and post-monsoon (October–December) seasons. This task is carried out through the analysis of a series of standard indices of precipitation extremes applied to the daily precipitation projections.

The results reveal that West Africa evolves towards increasingly arid and semi-arid regimes with the recession of moist and wet zones, thus adding another element of vulnerability to future anthropogenic climate change applied to the ecosystems and agricultural lands in the regions.

In addition, analysis of the changes in the annual of high intensity precipitation events indicate that the pre-monsoon season experiences the largest changes in daily precipitation statistics. These changes are particularly towards an increased risk of drought associated to a decrease in mean precipitation and frequency of wet days, and increased risk of flood associated with very wet events. Both these features can produce significant stresses on important sectors such as agriculture and water resources at a time of year (e.g. the monsoon onset period) where such stresses can have stronger impacts.

### O-3330a-02

#### Trends in West African floods: A comparative analysis with physiographic indices

NN. Bernadette (1) ; H. Karambiri (2) ; O. Ludovic (3) ; P. Ribstein (4) ; JE. Paturel (5)

(1) International Institute of Water and Environment Engineering, Kadiogo, Ouagadougou, Burkina Faso; (2) 2IE, Ouagadougou, Burkina Faso; (3) UPMC, Metis, Paris, France; (4) Université Pierre et Marie Curie, Laboratoire sylphe, Paris, France; (5) IRD, HydroSciences Montpellier, Abidjan, Ivory Coast

After the drought of the years 1970 In West Africa, the variability of rainfall and land use changes affected mostly flow, and recently, flooding is said to be an increasingly common occurrence throughout the whole of West Africa. These changes aroused many questions about the impact of climate change on the flood regimes in west african countries.

This paper investigates whether floods are becoming more frequent or more severe, and to what extent climate patterns have been responsible of these changes. We analyze the trends in floods of 14 catchments within the main climatic zone of West Africa. The methodology includes two types of sampling flood events, namely the AM (Annual maximum) method and the POT (Peak over threshold), and two perspectives of analysis are presented, precisely long term analysis based on two long time series of flood, and regional perspective involving 14 catchments with shorter length of series.

Mann Kendall trend test and Pettitt break test are used to assess the stationarity of the time series. The trends

detected in flood time series are compared to the trends of rainfall indices in one hand and vegetation indices in the second hand using contingency tables, in order to identify the main driver of change in flood magnitude and Flood frequency. The dependency between flood index and physiographic index is evaluated through a Success Criterion and the CramerV criterion calculated from the contingency tables.

The results point out the existence of trends in flood magnitude and flood frequency time series with two main patterns. sahelian flood show increasing trends, and some sudanian catchments present decreasing trends. for the overall studied catchments, the maximum five consecutive days rainfall index (Rx5d) seems to follow the trend of floods, while NDVI indices do not show significant link between with the trends of floods, meaning that this index has no impact in the behaviour of flood in the region.

### O-3330a-03

#### Evolution of surface temperature and heat waves over West Africa during the near and the far future

M. Camara (1) ; AB. Sarr (2) ; I. Diba (3) ; A. Diedhiou (4)

(1) Laboratoire d'océanographie, des sciences de l'environnement du du, switch, University of Ziguinchor, Ziguinchor, Senegal; (2) Laboratoire d'océanographie, des sciences de l'environnement et du climat (LOSEC), Université assange seck de ziguinchor, Ziguinchor, Senegal; (3) Laboratoire d'océanographie, des sciences de l'environnement et du climat (LOSEC), Université de ziguinchor, Ziguinchor, Senegal; (4) Institute of Research for Development (IRD), LTHE – University Grenoble Alpes, Grenoble Cedex 9, France

The aim of this work is to study the spatio-temporal variability of the future evolution of surface temperature and heat waves over West Africa using regional climate models outputs engaged in COordinated Regional climate Downscaling Experiment (CORDEX) project. CORDEX is an international project implemented by many research centers worldwide which aims to supply reliable climate change scenarios to the scientific community. These simulations are performed with the latest state of the art regional climate models over most emerged lands of the planet for environmental impact studies and also to characterize the associated uncertainties. The data analyzed within the framework of this work are the climate change projections performed with the latest greenhouse gaz emission scenarios: RCP4.5 and RCP8.5.

This work focuses on the near (2020-2050) and the far (2070-2100) future and analyzes the spatio-temporal variability of the surface temperature and heat waves episodes over West Africa; these heat waves remain under studied over this region despite their negative impacts on the populations and their socio-economic activities.

## 3330b - Facing climate change in Sub-Saharan Africa

### ORAL PRESENTATIONS

#### K-3330b-01

#### Assessing climate impacts and adaptation options for cereal systems in West Africa

D. Lobell (1) ; K. Guan (1) ; M. Biasutti (2) ; C. Baron (3) ; S. Benjamin (4)

(1) Stanford University, Department of environmental earth science, Stanford, United States of America; (2) Columbia University, Lamont-doherty earth observatory, New York, United States of America; (3) CIRAD, Montpellier, France; (4) 40 rue Joseph Gaillard, Vincennes, France

Much has been learned in recent years about the nature of climate changes in the West African region, including robust projections of delayed monsoon onset and, in many locations, increased late-season rainfall. This talk will examine the implications of these changes for crop adaptation strategies. Two process-based crop models (APSIM and SARRAH) have used to explore climate change impacts under various management and cultivar scenarios for sorghum, the main crop in the region. Potential

adaptation strategies we test include more conservative sowing rules (to reduce risks of early-season drought stress and crop failure), a switch to longer-season varieties (to avoid shortening of the growth period), increased fertilizer rates and planting density (to take advantage of increased late-season rainfall), switching from photo-sensitive to photo-insensitive varieties, and rainwater harvesting to provide supplemental irrigation. The results are analyzed in terms of effects on both average and variability of yields, with the goal being to identify strategies that will very likely reduce negative impacts of climate trends on average and/or variability of yields, while not sacrificing performance in the current climate. Such strategies could then be promoted as adaptation priorities in the region.

### K-3330b-02

#### The challenge of water resource management in the Lake Victoria basin, East Africa

H. Houghton-Carr (1) ; M. Fry (2)

(1) Centre for Ecology & Hydrology (CEH), Water Resources, Wallingford, United Kingdom; (2) Centre for Ecology & Hydrology (CEH), Water information management, Wallingford, United Kingdom
The Lake Victoria basin, in the headquarters of the Nile in East Africa, is home to over 30M people. As the population continues to increase, demands for water for irrigation, hydropower, and domestic and industrial supply are growing rapidly. The significant drop in Lake Victoria water levels, beginning in 2000 and reaching the lowest recorded level since the 1940s six years later, inconvenienced those who depend on the lake for their livelihoods and generated not just a regional, but a global, debate. A number of factors contributed to the decline of the basin. The Lake Victoria region is characterised by high intra- and inter-annual climatic variability, the consequence of which is significant uncertainty in future rainfall on, and inflows to, the lake. Long good quality hydrometeorological time series records have always been considered important for the assessment and management of water resources. However, many countries in sub-Saharan Africa, and elsewhere, have experienced a marked decline in hydrometeorological data collection and management in recent years.

Lake levels are a primarily a function of regional climate and resultant lake rainfall and evaporation; the impact of water releases for hydropower and other abstractions within the basin is still relatively minor. The Lake Victoria region is characterised by high intra- and inter-annual climatic variability, the consequence of which is significant uncertainty in future rainfall on, and inflows to, the lake. Long good quality hydrometeorological time series records have always been considered important for the assessment and management of water resources. However, many countries in sub-Saharan Africa, and elsewhere, have experienced a marked decline in hydrometeorological data collection and management in recent years.

An increasing need is emerging for long-term datasets to understand how national and basin-scale hydrological regimes are responding to climatic variations and anthropogenic influences. Predicting future water availability, for effective water resource planning under climate change and population growth, requires well- founded predictions of regional climate, hydrology and climate and demands across the basin. Whilst climate and hydrological models can inform about expected impacts of change, validation of these models requires real data. In an interesting paradox that illustrates the current lack of capacity to predict the impacts of climate variability and change on water resources, the East African long rains are observed to be decreasing, whilst climate models predict an increase.

Initiatives to improve understanding of the climate and hydrology of the lake basin are welcomed e.g. GEWEX HyVic regional hydroclimate project, DFID-NERC FCFA (Future Climate for Africa) programme, and WMO data rescue activities which aim to identify and preserve records that capture natural variability.

## K-3330b-03

### Using climate information to build resilience agriculture for farmers in Kaffrine district in senegal

O. Ndiaye (1); M. Seck, (2); D. Ndiaye, (1); R. Zougmore (3)

(1) ANACIM, research and development, dakar, Senegal; (2) SDDR, Agriculture, Kaffrine, Senegal; (3) CCAFS, Bamako, Mali

Senegal, at the image of many Sahelian countries, is one of the most affected area by climate variability. Climate is varying at decadal, inter-annual and sub-seasonal time scales. So population living in such environment are affected by climate shocks in their livelihood.

Funded by the CCAFS initiative there is a 5 years going on project with farmers demonstrating how to use climate information to help farmers in their decision making. This initiative is a pluri-disciplinary and multi-scale processes. In the course of this project many lessons were learnt and many good successful actions that lead to improve farmers decision system.

