool to help the international consultation analysis (ICA) process to be conducted under UNFCCC, with the aim to increase the transparency of mitigation actions and their effects.

An Example of a Monitoring Module - One of the NMP that have been implemented and is obtaining good results is the Action Plan for Protection and Control of Deforestation in the Amazon (PPCDAm), under the responsibility of the Ministry of Environment. Since its implementation in 2004, deforestation rates in the Amazon region have been decreasing (a 84% reduction in 2012). With the aim of monitoring the GHG emissions reduction associated with the actions implemented by the PPCDAm, a specific MM is being developed based on a generic spatially explicit modeling framework to estimate carbon emissions from deforestation developed by the Brazilian Institute for Space Research (INPE-EM). An indicator for monitoring the GHG emissions reduction achieved by PPCDAm will be tons of CO2 reduced per hectare of avoided deforested areas. Preliminary results indicated that the total potential CO2 emission reduction from PPCDAm could be around 580 million tonnes by 2020, with an average value of 200 tonnes of biomass per hectare.

P-1115-11

Greenhouse gas emissions from energy
consumption and mitigation of a mining
project in Padcal, Benguet Province, Philip-
ines

E. Racelis (1); D. Racelis, (1)

(1) University of the Philippines Los Banos, College of Forestry and Natural Resources, Banos, Laguna, Philippines

The mining industry is one of the most economically important sectors in our society particularly for developing countries. It is a major foreign exchange earner and provides employment opportunities to thousands of people. However, the industry is viewed as among the primary causes of environmental degradation. One of the potential adverse impacts of mining operation is greenhouse gas emission that contributes to global warming and climate change. To minimize the impacts, accurate assessment of greenhouse gas emitting activities is necessary not only to identify them but more importantly to find ways to minimize if not totally avoid their adverse consequences.

A study was conducted to determine the amount of GHG emissions of a mining project focusing on its energy consumption. Using 2014 as base year, the study showed that under Scope 1, the fuel used for both mobile and stationary sources amounted to a total of 5,081,995.10 liters of diesel and 8,317.00 liters of gasoline. The total fuel usage has an equivalent amount of 14,021.09 Mg of CO2e. While under Scope 2, the company consumed a total of 280,142.01 megawatts of electricity in its mine and milling operations including those of ancillary services and staff housing needs. The amount of electricity consumed has an equivalent of 238,400.85 Mg of CO2e emissions.

To sum it up, the company's GHG emissions from energy usage yielded a total of 252,421.94 Mg of CO2e. This would mean that the project has to mitigate its CO2 emissions. One of the easiest and economical ways of sequestering carbon is through plantation maintenance and establishment in which the company has intensively done since then. A Pinus kesiya plantation has an average sequestration rate of 12.7 Mg C ha⁻¹ year⁻¹ or 46.57 Mg CO2 ha⁻¹ year⁻¹ based on studies conducted from different age classes. P. kesiya is a common and most dominant species in the Cordillera Region. Hence, to offset the company's current emissions, it would need a minimum of 5,420.3 hectares of pure Pinus kesiya and mixed P. kesiya plantations to maintain per year. This could also be supported by other mitigating measures to compensate emissions from other sources.

P-1115-12

Interannual variability of atmospheric CO2
and CH4 in Western Europe

M. Ramonet (1); M. Schmidt, (2); M. Lopez, (1); F. Apadula, (3); S. Conil, (4); AH. Elyazidi (1); M. Delmotte, (1); F. Gheusi, (5); M. Laurent, (1); F. Meinhardt, (6); JM. Pichon, (7); G. Sorensen, (8); J. V. Kazan, (9); C. Vulemić, (1) C. Yver-Kwok, (1); JD. Paris, (1); L. Rivier, (1); P. Ciais (1)

(1) LSCE, Cea/cnrs/ulsvq, Gif-sur-Yvette, France; (2) Institut für Umweltphysik, Heidelberg, Germany; (3) Research on Energy Systems, Environment and sustainable development department, Milano, Italy; (4) ANDRA, Observatoire perenne de l'environnement, Bure, France; (5) Laboratoire d'Aérologie, Observatoire midi pyrénées, Toulouse, France; (6) Umweltbundesamt, Kirchzarten, Germany; (7) Laboratoire de Méトérologie Physique, Opog, Clermont-Ferrand, France; (8) National University of Ireland, Galway, Ireland

The space-time variations of trace gases in the atmosphere reflect the distribution of surface emissions, mixed by horizontal and vertical atmospheric transport. By using atmospheric tracers or/and models to quantify the intensity of the mixing, surface emissions can be resolved from the atmospheric measurements. The objective of our study is to characterize the CO2 and CH4 variations observed over Europe. We have analyzed the CO2 and CH4 molar fractions gradients between the continental stations in Western Europe and the Atlantic Ocean. The marine selected data from Mace-Head, Ireland, was used as a reference to define Atlantic Ocean background conditions. Long term (> 10 years) time series of DC02 and DCH4 were calculated from Shauinsland, Plateau Rosa and Puy de Dôme. New monitoring stations set up in France provide a more detailed view of the gradients for the most recent years. The signals are characterized by a high year-to-year variability (up to 6 µmol.mol⁻¹ for CO2), with a strong correlation between most of the stations. The latest winter (2013–2014) shows relatively low gradients at all sites, similarly to 2007–2008 winter season. Both winters correspond to a warm anomaly, associated to stronger Westerlies. Stronger advection and vertical mixing due to higher Westerlies seems to be the main reason for the low gradients observed in 2008 and 2014. However the interannual variability of the climate in Western Europe, also induce variations in the trace gas exchange with terrestrial ecosystems and fossil fuel emissions. The objective of our analysis will be to discriminate between the contributions of atmospheric transport and surface emissions in the observed variability of DC02 and DCH4 over Europe.

P-1115-13

Recovery, recycling and destruction of F-
gases in Georgia

S. Suladze (1); S. Shekeladze (2); L. Kvinikadze (3)

(1) Georgian Refrigerant Recovery and Recycling Centre, Tbilisi, Georgia; (2) Georgian Refrigerant Recovery and Recycling Centre, Tbilisi, Georgia; (3) Tbilisi State University, Tbilisi, Georgia

Introduction of a sustainable system for recovery, disposal and destruction of contaminated artificial refrigerants, which are F-Gases with very high GWP (Global Warming Potential), is a direct contribution to the reduction of emissions of GHG into the atmosphere especially for developing countries.