Downsized climate and weather is produced for the district of Kaffrine. This information is then provided to a few years' old primary working group GTWP which interpret it into actionable decision. In this GTP sit representative of farmer's organization, local decision makers, boundary organization and local department extensions working on agricultural related issues (agriculture, crop protection, forestry, water, seed producers, ...). Then the advices coming out of the GTP is broadcasted through rural radio, bulletin, text messaging as well as during social gathering (naming ceremony, funeral, ...). In this process indigenous knowledge is also used beside state of arts, climate forecasting. During all the crop cycle, each ten days period, information is provided to farmers to help them to

make the best decision. These decisions include choice of the planting dates, avoiding false start, applying fertilizer, removing the herb, harvesting and storage. In this project all initiatives are discussed with farmers representatives and evaluated after the cropping cycle.

A monitoring and evaluation study has shown that farmers in this project was able to cope with climate change better than other farmers, which is in contrast substantially their yields. Today this project in Kaffrine is owned by local government representative who calls and leads such meeting. Now the project is at its upscaling phase to other districts of Senegal using rural radio network. In the upscaling process community radio journalists are trained to understand climate information in order to disseminate such information at broader scale.

We will present lesson learnt and evidence in this project during these 5 years for a climate smart agriculture.

## O-3330b-01

### Yield Gap and the shares of climate and crop management in yield and yield variability of staple crops in West Africa

F. Affholder (1); B. Sultana (2); P. Kouakou (3); C. Poeydeb (4); B. Muller (5)

(1) CIRAD, UR AIDA, Montpellier, France; (2) IRD, Paris, France; (3) CIRAD, Bobo-Dioulasso, Burkina Faso; (4) CIRAD, Martinique, le Laminent, France; (5) CIRAD, BIOS, Montpellier, France

« Yield gap » (Yg) is a key concept of agricultural science for identifying the room for improvement of yields through better management of water resources. In this system, in informed agriculture Yg is the difference between actual yield (Ya) and the theoretical water limited yield (Yw) that would be achieved if solar radiation, temperature and precipitations were the only factor limiting the crop's growth and yield. Changes in Yw over regions and years are due to climate-soil interactions that are not easily modified by crop management, whereas changes in Yg are due to limiting factors that are typically within the scope of crop management such as nutrient availability, weeds, and pests.

We provide an example of yield gap estimates in semi-arid Africa, using yield and other agronomic data collected in farmers' fields of Senegal in 1990 and 1991 and from 2006 to 2012. It illustrates how contrary to what most people would expect climate is not, on average, what most limits yields in that region: yet, actual yields are on average a quarter of what is due to constraints whose reduction is technically possible albeit subject to the economic and environmental relevance of doing so.

Most studies dealing with the impact of climate change on agriculture in West Africa compare Yw under present and future climate as predicted by climate models. The magnitude of those predicted long term changes in Yw by 2050 is down to -20% in the worst scenario combining a +6°C change with a -20% rainfall change. Such changes in water limited yields are certainly concerning, but they are remarkably small compared to the potential +390% increase that would result from closing the current yield gap.

When considering yield variations observed across plots and years, and not anymore regional averages over a few years, what strikes is the stability of observed yields compared to variations of Yw. We used crop model simulations with historical series of 20 years of weather data to compare yield distributions over years of a crop grown using 3 contrasted levels of fertilisation and no incidence of weeds, pests or diseases. For each fertilisation level, the simulated yield reached a maximum value the 'best year' of the series. The three fertilisation levels were chosen so that the maximum simulated yield reached 0.25 Yw, 0.5 Yw, and 0.75 Yw respectively. The resulting simulated yield distributions show that even if management allows increasing the median yield, in many years the climate is the main limiting factor and fertilising has no or a slight impact only. In other words, the way the current climate limits crop production in this region is by making uncertain the output of investing for high yields. Buying fertilizers or working hard for manure collection, transport and distribution do not translate, certain number of years, into more production. For farmers struggling for the daily subsistence of their family,
that kind of risk may not be justified while alternative use of family resources in cash and labour force provide less risky ways to produce subsistence means. Until recently, in many farming systems of West Africa, the growth in food needs due to population growth in rural areas was matched thanks to increases in cultivated or pastured areas rather than increases in crop yields or livestock pressure on land (i.e extension rather than intensification of crop or livestock activities). When rural families reached the limit of this strategy, migrations of many kinds of distance and duration became the adjustment variable to the gap between resources available from farming and population needs. This suggests that for many, it is less risky to leave home than to intensify cropping or livestock systems. Anyway, as job opportunities for migrants from the rural zones are currently low in West African cities and elsewhere, there are legitimate concerns about the way this strategy may soon reach its limit as well.

In terms of climate change, the worst scenario for farmers of that region would be if crop intensification became even more risky under future climate than at present. There is thus an urgent need for joint agronomic and climate research to go beyond the prediction of Yw or of yield under unchanged crop management and determine whether or not the future climate will increase the yield risks associated with crop intensification in that region. But this should not divert from designing and implementing policies incentive to such intensification under present climate, as this might be much easier now than later.

## O-3330b-02

### The re-greening Sahel: How green is green enough ?

C. Dardel (1); L. Kergoit (2); P. Hiernaux (2); M. Grippa (3) ; E. Moulou (2)

(1) LSCE/CESBIO, Toulouse, France; (2) GET, Umr cnrs 5563, Toulouse, France; (3) Université de Toulouse, Get, Toulouse, France

The Sahel region has long been the focus of a debate on its possible desertification, especially because of its sensitivity to climatic variations. This debate was fuelled following the extreme droughts that occurred and peaked in the mid 1970s and mid 1980s. Since the appearance of global and frequent satellite observations, a re-greening theory emerged in the 1990s, in total contradiction with a desertifying Sahel. This re-greening is simply defined as an increase in vegetation index such as the Normalized Difference Vegetation Index (NDVI) widely used by the community as a proxy for aboveground Net Primary Production (ANPP).

The AVHRR instruments onboard the NOAA satellites provide daily NDVI data since 1981 at the global scale, and thus have been widely used for monitoring vegetation production over time. Migrations of large temporal trends over the Sahel since the 1980s clearly evidence the re-greening of the Sahelian belt. However, such data are subject to uncertainties, so that there is a real need for independent validation of this re-greening observed from space. However, this validation is very difficult to make since field measurements of vegetatio mass are scarce at a matching scale, especially in the Sahel, and especially over long time periods.

In the framework of an ILRI-ILCA project and afterwards thanks to the AMMA-CATCH observatory, we benefitted from a long-term database of field measurements collected over the pastoral Gourma region in Mali (1984–2011) and over the agro-pastoral Fakara region in western Niger (1994–2011). These databases provide, among other variables, the aboveground herbaceous mass used at the end of the growing season as a proxy for ANPP. Data available over a large number of sites covering the landscape heterogeneity.

The objective of this study was to evaluate the performance of NDVI products (especially the new GIMMS3g dataset) as compared with long-term field observations. Our analysis over the Gourma region showed that both datasets detected a strong re-greening over the 1984–2011 period, whereas a negative trend was found over the Fakara region in Niger. Moreover, we were able to show contrasted changes depending on the different soil types found in the Gourma: whereas the deep sandy soils show a clear recovery from the droughts, the trend is heterogeneous over the shallow soils with some sites showing a recovery and others not. The picture is also variable over the clayed

soils usually located in small depressions. The negative trend found over the Fakara region could be attributed to changes in land use, since this region has experienced a large increase in agriculture since the 1950s. However, the landscape being fragmented and very dynamic, further studies have to be done to fully understand the changes observed in the vegetation cover.

In both cases, a very good agreement is found between remote sensing data and field observations, giving additional confidence to the satellite archive. The Sahelian re-greening observed over the past three decades therefore seems undisputable. However, this re-greening does not happen everywhere, and contrasted changes may have happened at a finer spatial scale, thus demanding caution in concluding about the resilience of the ecosystems. In any case, since the re-greening is mostly explained by a recovery in rainfall over the past decades, the future climatic conditions and especially the rainfall trend will have a tremendous impact on the evolution of the vegetation cover in the semi-arid Sahel. Of particular concern is the fate of areas already showing an absence of greening (eroded shallow soils, Fakara area for instance).

## O-3330b-03

### The probable impacts of climate change on malaria and Rift Valley fever in Africa

A. Morse (1); C. Caminade (1); A. Jones, (1); J. Leedale, (1) ; A. Tompkins, (2)

(1) University of Liverpool, Geography and Planning, Liverpool, United Kingdom; (2) ICTP, Trieste, Italy

Dynamical models of disease transmission between vectors and hosts and back to vectors have been developed for diseases including malaria and more recently Rift Valley fever. These models are driven by climatic and other environmental variables. This is a complex task, as the models require both accurate projections of the seasonally varying mean values of the climatic drivers and their correct variability across a range of time scales from days to multi-decades.

The relationship between finding parameter settings that represent the correct sensitivities to the climate drivers and the inherent spread of these drivers within an ensemble of climate models: develops the inherent uncertainties in the model outcomes. By using an ensemble of climate models then a signal to noise ratio can be used to display the outcomes of the model projections to decision makers.

Recent FP7 projects QWEci in West and southern Africa and HEALTHY FUTURES in East Africa have run two dynamical malaria models, the Liverpool Malaria Model (LMM) and VECTRI (ICTP) across Africa with a range of bias corrected CMIP5 GCMs. Patterns of changes in malaria distribution in West Africa and East Africa have consistent signals seen into the future using climate model projections. The simulated malaria incidence is increasing over the tropical highlands and the uncertainties related to the disease models are generally larger than that from the climate models. The largest GCM related uncertainty is found at the arid fringes in areas, which have simulated epidemic malaria transmission. Generally the signal to noise ratios in the malaria outcomes improve with increasing projection time and also with higher RCPs.

Recently a new model the Liverpool Rift Valley fever model (LRVF) has been developed using the framework of the LMM but with much more complex structure. It has two dynamic vector models and a dynamic age stratified host model. One main task in its development was parameterising the two different behaviours of the two vectors correctly in the model whilst maintaining the correct sensitivity to the climate drivers.

For both diseases the main uncertainty lies with the future projections of seasonal rainfall patterns and the interannual and intraseasonal variations of this rainfall within the climate models. By using an ensemble of climate models to drive an ensemble of impact disease models, an improved assessment of the model-related uncertainty of the future projections of climate-driven health hazard can be obtained.
## Wind erosion flux and dune front dynamic at the Sahara-Sahel border: case of Kilakina (SE Niger)

A. Abdourhamane Touré (1); AD. Tidjani (2); JL. Rajot (3)
(1) M. Mamadou Daboua (1); B. Marticorena (4); Z. Garba (1)

(1) JEA ADE - Geology, Université abdou moumouni Niamey, Niger; (2) Université abdou Moumouni Faculté d'agronomie, Sols, Niamey, Niger, Republic of; (3) IRD - IEEs-Paris / LISA, lees-paris, Paris, France; (4) Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS-UEP-UDP-IPS, 94010, France

Sahelian sandy soils are more sensitive to wind erosion. In the south-east Niger, the population are essentially rural and their activities are dominated by traditional breeding and agriculture developed on sandhill soils. The region is characterized by a continuous degradation of soil structure by wind erosion. This erosion is emphasized by an important human pressure and recurrent draught wind reactivated dunes. The most productive soils lost more than a quarter of their surface in recent decades because of wind erosion with transformed cultivated area to moving dunes. This work conducted at Kilakina (SE Niger) aimed to characterize wind erosion dynamic of moving dunes. Thus, measurements of wind erosion horizontal flux by using BSNE (Big Spring Number Eight) sand catcher and dunes front dynamics have been done more than 2 years. It's appeared that on moving dune, wind erosion had a temporal and spatial variability. Thus, the foot was eroded particularly between April and Jun while at the top of dune, wind erosion and dune movement can occur all the year. At this place, the intensity of wind erosion reached close to the double of the intensity measured at the dune foot. In another way, the monsoon wind is the most agents of dunes front moving which attained a mean annual displacement near to half-meter.

## Precipitation and disturbance as main determinant of the spatial variability of carbon fluxes in 16 West African ecosystems

EE. Ago (1); EK. Agbossou (1); P. Ozer (2); M. Aubinet (3)
(1) EE. Ago (3)

(1) UNIVERSITY OF ABOMEY-CALAVI, Faculty of agronomic sciences, Abomey-Calavi, Benin; (2) UNIVERSITY OF LIEGE, Department of environmental sciences and management, Liege, Belgium; (3) UNIVERSITY OF LIEGE Gembloux Agro Bio Tech, Department biosystem engineering, Gembloux, Belgium

This study reports carbon fluxes between sixteen different ecosystems and atmosphere in the West Africa region. Data were averaged at annual scale, but obtained by eddy-covariance and other indirect methods. Ecosystem types include forests, savannas, grasslands and croplands under sudano-sahelian and guinean climates. Carbon fluxes data were recorded in the annual mean rainfall ranged between 350 (Agoufou site, Mali) and 1850 mm (Ankasa site, Ghana). The total ecosystem respiration (TER) were found very highly (R2 = 0.71) and Gross primary productivity (GPP) highly (R2 = 0.50) correlated with the annual mean rainfall. Both TER and GPP appeared to be saturated for sites receiving annually a mean of rainfall above 1000 mm.

No clear relationship was found between these two carbon fluxes (GPP and TER) and annual means temperature. Moreover, GPP and TER values ranged from (3.3 and 1850 mm) in the Sahelian fall savannah to (27.0 and 20.5 C ha⁻¹ yr⁻¹) in the sudanian Forest, respectively. Finally, the annual carbon sequestration varied spatially according to the degree of human disturbance and ecosystem management strategy.

## Study of CLOUDSAT products in semi-arid region of Cameroon

A. Lenouo (1)

(1) University of Douala, Physics, Douala, Cameroon

Clouds play a major role in weather and climate processes. In this effect, a variety of satellites was put in orbit in the years 2002 to scrutinize them forming the «A-Train» providing raw data (digital data, images). This work aims to analyze and process these satellite images, preferably those in January and July 2009 in northern Cameroon from satellite data CLOUDSAT in order to explain why in this part of Cameroon, January was a very sunny month against July the raining month. From these data (base image), we applied algorithms (ECMWF-AUX, 2B-GEOPROF, FLXHR...), to extract reflectivity coefficient and masks clouds that cover the region of the different types of clouds which appears and their water rates. We have found that the month of July is marked by a significant presence of clouds at low, middle and vertical development (clouds rushing) against January which is marked by a very light cloud cover at higher floor. Therefore, the results of the profile vertical clouds predict the weather and climate: which equate January to July in the dry seasons and the rainy season respectively. These results can affect an ecosystem and societal functioning, water resources, agro-pastoral and economic activities over the northern Cameroon.

## Impacts of climate variability on crop yield: how do local farmers adapt in Nigeria?

S. Ayanlade (1)

(1) Obafemi Awolowo University, Ile-Ife, Nigeria, Dept. of Geography,, Ile-Ife, Osun, France

The recent impacts of climate variability on crop yield raise the question as to whether there will be enough food in Nigeria in the next century. Various studies on the impacts of climate variability on crop yield have been carried out in different parts of the world and well established through decades of field experiments, statistical analyses of observed yields and monitoring of agricultural production by IPCC and other scholars. The majority of these studies assess inter-annual variability in the climate of West African countries, particularly the magnitude of rainfall variability impact on human activities, including crop production. Surprisingly, little systematic research has focused on the distribution patterns of the impacts of climate variability on crop production, in terms of mapping its spatiotemporal impact using the modern GIS techniques such as Kriging interpolation technique. Thus, the present study uses both Geographical Information techniques (GIS), social and demographic survey to assess the impacts and how local farmers (of different demographic characteristics) adapt to climate variability in Nigeria. The study aimed at using GIS Kriging interpolation technique together with questionnaires methods to examine and map the spatiotemporal impact of rainfall variability on crop yields in the Guinea Savanna Ecological Zone of Nigeria. Both parametric and non-parametric techniques are used for testing whether there have been significant impacts and how farmers adapt to climate change/variability. The result show that modelling with a GIS offers a better mechanism to integrate many scales of data developed for agricultural research. Also the results also show that the zonal variability of rainfall is observed to bring about not only the differences in the types of crops cultivated but also the rate of yield of such crops and deferent adaptation methods. The major finding is that climate change/variability has two major effects on crops. First, during the latter part of the growing season, insufficient soil moisture may restrict transpiration to well below the potential rate, with corresponding reduction in growth and yield. Second, after harvesting the crop, there will be a deep layer of soil which must be recharged to something approaching field capacity early in the following rains before satisfactory growth of the next crop can occur. The results from demographic survey using questionnaires show that local farmers have different adaptation strategies and that the variability climate implies that crop yield is exceedingly variable over space and time.
# Climate and climate variability: case study of the traditional lowland rice cultivation in the middle and upper Casamance Region

M. Bacci (1); M. Pasqui (2)

(1) Institute of Biometeorology, National Research Council, Florence, Italy; (2) Institute of Biometeorology, National research council, Rome, Italy

The Casamance Region is an enclave territory in southern Senegal that has suffered from the sociopolitical instability caused by the separatist movement for the independence of the region in the 1990s and 2000. This has led to a significant delay in infrastructure development to support the economy of the region. Nowadays, it has an unexploited potential due to a series of structural limits for the creation of an efficient supply chain for local agricultural production. The change in the security context of the region and the new Senegal rural development policies provide new opportunities for agricultural production in Casamance.

Among the various food crops, the traditional lowland rice Cultivation by woman in the secondary valleys along the Casamance River is a peculiarity of the region. This crop is mainly grown to cover the food needs of the farmer's family, therefore within a strategy of food security. There are many limits to rice production in the region. The lack of mechanization, the absence of a regular distribution of improved cultivars, poor labor quality and quantity and conflicts with the livestock rearing in the valley make the system very fragile and strongly dependent on seasonal weather patterns. For these reasons, the traditional rice cultivation is becoming marginalized, with a gradual abandonment of the valleys.

In order to preserve lowland rice production and make it sustainable, an analysis of meteorological factors that most influence the crop yield aims to provide useful information for the identification of alternative cultivation strategies and implementation of direct and indirect mitigation practices on crops. The study therefore aims to assess recent climate change recorded in the region with particular attention to the parameters determining a bad or good rain rice crop.