Refrigerating, Air-conditioning and Heat pump (HRAC) sector is only consumer of industrial GHGs in Georgia. These substances have been widely introduced as alternatives to ODS (Ozone Depleting Substances) refrigerants during the last twenty years since Georgia ratified the Montreal Protocol on Substances that Deplete the Ozone Layer. By this reason annual consumption of the industrial GHGs has grown up sharply and reached over hundred thousand and metric tons now. Therefore the introduction of an effective monitoring system together with recovery, disposal and destruction of F-gas refrigerants is urgent issue today in the country.

This study gives feasibility assessment of such system for Georgia taking into account the experience of the Georgian Refrigerant Recovery & Recycling Centre in recovering, recycling or destruction of the ODS.
In order to make the feasibility assessment the
preconditions for generating unwanted refrigerants bank
were studied.

Based on the gathered and analyzed data the
recommendations were formulated for designing a
sustainable monitoring system of new and used GHG
refrigerant in the country. The recommendations include
an introduction of the refrigerant sustainability
looking at available F-gases waste that can be collected
through two Recovery & Recycling centers operating in
the country in cooperation with service companies, importers,
car dismantling and metal scrapping companies in longer
run with future waste disposal deploying in-country
generated sources of finance.

This is very urgent issue because like in other developing
countries there are no technical facilities of destruction
of F-gases waste in Georgia. So the collected unwanted
GHG refrigerants have to be saved for trans-boundary
transportation where they can be safely destroyed.
Financial mechanism for sustainable system of F-gases
waste permanent collection and destruction has been
studied and shown that several methods for accumulation
of funds inside the country can be acceptable for Georgia.

P-1115-14

Transferring concern with climate mitigation to Institutional Sustainability: A case study applying carbon accounting as a tool for resource management in a desert environment

(3) Tarabieh (1) ; R. Tutwiler (2) ; T. Jaskolski (2) ; M. Rauch (3)

(1) The American University in Cairo, Construction and Architectural Engineering Dept, New Cairo, Egypt; (2) The American University in Cairo, Research institute for a sustainable environment, New Cairo, Egypt; (3) The American University in Cairo, Sustainability office, New Cairo, Egypt

As a result of climate change and the potential risk of
green warming, an emerging interest across academic
institutions to develop a comprehensive inventory of
greenhouse gas emissions is on the rise. Higher education
institutions are often faced with the challenge to develop
a process that will accurately assess the campus' resource
consumption in a timely, economical, and informative
manner. This type of assessment is not typical and relies
heavily on the availability of data and institutional capacity
to carry such exercise accurately and report the findings,
benchmark against peer institutions and establish the
institutional mechanisms to sustain this type of data
intensive work. In response to the previous principals
and faced with a number of environmental challenges
in a desert environment, the American University in
Cairo (AUC) recently completed the first phase of carbon
accounting and issued a Carbon Footprint Report which
highlights the strategies adopted by the sustainability
team to reduce energy consumption on campus. The
report measured the University's carbon footprint, which
is the annual total of carbon dioxide (CO2) and other
significant greenhouse gases emitted into the atmosphere
as a result of daily activities and campus operations. AUC
was the first higher education institution in the Middle
East and North Africa to conduct such a comprehensive
study of its own impact on climate change. As part of its
ongoing efforts to maintain and improve its operational
sustainability, AUC has witnessed a one-third reduction
in overall energy consumption on the New Cairo campus
over the past two years, decreasing the cost of utilities
by 35%, thanks to an energy-saving plan designed and
implemented by the University's sustainability team. This
proposal presents the method, challenges, strengths and
areas of improvement of the method used and outlines
the present strategies developed to manage the campus
resources as a result of this exercise. It also presents the
efforts taken to institutionalize the method so it becomes
campus culture and to transition the work from research
to a daily practice.

P-1115-15

Assessing the role of megacities on atmospheric CO2: results for Paris from the CO2-MegaParis project, France

I. Xueref-Remy (1) ; E. Dieudonné, (1) ; C. Vuillemin, (1) ; M. Lopez, (1) ; C. Lac, (2) ; M. Delmotte, (1) ; F. Ravetta (3) ; O. Perrussel (4) ; F.M. Bréon (1) ; G. Broquet, (1) ; M. Schmidt, (5) ; F. Chevallier (1) ; V. Masson (2) ; P. Ciais (6) ; M. Ramonet (1) ; C. Ampe, (7) ; L. Ammoura, (6) ; V. Gros (1) ; A. Baudic, (1) ; B. Bonsang, (1) (1) LSCE, net-sur-Yvette, France; (2) CNRM, Toulouse, France; (3) LATMOS, Ipsl, Paris, France; (4) AIRPARIF, Paris, France; (5) IUP, Heidelberg, Germany; (6) LSCE, Ipsl, Gif sur Yvette, France; (7) Airparif, Paris, France

On average, atmospheric CO2 increases in the atmosphere at a rate of about 2 parts per million (ppm) per year, due to the accumulation of about half of the anthropogenic CO2 emissions in the atmosphere (mostly from the combustion of fossil fuels) which is about 1/3 of the total. This is because CO2 is re-absorbed by the ocean and the continental biosphere. Today, more than 70% of global fossil-fuel CO2 emissions come from punctual sources such as megacities. Paris is the third megacity in Europe and it emits about 15% of the total French emissions, while it covers only less than 2% of the national territory. Currently, most of the estimates of urban CO2 emissions are given by bottom-up CO2 emissions inventories, which rely on activity proxies and benchmarked emission factors. The associated uncertainties can be as high as several tenths of percent, especially when it comes to discriminate the CO2 urban emissions by emission sectors. Therefore, there is an urgent need for developing new methods to better Monitoring, Reporting and Verifying (MRV) CO2 emissions from megacities, dedicated to provide robust results to policy makers for taking efficient decisions and actions in matter of controlling CO2 anthropogenic emissions and mitigating climate change. Since 2009, the CO2-Megaparis project aims to quantify CO2 emissions from Paris using top-down approaches based on a synergy between atmospheric observations and modeling. For the first time, a mini-network of 3 greenhouse gases (GHG) monitoring stations was developed by LSCE in Paris agglomeration within the infrastructure of the regional air quality monitoring agency, AIRPARIF, completing 2 other GHG stations from the ICOS European greenhouse monitoring network. One of our urban station was located on top of the Eiffel tower above Paris megacity. The analysis of one year of data showed that Paris CO2 emissions lead to a mean increase of the atmospheric CO2 concentration in the mid-afternoon of 2 to 3 ppm, and is strongly seasonal, windspeed and wind direction dependent: the CO2 urban plume is characterized by a very large spatio-temporal variability and can reach about 60 ppm at low windspeeds on top of the Eiffel tower. In addition, analysis of correlations between CO2, CO1 and 14CO2 were carried out from field measurements and allowed an independent assessment of the inventories emission sectors. Furthermore, direct modeling of CO2 at a very fine resolution (2x2 km2, 1h) was performed and matched well with the observations. Last but not least, inverse modeling efforts at the same resolution allowed a significant improvement of the regional inventory from Airparif. Finally, a campaign conducted during springtime and based only on lidar facilities revealed that due to the effect of the urban heat island, the boundary layer height (that can be seen on the first degree as the man dilution factor of CO2 emissions in the atmosphere), is 10 to 40% time higher in Paris than in surrounding rural areas: this is an important result that supports the implementation of urban canopy models in future fine scale urban CO2 modeling framework. A synthesis of the different results will be presented, as well as an attempt of defining the strengths and weaknesses of the atmospheric approach to quantify urban CO2 emissions. Contributions from sister studies (MultiCO2 - IPSL, Le CO2 parisien - Ville de Paris 2030, CarboCount-City - KIC Climat...) will also be mentioned.
# 1116 - Biogeochemical Feedbacks to Climate Change

## ORAL PRESENTATIONS

### K-1116-01

#### Observational constraints on biogeochemical feedbacks

**C. Le Quéré (1)**

(1) University of East Anglia, Tyndall Centre for Climate Change Research, Norwich, United Kingdom

Tremendous efforts are underway to use a wider range of observations to inform model projections. Efforts range from enhanced coordination of repeat observations, the collection of quality controlled data in public databases, the development of new data interpolation methods, and extensive model-data comparison efforts. This presentation will provide an overview of efforts by the carbon cycle research community to constrain, using a range of observations, our quantitative understanding of how the carbon cycle works. It will use the trends and variability observed during 1959-2014 in a range of observations to examine how the land and ocean carbon sinks have responded to changes in increasing atmospheric CO2 and climate change and variability at the global and regional level, and comment on the qualities and limitations of models to project changes in the 21st century and beyond. This presentation will be based on the 'Global Carbon Budget' annual update by the Global Carbon Project. It includes an assessment of the annual increase in carbon dioxide from three ocean data products, seven ocean models, eight dynamic global vegetation models, three atmospheric inversions, plus indirect constraints from CO2 emissions and measured atmospheric CO2 growth rate. The presentation will also include additional data and model analysis from the marine environment and discuss the marine biogeochemical feedbacks related to ocean deoxygenation and to the response of marine ecosystems to climate change and ocean acidification.

### K-1116-02

#### Projecting the carbon-climate feedback from thawing permafrost

C. Koven (1); P. Ciais (2); J. Harden (3); G. Hugelius (4); P. Friedlingstein (5); DM. Lawrence (6); D. Mcguire (7); WJ. Riley (8); C. SchaeDEL (9); E. Schuur (10); G. Grosse (11)

(1) Lawrence Berkeley National Laboratory, Berkeley, CA; United States of America; (2) LSCE, CEA, CNRS and UVSG, Gif-sur-Yvette, France; (3) United States Geological Survey, Menlo Park, CA, United States of America; (4) Stockholm University, Department of physical geography and quaternary geology, bolin centre of climate research, Stockholm, Sweden; (5) University of Exeter, Exeter, United Kingdom; (6) National Center for Atmospheric Research, Boulder, United States of America; (7) United States Geological Survey, Fairbanks, AK, United States of America; (8) Lawrence Berkeley National Laboratory, Climate and carbon sciences, Berkeley, United States of America; (9) Northern Arizona University, Center for ecosystem science and society, Flagstaff, United States of America; (10) Northern Arizona University, Department of biological sciences, Flagstaff, AZ, United States of America; (11) Alfred Weger Institute, Helmholtz centre for polar and marine research, periglacial research unit, Potsdam, Germany

The loss of carbon from ecosystems as they adjust to a warmer climate may act to amplify climate change. Permafrost-affected ecosystems may be particularly vulnerable to such carbon losses because of the huge amounts of organic carbon that have been preserved in frozen soils, which may thaw and decompose more rapidly as a result of climate warming. In the IPCC fifth assessment report, the models of the Earth system were used to estimate the magnitude of these terrestrial carbon-climate feedback processes did not include key representation of the CO2 and CH4 release from permafrost thaw. Recent progress has been made to synthesize observations of permafrost carbon dynamics and develop the representation of these processes in global carbon cycle models, to better estimate the amount and timing of

greenhouse gas emissions from permafrost. I will discuss a variety of approaches to project the feedback from warming permafrost, from highly simplified and data-constrained soil models to detailed ecosystem models that include vegetation-permafrost-nutrient interactions. Such approaches suggest that the carbon-climate feedback from permafrost is an important process on the 50-300 year timescale, and that the magnitude of ecosystem carbon losses is highly sensitive to the future trajectory of fossil fuel emissions, with much larger losses under high emission scenarios such as RCP8.5 than on mitigated emissions pathways such as the RCP4.5 scenario.

### K-1116-03

#### Biogeochemical feedbacks to climate change: Insights into soil moisture controls on soil heterotrophic respiration

**C. Chenu (1); F. Moyano (2); P. Garnier (3); I. Virto (4)**

(1) Agroparistech, Umr ecosys, Grignon, France; (2) CNRS, Bioemco, Grignon, France; (3) INRA, Umr ecosys, Grignon, France; (4) Universidad Pública de Navarra. Escuela Superior de Ingenieros Agronómicos, Departamento de ciencias del medio natural, Pamplona, Spain

Soils contain the largest C terrestrial pool and even small changes in soil organic C (SOC) can have a significant impact on the atmospheric CO2 concentration. The C cycle feedback to climate will largely depend, in magnitude and timing, on the response of soil C to climate changes. However, there is still considerable uncertainty regarding such effects.