Weather data from rain gauges are quite scarce in the region, often limited only to the registration of the total daily rainfall in the major towns. It was therefore chosen to use the CHIRPS daily rainfall estimate dataset that covers the period from 1981 to 2013 at 0.05° resolution. Attention has focused on assessing the fundamental parameters of the growing season such as total rainfall, number of rainy days, average daily rainfall, onset and the cessation of the growing season. In addition, we evaluated the incidence of dry periods and heavy rains during the germination and flowering period of rice, as these are the most vulnerable stages of the crop. The relationship of these parameters with large scale oceanic and atmospheric forcing was also evaluated.

The variability of these climatic parameters over time are a source of uncertainty for local farmers decision-making process and their ability to adapt to new climatic forcing. Describing the climate, identifying observed trends and overlapping the future predictions derived from atmospheric General Circulation Models has allowed us to define a set of future scenarios that should guide local farmers and policy makers in the orientation of agricultural development policies for the middle and upper Casamance Region.

# Using multi-agent simulation to assess the impact of adaptation scenario on agricultural land use change and household food availability in northern Ghana

B. Badmos (1); G. Villamor (2); S. Agodzo (1); S. Odai (1)

(1) Kwame Nkrumah University of Science and Technology, Kumasi, Ghana; (2) Centre for Development Research, University of Bonn, Bonn, Germany

The impact of climate change and variability on the growth

and development of sub-Saharan Africa (SSA) is severe. Farmers are already changing their agricultural land-use to adapt to the impacts of changing climate. In Ghana, agriculture contributes to food availability and accessibility of some food commodities consumed annually. The capability of agriculture to ensure food availability has been affected by low production, and climate change also plays a significant impact. National policies and strategies to sustain food security at a high level have concentrated on increasing domestic production. Some of the policies aimed at improving farm household resilience to the impacts of climate change may have implication on land-use change. Hence, adequate understanding on the impact of these policies in a temporal manner is vital. This study therefore applied multi-agent simulation (MAS) model to assess the impact of adaptation scenario on agricultural land use change and farm household food availability in northern Ghana. MAS model is able to simulate the impact of human decision processes explicitly. Few studies applied MAS model to relate adaptation with changing climate in West Africa. Application of MAS model for land-use change studies is still at embryonic phase in Africa

We applied the Land Use Dynamic Simulator (LUDAS) as a MAS model to investigate the impact of farm credit as adaptation strategy to climate variability on agricultural land-use change and farm households' food availability in Vea catchment, Upper East Region of Ghana. The model was parameterised using 186 surveyed farm households. From these households, we identified the determinants of their crop choices grouped into household characteristics (e.g., age of head, household size, dependency ratio) and farm plots characteristics (e.g., soil type, wetness index, elevation, upslope area, plot size and proximity features). The crop choice sub-model is directly linked to an agricultural yield sub-model to determine the yields of selected crops. The choice to adapt to climate variability in the study area, household choice of maize adoption with respect to maize cultivation credit (maize credit scenario) was integrated in the decision making and simulated for a 20-year period, and compare with the business-as-usual scenario.

Findings show that under maize credit scenario, maize adopters increased from about 20% to about 50% and the area allocated for maize cultivation significantly increased by about 266% at the expense of traditional crop yields. Average annual aggregated household crop yield was 6.3% higher under the maize credit scenario as compared to business-as-usual scenario. In conclusion, this study shows that access to credit can significantly influence agricultural land-use change and food availability in the study area. However, it may be available as a result of access to farm credit, but sustaining it is big question.

# Comparative study of five statistical methods of climate change analysis in the Niger River basin (West Africa)

D. Badou (1); B. Diekkrüger (2); A. Abel (1); K. Evison (3)

(1) Université d'Abomey-Calavi, Graduate Research Program on Climate Change and Water resources, Abomey-Calavi, Benin; (2) University of Bonn, Geography, Bonn, NRW, Germany; (3) Council for Scientific and Industrial Research, Natural resources and the environment, hydrosciences research group, Pretoria, South Africa

Climate change is characterized by a significant change in the mean values of climate variables. However, the detection of trends in climate variables depends on the methods applied. In this study, 4 commonly used statistical methods, Pettitt's test, Lee and Heghinian's bayesian method, Hubert's segmentation and Mann-Kendall's test at 5% significance level are compared to the cross entropy method. The latter is a stochastic optimization technique initially developed for assessing the number and the position of breakpoints in continuous biological data. From a theoretical point, the approaches of Pettitt as well as Lee and Heghinian provide a breakpoint. The Hubert's segmentation gives multiple breakpoints but within a series even just one extreme value could result as a break. The Mann-Kendall's test detects trend in series for a given level of significance. As for the cross entropy method, it provides multiple breakpoints and offers the possibility for the user to choose the number of breakpoints desired. The five methods were applied to 17 rain gauges of the Beninse part of the Niger River basin whose data cover the periods 1981-2010
(5 gauges) and 1970-2010 (12 gauges). There was 16% of chance of obtaining a trend with the Mann-Kendall's test. The likelihood of detecting a breakpoint with the Pettitt's test, the Hubert's segmentation, the Lee and Heghinian's method and the cross entropy method was 16%, 28%, 72% and 100% respectively. We also noticed that the cross entropy method was 100% and 89% of the times able to replicate a breakpoint detected by the Pettitt and Hubert's approaches and the Lee and Heghinian's method respectively. On the other hand, there was 60% of chance for the Lee and Heghinian's method to reproduce a breakpoint indicated by the cross entropy method. These results suggest that the cross entropy method outperforms the 4 others and should be considered in statistical climate change studies. However, further studies are necessary to confirm the performance of the novel method in comparison to the 4 others.

P-3330-08

## Latitudinal ITCZ sensitivity to the width and depth of the convective activity in WAM

M. Baldi (1) ; G. Dalu (1)

(1) Institute of Biometeorology, National Research Council, Rome, Italy

The onset of the West Africa monsoon (WAM) occurs in 2nd half of June, with a week uncertainty on the date. The onset date is defined by the date of the suddenly migration of the intertropical convergence zone (ITCZ) from the Guinea Gulf to an inland position placed at about 10° North of the equator. Prior to this latitudinal jump the ITCZ stays in an almost stationary position at 5° North for two months; during this period, the convective activity is weak and deepens. This increase of convective activity is observed by satellites as an ORL minimum and as a rainfall maximum over the Guinea Gulf. Towards the end of June, the convective activity weakens over the Guinea Gulf, to crop out few days 5° further inland.

The mechanisms which accompany the development of WAM are rather complex, thus a simple model for the ITCZ behavior is not yet available. One cause reported in the literature of this peculiar behavior of the ITCZ in WAM is the positive feedback between the deepening of Saharan low at the time of the onset and the confining action of the inland orography to the ITCZ inland penetration. Another confining action can exerted by the presence of inland critical lines for propagating easterly wave.

We propose a mechanism which can concur to this sudden latitudinal jump of the ITCZ. Following results found in the literature of a latitudinal ITCZ sensitivity to the shape of the forcing, using a Matsuno-Gill model, we show that a widening of convective activity is accompanied by a temporary weakening of the convergence 5° North, followed by a strengthening of convergence at 10° North, when the width of the convective activity exceeds one equatorial Rossby radius. When this width is exceeded, the ITCZ transition is rather rapid, this is when the convergence maximum settles at at one Rossby radius North of the equator. This mechanism the ITCZ migration is complementary to other mechanisms; the feedback between different mechanisms might be difficult to model in terms of simple theory.

P-3330-09

## Climate change in a tropical region: the case of LAMTO reserve in Côte d'Ivoire

K. Benjamin (1) ; F. Yoroba (1) ; A. Diawara (2) ; Y. Kouadio (1)

(1) University Felix H Houphouët Boigny - Cocody - Abidjan, Physic, Abidjan, Ivory Coast; (2) University Felix H Houphouët Boigny - Cocody Abidjan, Physic, Abidjan, Ivory Coast

LAMTO reserve is located on the center of Côte d'Ivoire in West Africa. Climate variability of LAMTO reserve was studied over the period from 1962 to 2010 (49 years). This study uses climate data (precipitation and temperature) measured on LAMTO geophysical station. In general, rainfall decreased in the reserve. Compared to the average of the 49 years, the region recorded a rainfall deficit over 33 years (1971 to 2000). This deficit was more pronounced during the 90s. On the over side, during the period 2000 to 2010, the rainfall increased.

The region recorded an increase of the mean temperature (+1.4°C) compared to 1960s. This is a sign of global warming. In contrast, from 2001 to 2010, the average minimum temperature decreased (-2.43°C). In fact, this fall causes the decrease of the average mean temperature (-1.25°C) of this decade.