While the effect of temperature on soil C mineralization has been the subject of much work and considerable debate, much less attention has been paid to the effect of changes in water regime, another predicted component of climate change. However, soil moisture has a key role in regulating soil respiration. Here, we synthesise work regarding the relation between soil moisture and soil C dynamics, focusing on the underlying mechanisms, on the interaction with soil properties and other components of global changes, and discuss how mechanisms and the complexity of soils can be integrated into models.

The effect of soil moisture is complex to predict because, unlike that of temperature, it is strongly dependent on soil characteristics. Soil moisture effect on heterotrophic respiration is represented in most current carbon cycle models by empirical functions, which are often based on limited experimental data. We performed a data-driven analysis of soil moisture respiration relations and showed how these are consistently affected by soil properties such as clay content, organic C content, bulk density. We developed empirical models including the effects of soil texture, soil organic carbon and bulk density which improve the functions currently used in different soil biogeochemical models.

Partially responsible for the present state of knowledge may be the idea that, in biogeochemical models, time- and spatially averaged or approximate relationship of microbial activity with moisture is sufficient to reliably predict C fluxes. But soil microorganisms live in a complex 3-D framework of mineral and organic particles defining pores of various sizes, more or less inter-connected, which result in a variety of microstructural properties. Most promising perspectives in this area are based on mechanistic approaches, where theoretical linkages between substrate and gas diffusivity in soil pores and heterotrophic respiration are explored in different soil matrices. A new generation of biogeochemical models is based on an explicit representation of soil architecture at a fine scale, which provides in-depth mechanistic understanding, and should help to define relevant descriptors of soil characteristics to improve how relevant scale models account for the effects of soil moisture.

The complex interplay between biological, biogeochemical and physical processes is apparent when considering the variability of soil C storage upon a widely used cropping practice: not tillage, where soil moisture also regulates the flows of C between soil litter and mineral layers. The interactions between soil moisture and other components
of global change, i.e. land use, cropping practices, temperature, will also result in biogeochemical feedbacks to climate change.

## O-1116-01

### Positive future climate feedback due to changes in oceanic DMS emissions

J. Tjiputra (1); K. Six, (2); Ø. Seland (3); C. Heinze (4)

(1) Uni Research, Uni climate, Bergen, (2) Max Planck Institute for Meteorology, Hamburg, Germany;
(2) Norwegian Meteorological Institute, Oslo, Norway; (3) University of Bergen, Geophysical institute, Bergen, Norway

The global ocean is the largest natural source of dimethylsulphide (DMS) gas to the atmosphere. DMS is produced by phytoplankton and is released to the surface ocean if cells are degraded. Once it enters the atmosphere, it might contribute to the nucleation particles important for cloud formation, which then effect the Earth's radiation budget and climate. Future global warming and ocean acidification is projected to alter marine DMS production and emission. However the none of the models assessed in the last IPCC report includes the DMS-climate feedback.

Recent study indicated that under high CO2 emissions future, the oceanic DMS emission is projected to decrease by 12 to 24% by the end of this century, potentially leading to an equilibrium temperature response of 0.1K to 0.76K.

Here, for the first time using a fully interactive Earth system model including a microphysical aerosol module with sulfur chemistry, we perform simulations on future climate projection with coupled DMS feedback. Under the highest pH sensitivity, our simulation shows that projected DMS production and emission decrease relative to the preindustrial state by 50% and 36%, respectively toward the end of the 21st century under the RCP8.5 emissions scenario. The largest emission reduction is simulated in the Southern Ocean. On contrast, emissions at polar latitudes increase owing to the sea ice retreat. This large global change in marine sulfur emission leads to an additional global warming of 0.3K relative to the reference simulation without DMS-climate feedback at the end of the 21st century. Both simulations also produce similar trajectories in atmospheric CO2 concentration, consistent with little change in the cumulative oceanic and terrestrial carbon sinks.

## O-1116-02

### How much carbon dioxide and methane will be released from thawing permafrost soils?

I. Hartley (1); C. Estop Aragones (1); M. Cooper (1); J. Fisher (2); C. Schaedel (3); L. Street (4); A. Thierry (5); D. Charman (1); M. Garnett (6); J. Murton (7); G. Phoenix (2); P. Wooley (4); M. Williams (5); E. Schuur (8)

(1) University of Exeter, Geography, College of Life and Environmental Sciences, Exeter, United Kingdom; (2) University of Sheffield, Animal and plant sciences, Sheffield, United Kingdom; (3) Northern Arizona University, Center for Ecosystem Science and Society, Flagstaff, AZ, United States of America; (4) Heriot Watt University, School of life sciences, Edinburgh, United Kingdom; (5) University of Edinburgh, School of geosciences, Edinburgh, United Kingdom; (6) NERC Radiocarbon Facility, Glasgow, United Kingdom; (7) University of Sussex, Geography, Chichester, United Kingdom; (8) Northern Arizona University, Department of biological sciences, Flagstaff, AZ, United States of America

High northern latitudes are predicted to warm rapidly during the 21st century. The tundra, boreal forests and peatlands found in these regions are recognised to contain substantial stores of organic matter. Permafrost soils are particularly important in this context, storing as much carbon as all the rest of the world's soils put together, and more than twice as much carbon as the atmosphere. The IPCC AR5 report emphasises that there is high confidence that warming in the Arctic and Boreal will lead to a reduction in permafrost extent. However, while some estimates suggest that the potential for carbon release from thawing permafrost soil could be the single most important climate-carbon cycle feedback, the AR5 report also emphasises that there is low confidence in predicting rates of soil carbon loss, and also whether the carbon will be released mainly as carbon dioxide or the more powerful

greenhouse gas, methane. Importantly, the permafrost feedback is not currently included in the models evaluated in the IPCC CMIP programme, and thus a potentially critical feedback is missing.

This presentation will focus on how recent studies, making detailed in situ observations, and running manipulative field and laboratory experiments, have improved understanding of the permafrost feedback. In particular, the presentation will: 1) explain the role of different high-latitude plant communities, including understudied groups such as mosses, in both controlling rates of thaw and potentially mitigating against some of the expected carbon release, 2) outline the important role radiocarbon dating has played in detecting the contribution of the decomposition of old, previously-frozen organic matter to rates of carbon release following permafrost thaw, and 3) discuss the potential for substantial amounts of permafrost carbon to be released in the form of methane.

Research has shown that in boreal forest, thick moss layers may insulate soils to such an extent that disturbances (e.g. fire) may be required before warming promotes deep permafrost thaw. Therefore, tundra and peatland ecosystems may thaw more rapidly due to wetter conditions or reduced thickness of insulating moss layers. Overall, it appears that there is indeed considerable potential for increased carbon dioxide production from thawing permafrost, especially from highly organic soils, and where soils are not permanently waterlogged post thaw. The latter issue requires a fuller consideration of water flow paths within permafrost landscapes. Given the potential for large soil carbon losses, it may be unlikely that these could be fully compensated for by increased plant growth, at least in tundra ecosystems where plant biomass is low. However, through the remaining plant potential for increased soil carbon inputs from plant decomposition, the loss of soil carbon losses. On the other hand, rates of methane production from thawing permafrost may not be as high as first predicted. Rather, the direct effect of climate warming on rates of methanogenesis associated with the decomposition of contemporary carbon inputs in northern wetlands, is likely to be more important.

The permafrost feedback remains potentially one of the most important carbon cycle feedbacks to climate change, but requires considerable further study. Improving understanding of the proportion of previously-frozen organic matter that will decompose aerobically following thaw, and the extent to which nutrient release from thawing permafrost can increase plant growth and soil carbon inputs, should be considered as only ongoing research priorities.

## O-1116-03

### Biomass burning in northern sub-Saharan Africa and associated changes in environmental and climate variables

C. Ichoku (1); L. Ellison (2); C. Gatebe, (3); R. Poudyal, (2); T. Matsui, (4); E. Willmott, (5); T. Gabbert, (6); J. Wang, (7); Y. Yue, (7); R. Damoah, (3); J. Lee, (8); J. Adegoke, (8); J. Bolten, (1); F. Pollicelli, (1); E. Wilcox, (9); F. Hosseinpour, (9); S. Habib, (1); C. Okonkwo, (10); F. Engelbrecht, (11)

(1) NASA Goddard Space Flight Center, Earth sciences division, code 610, Greenbelt, MD, United States of America; (2) NASA Goddard Space Flight Center, Science systems & applications, inc. (ssai), Greenbelt, MD, United States of America; (3) NASA Goddard Space Flight Center, Universities space research association (usra), Greenbelt, MD, United States of America; (4) NASA Goddard Space Flight Center, Earth system science interdisciplinary center (essic), Greenbelt, MD, United States of America; (5) Vanderbilt University, Nashville, TN, United States of America; (6) South Dakota School of Mines & Technology (SDSTM), Rapid City, SD, United States of America; (7) University of Nebraska, Lincoln, NE, United States of America; (8) University of Missouri, Kansas City, MO, United States of America; (9) Desert Research Institute (DRI), Reno, NV, United States of America; (10) Howard University, Washington, DC, United States of America; (11) Centre for Scientific and Industrial Research, Natural resources and the environment, Pretoria, South Africa

One of the most vulnerable tropical regions of the world is the northern sub-Saharan Africa (NSSA) region, which is bounded on the north and south by the Sahara and the Equator, respectively, and stretching East-West across Africa. This is so because of the highly active
carbon needs to be included when assessing targets for
stabilisation and developing policies designed to avoid
dangerous climate change.

P-1116-04

Is Ocean really a source to atmospheric
CO2 during cyclones in the Arabian Sea ?

K. Chakraborty (1); S. Prakash (2); A. Paul (2)

(1) Indian National Centre for Ocean Information Services (INCOIS), Information Services and Ocean Sciences Group (ISG), Hyderabad, India; (2) Indian National Centre for Ocean Information Services (INCOIS), Information services and ocean sciences group, Hyderabad, India

The enhanced biological production, and associated
regeneration, leads to higher pCO2 in the sea water
compared to atmosphere and ocean becomes a source of
atmospheric CO2 (Sarma et al., 2008) during such events.
Cyclone induced productivity intensify this source. Byju et al.,
(2011) reported that Phyan associated net CO2 flux
to the atmosphere was 0.123 Tg C. We have employed a
coupled 3-D bio-physical model, ocean general circulation
model ROMS with an ecosystem model, to study whether
Ocean is really a source to atmospheric CO2 during
cyclones in the Arabian Sea. It is observed that the storm
has a significant effect on the thermocline and mixed
layer depth which in-turn enhance ocean surface chlorophyll
concentration. Model generated sea surface chlorophyll
concentration during several extreme events is validated
using satellite derived ocean colour data which also
shows higher concentrations of chlorophyll in the storm
influenced region. The high concentration of chlorophyll
appeared as a bloom over an area of approximately 150
km in diameter along the storm passage. It is observed
that thermocline shopped up after the storm passed and
this sholing of the thermocline caused entrainment of
nutrients in upper 50 meters which triggers high biological
productivity. The 50 meter vertically integrated primary
production during three different cyclones (Cyclone
01A, Tropical storm 05A and Tropical Storm PHYAN)
was estimated in terms of carbon using the model along
the track of the cyclone/storm. The net sequestration of
carbon due to the above mentioned cyclones are 0.125
Tg C, 0.16 Tg C and 0.125 Tg C, respectively. Our study,
in conjunction with Byju et al., suggest that ocean is not
a source of CO2 to the atmosphere during cyclones but
more such study is required to ascertain whether the
ocean acts as a sink during such events.

P-1116-05

The great climate change and the fuzzy C
sink: how irrigation can change soil carbo-
nates dynamics

Is. De Soto (1); I. Virto (1); P. Barré (2)

(1) Universidad Pública de Navarra. Escuela Superior de
Enginyeros Agrónomos, Departamento de Ciencias del
Medio Natural, Pamplona, Spain; (2) PSL Research University,
Laboratoire de géologie de l'ens, Paris, France

There are two types of carbonates in soils: lithogenic or primary carbonates, and pedogenic or secondary carbonates. The formation of the later depends on the availability of bicarbonates (HCO3−) and cations in the soil solution. When bicarbonates present in the solution are the result of the dissolution of CO2 from soil respiration, the formation of pedogenic carbonates can be considered a net CO2 sink. Carbonates dynamics in soil are however complicated to depict because in addition to the sources of carbonates (which can include pre-existing carbonates, bicarbonates dissolved in incoming water and the soil (atmosphere) and cations), the conditions for precipitation and/or dissolution and leaching are continuously changing. From a global perspective, these conditions can be considered at steady state in a given place when relatively long periods of time (f.e. one year) are considered, and local climate and soil conditions do not change.