P-3330-10

## Recent rainfall variability and vegetation activity in the experimental site of the Upper Ouémé basin (Benin)

S. Bigot (1) ; T. Do (1) ; B. Dieppois (2)

(1) Laboratoire d'étude des Transferts en Hydrologie et Environnement (LTHE), Université Grenoble Alpes, Grenoble, France; (2) Coventry University, Centre for agroecology, water and resilience, Coventry, United Kingdom

From the late 1990s, the Sudano-Saharan zone is, a priori, wetter than during the two previous decades, which were marked by the development of persistent droughts. This recent evolution is likely to influence local to regional climate and, thus the vegetation cover, the biomass and seasonal phenology in the forest and savannah belt. Contrasted results in simulating the future regional climate trends, however, leaves the future of West African environments open and uncertain. Accurate in-situ monitoring is therefore needed to increase knowledge and understanding of West African regional climatic contrasts and, thus, to exceed diagnostics, which are limited to the semi-continental scales. In this context, an instrumental period was launched in 1997 on the Upper Ouémé meso-scale site (Benin) under the AMMA-CATCH (African Monsoon Multidisciplinary Analysis - Coupling the Tropical Atmosphere and the Hydrological Cycle) observed in the Sahel region. This catchment is located in the western part of the basin of approximately 14 366 km², which is influenced by a Sudanian climate, present different hydroclimatic conditions to those studied in the Sahelian regions. This catchment basin show a lower decrease in streamflow during dry periods, and unclear relationships between land degradation, vegetation cover, surface hydrological and climatic fluctuations. By comparing the satellite images during different time-periods, continuously deforestation and clearing land processes is identified since the 1970s, while anthropized fallow land and savannah are increasing by 24% and 22%, respectively.

This study thus aims to a better regional understanding of the recent rainfall variability and of vegetation phenology through the photosynthetic activity. We compare observed bioclimatic patterns among the four main defined as "non-climatic or climatic degradation" versus "climatic or non-climatic greening" by the current conceptual modeling studies. We focus on the 2001-2013 period using in-situ rain-gauges from AMMA-CATCH, 10-day rainfall estimates from satellite data (RFE: 8 × 8 km), and 5-day photosynthetic activity (NDVI EROS-MODIS: 0.5×0.5 km). Although monthly rainfall amounts are underestined in the RFE data, the interpolated rainfall field from AMMA-CATCH and the RFE dataset are highly correlated (R = 0.93), which ensures a good reproduction of the year-to-year variability.

The recent period (2001-2013), which displays annual rainfall amounts of about 934 to 1302 mm in 2001 and 2003, respectively, is significantly wetter than during the earlier decades (1970s and 1980s) showing regional rainfall amounts rarely above 900 mm. The start of the growing season is significantly correlated with January-May rainfall amounts over the Upper Ouémé catchment and the length of this season is positively correlated with mid-May rainfall amounts. The length of the vegetation activity could therefore be especially sensitive to rainfall at the beginning of the growing phase. Meanwhile, the end of the growing season could be explained by late September to late December rainfall amounts. The end of the growing season is thus delayed by 10 days per decades, e.g., 68th pentad (early December) in 2002 to 70th pentad (late December) in 2010. This could indicate that bioclimatic conditions are more favourable and, thus, lead to a longer duration of photosynthetic activity. This could, however, indicates that green vegetation, which can originate from agricultural land and, thus almost independent from the regional rainfall variability, remain a bit longer in the year. A multivariate statistical analysis of the NDVI thus clearly shows regional contrasts and response specifics over certain areas in different forms of vegetation in the Upper Ouémé Basin. The contrast between protected
native forest (forest reserves) areas and those undergoing a transformation into farmland (crop-growing and fallow land) is very clear. More accurate spatio-temporal analyses (at daily and 250m spatial resolution), such as multi-criteria regional analysis (e.g., dynamic factor analysis), could provide a better understanding of environmental processes involved and the contribution of associated agrosystems.

P-3330-11

HORIZONTAL VISIBILITY as witness of
ENVIRONMENTAL DEGRADATIONS in CEN-
TRAL SAHEL (NIGER) SINCE 1950

B. Hassane (1)

(1) University Abdou Moumouni, Science & Technics Faculty, Niamey, France

Environmental degradation is one of the most important consequences of persistent drought occurring the Sahel between the late1960s and the 1980s. Although central Sahel experiences a partial rainfall recovery since the 1990s, environmental responses to the recent climate trends are still contrasted mainly due to increasing anthropogenic pressure. Analyses of long-term proxy of Sahelian land surface conditions, such as horizontal visibility, and their regional climatic variability, such as regional to local rainfall and wind dynamics, are therefore of major importance in understanding the relationship between climatic and environmental processes.

Time-evolution of the relationship between horizontal visibility (and associated weather types: blowing sand, sandy haze and dust haze) and regional rainfall and wind speed variability have been examined. Over a NE-SW transect from Southern Sahara to central Sahel, 3-times daily measurements (i.e., 6am, 12pm and 6pm) of horizontal visibility and wind, and daily rainfall amounts from 4 weather stations have been selected (Bilma: 18.68N-12.92E; Nguigmi:14.25N-13.12E ; Maine-Soro: 13.23N-11.98E; Niamey: 13.48N-2.17E) and, then, analyzed between 1950 and 2009.

The horizontal visibilities and Sahel rainfall show similar seasonal cycles. Horizontal visibility is increasing during the rainy season (June to September), while horizontal visibility is decreasing during the dry season (October to April). While increasing/suspended dust in the atmosphere, e.g.due to increasing soil erosion and particle transport, is likely to reduce horizontal visibility during the dry, the rainy season actsto reverse this trend by moistening the soil and by blocking dynamically a part of the dust transport. This is thus not true at the southern limit of the Sahara (i.e., in Bilma), where horizontal visibility is lowest between February and August.

At the interannual timescale, decreasing horizontal visibility over the Sahel is linked to increasing occurrence of specific weather types, such as blowingands, sandy haze and dust haze. During the dry season, we note an increase in wind speedsbetween the wet period (1950-1969) and the dry period (1970-2009), which is associated with a decrease in horizontal visibility. The dry period (1970-2009) is also marked by an increase in daily occurrences of weather types associated to low visibilities (sandy haze). However horizontal visibility decreased in Bilma by sandy haze increase particularly since 1967.

One could think that the mechanisms of the climate change are earlier than what is generally admittedonrainfall evolution only. These mechanisms would first affect zones that are most sensitive to wind erosion. In Bilma, it is also observed that the increase of the blowing sand, originating particles in suspension is significant before the drought of 1973., Is it thus also possible that increasing dust in the Sahelian region was caused by the particles mobilized in another source area, which could bembore fragile andancodated northward (e.g., central Sahara)?

Furthermore, it is observed that sandy haze increased in Niameyss the 2000s, even if this region experiences a partial rainfall recovery. That tried to the consequence of a supplement of the environment degradation in relation to the demographic explosion of this area and the overexploitation of the natural environments which was followed from there.

P-3330-12

Weather related income shocks and the
child's health in Burkina Faso

S. Brunelin (1) ; C. Simonet (2) ; C. Araujo-Bonjean (3)

(1) The World Bank, Washington DC, United States of America; (2) ODI, London, United Kingdom; (3) CERDI, Clermont Ferrand, France

We combine health data originating from the 2008 national household survey with meteorological data to test the ability of rural households in Burkina Faso to smooth investment in child health over agricultural income fluctuations. An in-depth econometric analysis of shock transmission mechanisms shows that children are vulnerable to a rainfall shock occurring in the prenatal period or during the first months of life. Results also shed light on the risk-coping strategy set up by households. Households smooth part of positive weather shock but are unable to dampen large negative shocks. Livestock is an effective buffer asset only for a minority of large livestock owners whose children are spared. By contrast, children living in poorly endowed households are severely affected by a weather related income shock. The implementation of weather insurance mechanisms appears to be desirable to fight against moderate malnutrition but would be ineffective reducing severe malnutrition which depends above all on the health and educational status of mothers.

P-3330-13

Rainfall in the Sahel and global tempera-
ture: lessons from a 1500-year long paleo-
climate record

M. Carré (1) ; M. Azzoug (1) ; P. Zaharias, (1) ; A. Camara, (2) ; R. Cheddadi, (1) ; A. Gaye (3) ; S. Janicot (4) ; M. Khodri (5) ; J. Mignot (6) ; N. Mitma (1) ; N. Patris, (7) ; M. Wade, (3)

(1) Institut des Sciences de l'Evolution de Montpellier, Montpellier, France; (2) Institut Fondamental d'Afrique Noire, Dakar, Senegal; (3) Univ. Cheikh Anta Diop, Lpaosf, Dakar, Senegal; (4) IRD, Locean, Paris, France; (5) IPSL, LOCEAN, Paris, France; (6) Institut Pierre Simon Laplace, Locean, Paris, France; (7) Hydrosciences Montpellier, Montpellier, France

As climate model uncertainties remain very large for future Sahel rainfall, it is necessary to look for a long-term perspective in the past climate to better understand the relationship between global warming and the centennial trend of increasing aridity observed in the 20th century in the Sahel. We present here a new record of aridity conditions over the past 1500 years in Senegal, obtained from stable oxygen isotope analyses in archaeological shell middens in the Saloum Delta. Our dataset shows that the actual aridity in western Sahel is unprecedented in the past 1500 years. We observe significantly more humid conditions during the medieval warm period, a transition into the little ice age that was the most humid period in the past 1500 years, and a sharp increase of aridity in the past 200 years. While the recent aridity may be partly due to anthropogenic changes in the local vegetation feedback, a clear link between global temperature and Sahel aridity is revealed in the multi-centennial climate variability. Although this relationship may change in the future with increased greenhouse gases, the climate history supports the scenario of decreasing rainfall in the Sahel in response to future temperature rise.