However, when the annual soil water balance changes,
alterations in soil carbonate concentrations can be
expected in a short period of time because of the solubility
of carbonate minerals. In this context, human-induced
changes, such as the implementation of irrigation, can
accelerate the dissolution and precipitation cycles of
soil carbonates. In addition, irrigation stimulates the soil

biological activity and biotic CO2 generation and also
irrigation water can be an external source of cations and
bicarbonates. For this reason, studying the evolution
of carbonates in dryland agricultural soils converted to
irrigation can help to understand the extent of this change
in terms of carbonates dynamics. The complexity of these
biogeochemical interactions makes modelling a useful and
interesting tool.

The purpose of this work was to evaluate the variations of carbonate concentrations in the topsoil of a semi-arid Mediterranean agricultural soil after the implementation of irrigation. Two adjacent plots were selected for this study: one under dryland conditions with wheat since at least 50 years and another under irrigation conditions with corn for 7 consecutive years. The plots were located in the same soil unit (Calcic Cambisol) in Funes (Navarra, Spain). Numerical simulations of carbonates concentration, dissolution and precipitation were performed with PHREEQC for the evaluation of the geochemical interactions between the soil, the soil solution and irrigation water, for a simple model based in the monthly water balance and the observed concentrations in the soil solution and irrigation water. In addition, a sensitive analysis was developed in order to investigate the potential impact of the type of crop, salt concentrations in the irrigation water and partial CO2 pressure due to soil respiration. Finally, for the validation of the model, samples of the irrigated and non-irrigated plots were analyzed for their carbonate content and isotopic composition (δ13C).

Simulated values were consistent with the observed values of carbonates concentrations and isotopic signature of the soil samples. The simulation results also suggested that the amount of new precipitated carbonates and the amount of carbonates dissolved in the soil solution in the irrigation water, the partial CO2 pressure and the type of crop. The most sensitive parameter was the partial CO2 pressure of the soil solution. The modelling results showed annual values of carbonates-C leaching around hundreds of kg/ha in the studied area under irrigation.

This study showed that in a relatively short period of time
(seven years) the differences observed in the inorganic C
budget of the agricultural soil studied could be significant
in relation to the total soil C budged. Irrigation could
therefore have an important effect in soil fractions
of carbonate-rich soils and this should be taken into
consideration in regional-scale studies.

P-1116-06

The long-term effect of short-lived species
through the climate-carbon feedback

T. Gasser (1); P. Ciais (1)

(1) LSCE, Gif-sur-Yvette, France

This work aims to quantify and discuss the impact of
short-lived species on the carbon-cycle and through the
climate-carbon feedback. It proceeds in three steps.
First, we isolate the climate-carbon feedback and its
contribution to the currently observed, human-driven,
change in atmospheric carbon dioxide. Second, we
attribute this feedback to its various anthropogenic causes
following the concentration-based attribution of radiative
forcing provided by the IPCC. To do so, we updated the
compact Earth system model OSCAR to its version 2.2, and
we use it combined with attribution algorithms developed
in relation to the Brazilian Proposal (Trudinger and Enting,
2005; doi: 10.1007/s10584-005-6012-2).

In the first step, the model is used as a carbon-cycle
model in which the sensitivity of the ocean and land
modules were calibrated on complex three-dimensional
models used in CMIP5 (Arao et al., 2013; doi:10.1175/
JCLI-D-12-00494.1). Using three historical drivers: (1)
anthropogenic CO2 emissions from fossil-fuel burning, (2)
land-use and land-cover changes, and (3) reconstructed
climate, the historical change in atmospheric CO2 is
shown to be satisfactorily reproduced by the model. This
change in atmospheric CO2 is then attributed to the three
drivers. As best guesses, we find that the observed 2008
burden increase of 107 ppm is attributed at 56% to fossil-
fuel emissions, at 28% to land-use activities, and at 16%
to climate change.

In the second step, we expand the model with a climate
module whose global and local responses to radiative
forcing are also calibrated on CMIP5 outputs (Geoffroy
et al., 2013; doi:10.1175/JCLI-D-12-00195.1). Using
the radiative forcing timeseries produced for the fifth IPCC report (Myhre et al., 2013), we repeat the previous experiment, albeit this time the contribution of «climate change» is further broken-down into contributions by the various primary and secondary radiatively active species: CO₂, non-CO₂ greenhouse gases, ozone or aerosols. Of the 17 ppm (= 16% of 107 ppm) previously attributed to climate change, we estimate 79% are caused by non-CO₂ greenhouse gases, -57% by short-lived species (ozone and aerosols), and the complementary 78% by CO₂ itself.

The overall negative figure from short-lived species is explained by the dominance (among the various effects of these species) of the cooling effect of aerosols. Over the historical period, we show that this cooling avoided a reduction in the carbon sinks efficiency that would have been seen if only CO₂ and non-CO₂ greenhouse gases had been emitted. To complete this analysis, we make a third experiment with a slightly altered model designed to keep track of past changes in the carbon-climate system. This «book-keeping» approach shows that past emissions of short-lived species still have an impact on present-day atmospheric CO₂, and thus on present-day climate. For instance, we estimate that sulfur emissions from the 1980s have an impact of about -2 ppm over the 107 ppm observed in 2008.

To conclude, this study quantifies one of the indirect biogeochemical effect of aerosols (and ozone), as first introduced by Mahowald (2011; doi:10.1126/science.1207374). It provides an emission-based analysis of the causes of the change in CO₂ atmospheric concentration (and thus of its radiative forcing), similarly to what was done for CH₄ or O₃ in the last IPCC report (Myhre et al., 2013). The emission-based approach complements the «traditional» concentration-based one, since it has the interest of providing a diagnosis of the anthropogenic drivers of climate change that is one step closer to the political decision, albeit at the cost of an increased uncertainty as we will also show.

P-1116-07

## Response of Soil Carbon Storage to Temperature and Carbon Input Variability in Earth System Models

K. Georgiu (1); Wj. Riley (2); MS. Torn (3)

(1) University of California, Berkeley, Chemical and Biomolecular Engineering, Berkeley, CA, United States of America; (2) Lawrence Berkeley National Laboratory, Climate and carbon sciences, Berkeley, CA, United States of America

Soil comprises the largest terrestrial carbon pool, containing more than double the carbon currently in the atmosphere and triple that in vegetation. Soil organic matter (SOM) is particularly vulnerable to environmental change, with potential carbon-climate and carbon-concentration feedbacks resulting from soil warming, CO₂ fertilization, nitrogen (N) enrichment, and precipitation. These changes are expected to influence SOM decomposition and stabilization processes, thereby threatening the soil's capacity to serve as a carbon (C) sink. Earth system models (ESMs) currently use linear kinetics to represent soil C dynamics, and therefore lack explicit representation of the non-linear biotic and abiotic mechanisms that govern soil processes. As such, ESMs exhibit high uncertainty in their simulated current and future soil C storage. Recent studies have shown that explicit representation of microbial and mineral interactions improve estimates of current global C stocks and better capture spatial heterogeneity. These microbe-enabled SOM models also better represent non-linear responses to changes in soil temperature and C inputs (e.g., priming and SOM in response to increased soil C inputs) that have been observed in many field and laboratory experiments.

Although recent work has explored the feasibility of incorporating microbial and mineral mechanisms into SOM models within ESMs, most of these models lack explicit representation of nitrogen cycling (nitrogen and phosphorus) and seasonal variability (temperature, C inputs, and moisture). Omitting nitrogen cycling significantly affects simulated global priming responses to elevated CO₂ concentrations, as nitrogen availability plays an important role in dictating microbial activity in nutrient-constrained environments. Thus far, microbe-enabled SOM models within ESMs have also largely ignored the effect of temporal forcing on soil C dynamics, representing seasonal and diurnal temperature, C and N inputs, and

moisture with annual averages. These simplified model input assumptions, however, omit the seasonal and inter-annual fluctuations that microbial communities undergo in response to environmental conditions, greatly affecting the prediction of soil C equilibria and dynamics in ESMs. For example, a significant amount of soil respiration can occur during winter, while soils sampled in the summer (with different microbial composition) do not show respiration at winter temperatures. Leaf litter (primarily in the season) and plant exude of temperature and the C and N inputs greatly impact the magnitude and sign of model response to climate change. We incorporate a trait-based, microbial-mineral, SOM model into the vertically-resolved Community Land Model (CLM4.5) of the Community Earth System Model (CESM) and present simulated current and future global C stocks that result from including seasonal forcing. We explicitly represent microbial diversity and physiology in our SOM model, allowing microbes with distinct temperature and C input optima to dominate decomposition at different times of the year when forced with seasonal temperature and C inputs from CLM4.5. We show that this temporal variability plays an important role in the diverse responses attained at sites with similar mean annual temperatures, but very different seasonality. The results of our vertically-resolved model also show that surface and deep soils' distinct diurnal and seasonal temperature fluctuations greatly affect their respective C storage capacity and vulnerability to global warming. We compare our model to the conventional SOM model within the CESM and to global observations from the Harmonized World Soil Database, and discuss improvements in estimating global and regional C storage and their response to anthropogenic climate change.

In this study we demonstrate that the frequency at which the system is resolved matters, i.e., that the seasonality and magnitude of temperature and the C and N inputs greatly impact the magnitude and sign of model response to climate change. We incorporate a trait-based, microbial-mineral, SOM model into the vertically-resolved Community Land Model (CLM4.5) of the Community Earth System Model (CESM) and present simulated current and future global C stocks that result from including seasonal forcing. We explicitly represent microbial diversity and physiology in our SOM model, allowing microbes with distinct temperature and C input optima to dominate decomposition at different times of the year when forced with seasonal temperature and C inputs from CLM4.5. We show that this temporal variability plays an important role in the diverse responses attained at sites with similar mean annual temperatures, but very different seasonality. The results of our vertically-resolved model also show that surface and deep soils' distinct diurnal and seasonal temperature fluctuations greatly affect their respective C storage capacity and vulnerability to global warming. We compare our model to the conventional SOM model within the CESM and to global observations from the Harmonized World Soil Database, and discuss improvements in estimating global and regional C storage and their response to anthropogenic climate change.

P-1116-08

## Spatial distribution of greenhouse gases measured at the IC3 climatic stations

C. Grossi (1); R. Curcoll (1); A. Águeda (1); O. Batet (1); S. Borrás (1); L. Cañas Ramírez (1); M. Nofuentes Ramos (1); P. Occhipinti (1); E. Vazquez (1); X. Rodó (1); J.A. Morgui (1)

(1) Institut Català de Ciències del Clima, Barcelona, Spain

Changes in the atmospheric greenhouse gases (GHGs) content results as a combination of natural and anthropogenic factors. Understanding the GHGs composition, theiratmosphericvariability and its effect on climate change is necessary for mitigation and adaptation strategies. Indeed, GHGs variability is strongly related to the climaticconditions and closely depend on the latitude.

In the framework of the ClimaDat project funded by Fundació Obra Social «la Caixa», researchers at the Catalan Institute of Climate Sciences (IC3) have established ananetwork of eight climatic stations across Spain performing continuous high-precisionobservations of CH₄, CO₂, N₂O concentrations together with meteorological variables. The climatic stations are located in protected and remote areas within Spanish NaturalParks with middle latitudes ranging between 33N and 41N (Ebre River Delta, Xurés, Valderejo, Gredos, Grazalema, Segura, El Estrecho and El Hierro).

Analysis of the atmospheric variability of GHGs concentration is performed at eachstation of the ClimaDat network. The study of the influence of the atmosphericcirculation on GHGs observations is carried out by a source characterization of the airmasses and their pathways using experimental meteorological data, daily back trajectories and cluster analysis. The observed GHGs concentrations at different latitudes and under different climatic conditions are analyzed and presented in thisstudy.
Multidecadal variability of subsurface
oxygenation off the Central Peruvian Coast
since the nineteenth century

D. Gutierrez Aguilar (1) ; J. Cardich (2) ; C. Almeida, (2) ; R. Salvattecchi, (3) ; D. Romero, (4) ; A. Sifeddine (5)

(1) Instituto del Mar del Perú, IMARPE, Dirección General de Investigaciones en Oceanografía y Cambio Climático, Callao, Peru; (2) Universidad Nacional Federal Fluminense, Niterói, Brazil; (3) Kiel University, Institute of geosciences, Kiel, Germany; (4) Universidad Peruana Cajetano Heredia, Maestra en ciencias del mar, Lima, Peru; (5) Institut de Recherche pour le Développement - IRD, Umr locean (ird/upmc/cnrs/mnhn), Paris, France