P-3330-14

Assessing Impact of Climate Change on
Vegetative Species Diversity Using the Nor-
malised Difference Water Index: The Case
of Mutirikwi Sub-catchment, Masvingo
Zimbabwe

L. Chapungu (1)

(1) Great Zimbabwe University, Physics, Geography and Environmental Science, Masvingo, Zimbabwe

Vegetative species diversity is essential for human well-
being because it provides services, such as food, medicines,
clean water and soil stabilization within a catchment or
sub-catchment. However, it is under threat from climate
change which poses a challenge by exacerbating the
impacts of other pressures. Climate change affects
different ecosystems in such ways, depending on the
complexity and original characteristics of the system,
geographical location and presence of factors that may
regulate the extent of the changes. In southern Africa in
general and Zimbabwe in particular, there is still paucity
of scientific understanding of climate change's impact on
vegetative species diversity specifically species richness
and evenness. A plethora of studies has claimed that
climate change affects biodiversity but without focusing
on specific diversity indices. This poses challenges when
designing adaptive and mitigative strategies that are
ecosystem and species specific. This study assesses the
effects of climate change on vegetative species diversity in
Mutiriki sub-catchment using the Normalised Difference
Water Index (NDWI).

To achieve the research objective, the relationship between
vegetative diversity indices (richness and evenness) and
climatic variables (rainfall and temperature) was explored
based on species data directly collected from the field over
a 3 year period and climate data collected from three local
stations (Makoholi, Masvingo airport and Buffalo range).
Relationship between NDWI and species diversity indices
was examined to confirm the utility of remote sensing in
predicting vegetative diversity. NDWI was calculated using
the formula:

$$
\text{NDWI} = (\square\text{NIR} - \square\text{SWIR}) / (\square\text{NIR} + \square\text{SWIR}).
$$

Where ☐NIR and ☐SWIR are the reflectances of the near-
infrared (NIR, 0.78-0.89 m) and shortwave-infrared (SWIR,
1.58-1.75 m) regions, respectively.

The species diversity indices were calculated using the
Shannon Weaver Index which usually combines aspects of
richness and evenness. This index was calculated using the
formula:

H = -Σ (Pi (In (P)) Where the summation is over all species and P1 is the relative abundance of species in the quadrat. This index measures the average degree of uncertainty in predicting to what species chosen at random from a collection of S species and N individuals will belong. Species evenness (E) was calculated using the formula:

E = H/In (S) Where H is the Shannon Weaver index and S is species richness observed within the quadrat.

The resultant predictive model was used to estimate
oxygen in species diversity over a 40 year period (1974-
2014). The species diversity data was then regressed with
climatic data for the same period. These data were also
modeled to project future changes in vegetative diversity
in the face of climate change.

Preliminary findings reflect a significant (P<0.05) correlation between species diversity and climatic variables. The results also indicate that there is a significant (P=0.003, α=0.05) relationship between species richness and NDWI. Species diversity was also significantly correlated (P=0.04, α=0.05) with NDWI. This implies that we can use NDWI to assess changes in species diversity over time. The Mann Kendall test revealed a significant decrease in the rainfall received within the catchment over the 40 year period (1974-2014). The minimum and maximum temperatures over the period were significantly increasing. These changes in climatic variables were associated with a decrease in species richness and evenness. Some species tend to succumb to the environmental changes influenced by climate change resulting in their changes in phenology, abundance and distribution.

The study concludes that climate change in Mutiriki
sub-catchment is influencing species diversity through
changing species phenological features, abundance and
distribution. Besides being a good indicator of water
content in leaves, NDWI has proved to be a useful indicator
of species diversity. The study leads to the understanding
of the relationship between vegetative species diversity
and climate change and this provides a platform for
nations to devise strategies to enhance the resilience of
ecosystems to climatic changes through the adoption of
species based adaptive and mitigative strategies.

P-3330-15

Responding to Climate Change Challenges
In Sub Saharan Africa - A case for Water
Supply

P. Chukwuma (1)

(1) Sustainable Water and Sanitation in Africa, Abakaliki,
Eboni State, Nigeria, Federal Republic of

Change is a permanent phenomenon in all spheres of
life. Many a time changes present both opportunities
and threats on diffent facets. For sustainability, we need
to constantly anticipate changes and their impact. Some
changes come with heavy impact. Climate change is
one of them that has spiral effect on several frontiers of
human existence. It is one phenomenon that deranges
urgent attention. Based on risk assessment, we need to take
proactive steps to either eliminate adverse impacts or
mitigate them or compensate for the perceived impacts.
Sometimes changes present beneficial opportunities. In
dealing with changes, time of reaction and availability
resources are vital.

Sub Saharan Africa Countries are presently existing on
fragile economy. Population is increasing while social
infrastructures are dwindling. This presentation outlines
the challenges of dealing with climate change in Sub
Saharan Africa. It analysis the following issues as it relates
to climate change

Threats of climate change

Opportunities occasioned by climate change

Capacity to respond to climate changes

Effect of climate change

Consequence of climate changes in Sub Saharan Africa

Strategy to coping with climate change challenges

Risk identification

Stakeholders communication strategy

The paper asserts that Sub-Saharan Africa remains the
most vulnerable region in Africa due to inherent poverty
and lack of clear policies on dealing with climate change.
Climate change will have adverse impacts leading to
decreased food production, displacement, increased
poverty, conflicts and reduction in production capacity
in the region. Although, some parts of Sub Saharan Africa
will experience increased agricultural production as a
result of increased rainfall but there exist little capacity to
take maximum advantage of the opportunity or mitigate
the adverse impact of excessive rainfall. Generally, climate
change portends a bleak future for Sub Saharan Africa.
The paper posits that Sub Saharan Africa countries need
to take urgent actions towards tackling the threats of
climate change and plan on take advantage of emerging
opportunities.

The paper elicits that climate change challenges in Sub
Saharan Africa will adversely affect other regions of
the world in one way or the other.

P-3330-16

The impact of global changes on agricul-
ture: the case of Ivorian Basin of Comoé
River

N. Dabissi (1); L. Bruno (2); M. Gil (3); B. Kamagate (1); S. Eric (3); BTA. Goula (1); S. Issiaka (1)

(1) Université Nangui-Abrogoua, Ufr sge, Abidjan, Ivory Coast; (2) 2CIRAD TA 60/02, G-Eau, UMR Cemagref, Montpellier Cedex 05, France, G-eau, umr cemagref, cirad montpellier, MONTPELLIER, France; (3) Université Montpellier 2, Hsm/ird, MONTPELLIER, France

Since some decades, the Ivorian Comoé river Basin faced
environmental and climatic changes. As one of rainfed
agriculture leading forces, climate conditions display (here)
a major role in agriculture transformations. The simulation
of water need requirements, coupled with farming systems,
shows that actual global changes mainly benefit to annual
crops such as corn (Zea mays), and allows the upgrading of
the trees crop as cashew (Anacardium occidentale), rubber
tree (Hevea brasiliensis), etc. However, the precariousness
of the production systems, whose practices have not
deeply changed, has to be linked with the combined
effects of land saturation, agricultural policies and need
of cash faced by farming communities. Therefore, the
diversification and reconversion toward rubber plantation,
are to be considered as farmers' strategies aiming at
finding alternatives for old speculations such as coffee
(Coffea L.) and cocoa (Theobroma cacao L.). For instance, the countryside has been gripped by a frenzy of agricultural development of Chromolaena Odorata and wetlands, which were previously not cultivated. These changes go with intense competition for land that benefits some urban elite who, in example, seeks to cope with retirement by investing in rubber plantation (Hevea brasiliensis). We are witnessing social and spatial reconstructions that, in view of the uncertainty of present conditions, leave small room for innovation. The present survey analyzes the ongoing processes, speculates on their future development, and suggests some ways for sustainable agriculture.

P-3330-17

## Impacts of climate variability and agricultural intensification on the origin of runoff: the case study of the watershed Kolondieba in the south of Mali

A. Dao (1); B. Kamagate (2)

(1) Université Nanki Abrogoua, Laboratoire de Géosciences etEnvironnement, Abidjan, Ivory Coast; (2) Université Nanki Abrogoua, Laboratoire de géosciences et environnement, Abidjan, Ivory Coast

As part of the international research program RIPIECSA (Interdisciplinary and Participatory Research on Interactions between Ecosystems, Climate and Society in Africa), watershed Kolondieba (under Sudanese climate) was selected to understand the mechanism of runoff process in order to improve hydrological model in a context of strong climate variability and agricultural intensification (cotton culture is the main economic activity in the basin). The method used is based on rainfall, hydrometric, geochemical and piezometric data monitoring over the period 2009-2011. The results showed that 2009 and 2010 were normal rainfall years (1300 mm, in average), compared to the average of chronic 1960-1969 ( wet period ), while 2011 has emerged as a dry year compared to the chronic 1970-1992 (dry period). During the last contrasted two years, the runoff coefficient has decreased by half from 2010 to 2011 occasional groundwater discharge deficit estimated at 33%. Monitoring the mineralization of targeted water compartments: rainfall, surface water, and groundwater with the integrator chemical parameter (Electrical Conductivity), showed a very little mineralization of rainfall with an average of 16.99 ± 8.55 μS/cm. Mineralization of surface water is closer to the rainfall's, but it's far from the groundwater's consist of shallow aquifers and deep ones with respectively 120.58 ± 90.07μS/cm-1 and 133.57 ± 85.68 μS/cm-1 in average. This chemical relationship between water compartments showed that deep aquifers don't contribute enough to the runoff. This allowed to deduct a double origin of the runoff on the watershed consists of stormflow and subsurface flow. The separation of the hydrograph in a normal year (2010) gave a contribution of stormflow about 77%. This contribution has increased by 3% in dry year (2011). In these conditions runoff doesn't depend only on rainfall variability, it can be assigned to the land use because cotton culture area is increasing on the basin since 1960.

P-3330-18

## Climate projections in West Africa: evidence and uncertainties?

A. Deme (1); AT. Gaye (2); F. Hourdin (3)

(1) Gaston Berger University of Senegal, Applied Sciences and Technologies, Saint-Louis, Senegal; (2) University Cheikh Anta Diop Dakar, Laboratory of atmospheric and ocean physics, Dakar, Senegal; (3) IPSL-LMD, Paris, France

The Subsaharan Africa response to global warming was uncertain in the models of the third phase of the Coupled Model Intercomparison Project (CMIP3) used for the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), which even disagree on the sign of future rainfall anomalies over this region. This disagreement remains even among models that correctly simulate the twenty-first century as African climate. Our study investigates results from a new ensemble of state-of-the-art climate models which participated of the fifth phase of CMIP (CMIP5) and raises several questions. Do the models agree more on Subsaharan Africa rainfall projections ? Do they well simulate the partial rainfall recovery observed over the last decades ? How well are

models able to reproduce the main features of the West African Monsoon (WAM) ?

Preliminary results of twelve CMIP5 models have shown, in despite of great progress in the representation of MAO characteristics, little change on their climate projections on West Africa compared to CMIP3. Robust tendency to warming over the Sahel, larger by 15 to 50% compared to global warming is noticed. The spread of models projections remains very wide for both temperature and precipitations. But the dispersion in surface air temperature is large over the Sahel and Sahara and seems to be linked to the radiative aerosols properties and surface albedo in this region. Most of CMIP5 models project increasing temperature with 1.8-4.2°C amplitude in a rcp4.5 scenario (3.5-8.5°C in a rcp8.5) in Western Sahel (15W-5W): these values being slightly higher in Eastern Sahel (15W-35W) than in Western Sahel (35W-50W). Temperature changes will have dramatic consequences those associated with precipitation. An opposite response between the western and eastern Sahel for rainfall projections seems to be robust. However, some « outliers models » predict rainfall increase which cancels part of the Sahel warming during the summer monsoon. This finding on the western Sahel gathers more and more models as we advance into the 21st century: as for the period 2011-2040, 60% for the 2041-2070 period and more 80% in the last period. In contrast, the eastern Sahel, although the consensus model is relatively high, it decreases by 80% in the first period to 70% in the last period. The rcp4.5 scenario shows precipitation oscillations around a mean value (positive for the first zone/negative for the second) as well in the East and the West of Sahel, indicating a high interannual variability ; while rcp8.5 scenario gives a tendency net increase of abnormal rainfall in the eastern reaches of the domain (5W-10E), encompassing western Mali, Burkina Faso, northern Nigeria and eastern Niger, where consensus between the models is low on changing rainfall for two scenarios have been characterized.

Finally, our study indicates that further investigations on the rainfall response mechanisms in these outliers models should help to assess their credibility and need to be explored.

P-3330-19

## Why is the « Sahelian paradox » recently exacerbated?

L. Desroix (1); JP. Vandervaere (2); H. Dacosta (3); M. Malam Abdou (4); A. Diongue Niangi (5); A. Bodian, (6); T.ane, (7); V. Tarchiani, (8); P. Vignaroli, (8)

(1) UMR PALOC, Lmi pateo, campus international de recherches ucid/ird de hann, Dakar-Hann, Senegal; (2) LTHE-UJF, Grenoble, France; (3) Université Cheikh Anta Diop, Dept of geography, Dakar, Senegal; (4) Université de Zinder, Dept of geography, Zinder, Niger, Republic of; (5) ANACIM, Dakar, Senegal; (6) Université Gaston Berger, Dept of geography, Saint Louis, Senegal; (7) Université Assane Sekc, Dept of geography, Ziguinchor, Senegal; (8) CNR, Imibet, Firenze, Italy

During the Great Drought that West Africa suffered at the end of the 20th century, hydrological observations highlighted an increase in runoff only in the Sahel, although this was the area where the fall deficit was the highest. From the small experimental plot to the major tributaries basins of the main rivers, runoff coefficients and discharges values increased significantly during the dry period. This was named the « Sahelian Hydrological Paradox ». From the very end of the century, after 1995, rainfall generally increased again in the whole West Africa. Therefore, an increase in runoff after 1995 is easy to explain. However the increase in runoff and discharges values began in 1970, at the very beginning of the Great Drought; the hydrological behavior of Sahelian surfaces remains thus paradoxical at least from 1970 to 1995. Thus its recent exacerbation is not such paradoxical, yet needs to be explained.

The more commonly cited Sahelian paradox explanation is the widespread soil crusting through the Sahel. It is considered as a consequence of the extension of crops, leading to a quasi-disappearance of natural bushes. This trend was accompanied by a decrease in following, the main fertility restoration practice used in the Sahel. After 3-4 years of cropping, a 8-10 years following was traditionally practiced. The population increase and subsequent food needs progressively led to the
abandonment of this practice, and then to e decrease in
crop yields and a general soil degradation (structure, water
holding capacity, fertility, OM content, etc). This was for
long way considered as the main cause of soil crusting.
Soil crusting and its consequence the runoff coefficient
rise was general, within in exorheic areas as well as within
endorheic ones. In the latter, it caused an extension of
ponds, which are the main groundwater recharge sites,
and then it led to a rise in water table levels. The rise in
local runoff due to soil crusting was sufficient to provoke
the change of some northeortic areas into exorheic ones:
the overflowing of some ponds effectively transformed
closed valleys into tributaries of the Niger River. In the sole
Niamey area, 1700 km² of supplementary catchments were
added to the known previous basin; this is close to 50%
of the direct catchment of the Niger River in this region
(small basins directly supplying the Niger River, without
considering the main tributaries). Locally, urbanisation
should also explain an increase in runoff, because it leads
to a decrease in soil permeability (buildings, roads, etc.).
Otherwise gutters are not always maintained and in many
cases they are blocked, their overflowing aggravating then
the flow. Recent flooding of capital cities without rivers
(Ouagadougou in 2009; Dakar in 2012 amongst others)
proved that a purely urban cause of increasing runoff is
possible.

A recent observation of an increase in frequency of extreme rainfall events cannot be considered as a factor of increase in runoff coefficient and flooding. So far, neither the number of rainy events above certain high thresholds of daily amount, nor the amount of rain fallen during these events have (until 2014) exceeded those observed during the 1960s and 1950s decades, before the beginning of the observed increase in runoff coefficients. An intensification of rainfall is observed, however it is evidenced only by the increase in the proportion of rainfall amount observed during high daily rainfall amount events (commonly named extreme events).

The annual flood does not always provoke inundations; however, floods can evolve in inundation owing to at least two series of factors: the silting up of river beds led to the reduction of hydraulic sections, and thus overflow must occur for discharges values which did not cause overflowing in past years. Otherwise, urbanisation again is the cause of severe damages of flooding, because it applies in floodable areas occupied by spontaneous settlements (areas not flooded since the beginning of the Drought, more than 40 years ago), anciently secondary river beds of the main stream flows, or current floodplains.

Soil crusting and then land use changes seem to be the main explaining factors of increase in runoff. Therefore it is important for policy makers to be sensitized about the effects of consequent land use changes on the hydrological regimes of Sahelian rivers.

P-3330-20

Impact of climate changes in the last thirty
years on the second generation of Cocoa
Ivory Coast

A. Diedhiou (1) ; E. Kassin Koffi (2) ; GF. Yao (2) ; LKA. Koko (3) ; AA. Assiri (3) ; B. Boukamé (2) ; A. Konare (4) ; NK. Kouassi (5) ; GR. Yoro (2)

(1) University of Research for Development (IRD), LTHE -

University Grenoble Alpes, Grenoble Cedex 9, France; (2)

National Center of Agronomic Research (CNRA), Central
laboratory of soil, water and plants, Bouake, Ivory Coast;

(3) National Center of Agronomic Research (CNRA), Cocoa program, Divo, Ivory Coast; (4) University Felix Houpouët Boigny, Laboratoire de physique de l'atmosphere et de mecanique des fluides, Abidjan, Ivory Coast; (5)

National Center of Agronomic Research (CNRA), Central laboratory of biotechnology, Abidjan, Ivory Coast

The Ivorian cocoa sector is facing in the recent three
decades with difficulties to plant a new generation of
cocoa due to changes in the annual cumulative rainfall
and the inadequacy of the current crop calendar in
the present climatic context. This study, conducted in the
center-west of Côte d'Ivoire aims to assess climate risks
for cocoa and determine the suitable period to establish
new cocoa farm and to ensure the survival of young trees
during replanting. Agro-climatic data were collected at
the agronomic research stations of Divo and Gagnoa.
Cocoa companies between 1960s and present and the
water needs of cocoa shows that the favorable period of

implementation of cocoa in the current climate context of
the study area is between March and April and not between
May to June as recommended since the 1960s, to enable
young trees to take advantage of the long rainy season
that occurs earlier. A strategy of implementation the
second generation of cocoa taking into account the climate
change observed over the region is proposed.