Subsurface and benthic biogeochemical conditions over the upper Peruvian continental margin are characterized by oxygen deficiency in the bottom waters, strong fluxes of settling organic matter and reducing conditions in the surface sediments. Previous work has shown a multidecadal cooling trend in the surface waters off Central Peru, and an increase of export productivity, particularly since the 1960's to the present, suggesting an intensification of coastal upwelling. The present study aims to reconstruct the coeval variation of subsurface oxygenation and benthic paleo- redox conditions for the last two centuries, based on laminated sedimentary records of benthic foraminiferal assemblages and redox-sensitive metals (Mo, Re, etc.) in the upper margin off Callao (12°S) and Pisco (14°S). The period between the mid to the late nineteenth century, during which there was an enhanced ENSO activity and paleo-temperatures were higher, was characterized by the occurrence of massive diatom- rich sedimentation events and development of bottom anoxia. Afterwards, decadal variations marked the changes of the proxy records since the late nineteenth century to the mid- twentieth century. Finally for the late twentieth century until the early 2000's, redox-sensitive metal records and benthic foraminiferal assemblages exhibited a trend towards less reducing conditions. This period also featured an increase of organic matter sedimentation and a declining trend of siliceous sedimentation. Our findings suggest that pelagic-benthic fluxes, vertical mixing and/or subsurface ventilation are important factors that modulate the subsurface oxygenation and benthic redox conditions in the Peruvian upwelling system.

Contribution of Carbon, Nitrogen and
Climate Interactions to Terrestrial Carbon
Uptake

A. Jain (1) ; S. Shu (1)

(1) University of Illinois, Urbana-Champaign, Atmospheric Sciences, Urbana, IL, United States of America

There is compelling evidence showing that terrestrial biosphere has acted as a net carbon (C) sink in recent decades. However there is a large uncertainty regarding the magnitude and location of the C sink, predominantly due to large uncertainties associated with C emissions from land use change and our limited understanding of processes affecting plant C sequestration, such as CO2 fertilization effect, impact of changing climate conditions on plant and soil respirations and the interaction of N dynamics with carbon and climate change. This presentation focuses on understanding and assessing the interactions between the C cycle, N cycle and climate and how they might impact terrestrial C sources and sinks in the context of changing global environment (particularly, increasing atmospheric CO2 concentrations ((CO2)), climate change, N deposition and land use change) by using a global terrestrial N-C cycle model in the modeling framework of the Integrated Science Assessment Model (ISM) model to be used here has been calibrated based on site data (Ameripec and LBA field campaign). The model is also evaluated with two sets of global GPP data, MODIS and FLUXNETMTE. Analysis on the results of this study suggests that responses of available N in terrestrial ecosystems to global environmental changes might have not significantly affected the net global amount of terrestrial C uptake over the last three decades, but these N responses have a strong influence on the spatial and temporal distribution of predicted C sequestration as are the influences of global environmental changes.

Are soil organic carbon and its decompos-
sers sensitive to a temperature increase?
New insights from long term bare fallows
and consequences for the terrestrial car-
bon biogeochemical cycle

R. Lefevre (1) ; P. Barré (2) ; PA. Maron (3) ; S. Terrat, (3) ; S. Dequiedt, (3) ; T. Eglin, (4) ; BT. Christensen, (5) ; T. Kätterer, (6) ; S. Houtot, (7) ; OF. Van (8) ; C. Chenu (9)

(1) University Pierre et Marie Curie, Ecosys, Grignon, France;
(2) ENS/CNRS, Dpt geology, Paris, France; (3) INRA, Umr
agroecologie, Dijon, France; (4) ADEME, Direction productions
et energies durables – service agriculture et forêt, Angers,
France; (5) Aarhus university, Department of agroecology –
soil fertility, Tjele, Denmark; (6) Swedish University of
Agricultural Sciences, Department of ecology, Ultima,
Sweden; (7) INRA, Ecosys, Grignon, France; (8) INRA, Ecosys,
Versailles; (9) Agroparistech, Ecosys, Grignon, France

The IPCC projects a temperature increase of 0.3-4.8°C at the global scale by the year 2100 as well as longer and more frequent extreme events such as heat waves (IPCC, 2014). The impact of a temperature increase and of extreme events on the dynamics of stable soil organic carbon (SOC) and its decomposers remains a major source of uncertainty in predicting future changes in atmospheric CO2 levels.

Long-term bare fallow experiments in which plants and organic amendments were excluded for at least 25 years represent a unique research platform to examine this issue as with increasing duration of the treatment, the proportion of stable SOC increases. This study employs soils from four experiments situated at Askov (Denmark), Ultima (Sweden) and Grignon and Versailles (France). We used archived soils sampled at the start of the experiments and after 25, 49, 53 and 79 years of bare fallow, respectively, when the soils had become enriched in stable SOC. The samples were incubated at constant soil moisture and at four different temperatures (4, 12, 20 and 35 °C). The evolution of total CO2 and of 13CO2 from the incubated soils was monitored for more than one year. At the end of the incubation, SOC decomposers were determined thanks to next generation sequencing techniques.

The results indicated a higher temperature sensitivity of SOC in soils enriched in stable carbon. However, we observed no relationship between the duration of the bare-fallow treatment and the temperature sensitivity of SOC. Interestingly, the quality (as determined by 13CO2) of the mineralized SOC depended on the incubation temperature. Our results provided strong evidence for a general relationship between temperature sensitivity and SOC stability upon which significant improvements in predictive models could be based.

This study also showed that soil microbial richness and
equityability were both enhanced in organic resource
depleted soils. We observed a shift from copiotrophic
to oligotrophic microorganisms, indicating a radical
change of ecological niches with carbon depletion
and temperature increase. Surprisingly, the more diverse soil
microbial communities linked to stable soil organic carbon
were more sensitive to a temperature increase than less
diverse communities linked to more labile organic carbon
compounds. It provided evidence that biodiversity is not
the only factor of functional stability and that functional
stability might be a combination of biotic and abiotic soil
characteristics.

Seasonal and inter-annual variability in
wetland methane emissions simulated by
CLM4Me□ and CAM-Chem and compari-
sons to observations of concentrations

L. Meng (1) ; R. Paudel, (2) ; PGM. Hess, (3) ; NM. Mahowald, (3)

(1) Western Michigan University, Kalamazoo, MI, United States of America; (2) Cornell University, Earth and atmospheric sciences, Ithaca, NY, United States of America; (3) Cornell University, Ithaca, NY, United States of America

Understanding the temporal and spatial variation of