P-3330-21

Determination of malaria parameters
using meteorological data sets of Senegal
stations and reanalyses products

I. Diouf (1) ; AT. Gaye (1) ; A. Deme (2) ; JA. Ndiome (3) ; B. R. F. (4)

(1) University UCAD, Lab. of atmosphere and oceanic physics, Dakar, Senegal; (2) Gaston Berger University of Senegal, Applied Sciences and Technologies, Saint-Louis, Senegal; (3) University of Senegal, Faculté des fiscas de l'atmosphere, Dakar, Senegal; (4) Universidad Complutense de Madrid, Facultad de fisicas departamento de meteorologia, Madrid, Spain

Climate behavior is an important factor for malaria
development, a vector-borne disease which is a really
public health problem, particularly in Sub-Saharan
part of Africa. High temperatures are favorable for the
quick growth of the mosquitoes and the short life span
of the reproduced cycle of the pathogen known as plasmodium,
while the proliferation of vectors in breeding sites is driven
by precipitations. Due to difficult access of observations
datasets, this study has a huge component of simulations
of malaria parameters using the Liverpool Malaria Model
(LMM) developed by Hoshen et al (2004). The inputs of
the model are meteorological data of stations and different
reanalyses products. The results of this study show that a
two-month lag is often observed between the maximum
of precipitations and the peak of malaria incidence in
Senegal. Malaria occurrence period is centered on the
September-October-November period corresponding
to the end of the rainy season warm and humid. These
findings are highlighted both with stations datasets and
reanalyses.

Otherwise, this study attempts to assess the impact of past, present and future climate features on vector-borne diseases such as malaria. Our findings about malaria changes under climate change will be useful in order to prevent malaria outbreaks due to high probability of climate change.

These results taking account the main climate and
environmental behaviors could be useful in the prevention
of malaria in Senegal and elsewhere.

P-3330-22

Climate variability and its role in accessibi-
lity to and use of water: social and health
issues in informal settlements in Ouaga-
dougou (Burkina Faso)

S. Dos Santos (1) ; FDC. Ouédraogo (2) ; BA. Soura (3)

(1) IRD, LPED (AMU/IRD), Ouagadougou, Burkina Faso; (2)

Université de Ouagadougou, Géographie, Ouagadougou,
Burkina Faso; (3) Université de Ouagadougou, Institut

supérieur des sciences de la population, Ouagadougou,
Burkina Faso

Expected changes to the global environment have led to a
burgeoning literature on climate change vulnerability and
adaptation. A part of this literature focuses on developing
higher-resolution climate models to better characterize
uncertainty in the regional climate projections offered
to decision-makers the "top-down" methods. Another
part of the literature addresses past and present climate
variability and aims to reduce vulnerability by a "bottom-
up" approach. As social scientists, we want to contribute
to this second part of the literature, as we agree with the
geographer Richard Washington and his colleagues
that coping with present climate variability is in itself
enough of a challenge. In this communication, we wanted
to document the diversity and the variability of access to
water depending on the variability of the climate (across
seasons) in an African capital-city characterized by both
population and spatial expansions.

Indeed, better access to water is as much a factor
conducive to development as its result. Improved water
access has many effects on human health. This effect is mediated by both the quality and the quantity of water available in a household. Greater quantities of water and a reduction in the risk of water contamination are two principal means of preventing the diseases transmitted through the faecal-oral route, such as diarrhea, which are a leading cause of death among children in Sub-Saharan Africa. Nevertheless, in terms of water access, sub-Saharan African cities are some of the worst off in the world, with 20% of their populations supplied by an unimproved water source. Urban growth of African cities is leading to the development of informal settlements that do not have access to basic services, including access to water. Changes in both water supply (because of climatic variability) and demand (because of the increase of urban populations and economic growth) have caused many African urban dwellers to experience difficulties in meeting daily water needs. In light of climate change and the continued growth of urban population, there is concern that the gap between the supply and demand for clean water will widen.

We use original data on access to water from a survey implemented in 2012 in the three informal neighborhoods of the Ouagadougou Health and Demographic Surveillance System. The aim was to monitor the diversity and the variability of access and use of water in households, across seasons. Four times per year, a questionnaire was administered to the same representative sample of households (n=1496). It was composed by seven modules addressing issues as varied as the types of water supply, the conditions of collection and storage of water, and the cost of water, as well as various domestic water uses and a health section on water-related diseases for each child under the age of 10 living in the household. To complete the dataset, water samplings was analyzed to test the microbiological quality of the water consumed by these households.

Results show that population's adaptation to seasonal variability is high in terms of diversity and changes in the choice of water sources. This choice implies variability in the distance and in the price paid for water. To a certain extent, in some period of the year, people have not the possibility to choice between different sources: the scarcity lead to pay a high price and/or to travel long distances to a water fountain and, to limit the quantity for each domestic use or to alter the quality of water used. Results also highlight that a number of factors related to water access are associated with higher occurrence of childhood diarrhea, and specifically the use of rainwater. The use of hand pumps is as well interesting owing to its impact on higher childhood diarrhea due to microbiological quality issues.

From these results, we have a broad picture and we can make first hypothesis on the future adaptation to consequences on climate changes in those informal parts of the city, and more generally in African irregular settlements.

## P-3330-23

# Rainy extreme events and phenomenon of flood in the city of Cotonou (Benin): Measure of protection and adaptation of the population

### CG. Etene (1)

(1) Université d'Abomey-Calavi, Géographie, Cotonou, France

More and more, because of the climate change, the populations have to resist frequent and extreme meteorological phenomena, greater climatic variability and changes of the climatic standards. In Benin and more exactly events of city of Cotonou, occurrence of the extreme rain events associated to a lack of adequate politics of the urban development contributed these last two decades to the degradation of the living environments of the urban population.

To appreciate the impacts of the extreme phenomena on the physical and socioeconomic environment of the population, the pluviometric and infrastructural data are used. The statistical analysis was used to determine the extreme rains. The socio-anthropological inquiries will allow to determine the perceptions of the population on their states of vulnerabilities to the phenomenon of floods and to see that they are the strategies of possible

adaptation.

The results of this study show that the populations with average income, the socio-urban equipment's and houses are the most exposed to the phenomena of floods. This vulnerability is often understandable by the collapse of certain houses, the break of ways and bridges under the influence of the phenomenon of the érodibilité provoked by runoff water. Today, it is about development which are capable of adapting itself to the current climatic evolution of the context and future.

## P-3330-24

# Diffusion and scaling of Soil and Water Conservation measures to manage Climate Change in Nigeria

### Ezeji (1)

(1) Rural Africa Water Development Project (RAWDP), Water Resources and Supplies, Owerri, Imo, Nigeria, Federal Republic of

Throughout Nigeria, small holder farmers are increasingly affected by extreme climate and environmental change events. Worsening droughts in particular is ruining the lives and livelihood of many small holder farmers as it continues to hamper farming activities. Their albatross includes water mismanagement, inappropriate land use, as well as poor knowledge of anti-drought measures and this has led to land degradation such as soil erosion and loss of the soil's productive capacity to produce food.

Also the limited potential for dry season farming through soil and water conservation, the non-employment of rain water harvesting technology, as well as conflicts over limited water resources have not helped the situation. Consequently, local livelihoods are being jeopardized while increasing poverty for thousands of these farmers expands.

The paper therefore reviews the adoption and scaling of the World Overview on Conservation Approaches and Technologies (WOCAT) technologies and measures based on the fact that it offers a basket full of Soil and Water Conservation measures that work under specific or under a range of conditions. Soil and Water Conservation (SWC) in this context include the prevention or reduction of soil erosion, compaction and salinity; conservation or drainage of soil water; maintenance or improvement of soil fertility, etc.

The paper also documents, evaluates, compares, monitors and analyses the performance of these WOCAT technologies and approaches such as agronomic, vegetative, and structural and management measures that have proven capable of controlling soil degradation and enhance productivity in the field under existing environmental and climatic variations.

It recognizes and acknowledges the challenge and importance of adapting to climate change. Thus, standardized documentation and evaluation of approved as well as innovative land management technologies and approaches, taking into consideration their adaptation potentials and tolerance towards possible scenarios of climate change, builds the basis to get prepared for the future.

Using the WOCAT methodology, this paper discusses how small holder farmers in eastern Nigeria; whose livelihoods are based on small-scale cropping and livestock agriculture sustainably harvest and use rain water through agronomic, vegetative, and structural measures. It underscores the sheer grit, courage and the determination this vulnerable group and many others bring to the endless challenge of survival. It further underscores that -individuals, households and communities are not passive in the face climate change, and even economic change.

## P-3330-25

# Managing water and nitrogen fertilizers in maize production for smallholder farmers' resilience to climate change impacts

### IR. Fandika (1)

(1) Department of Agricultural Research Services, Kasinthula Research Station, KASINTHULA RESEARCH STATION,
CHIKWAWA, Malawi

Water scarcity is one of the most limiting factor for maize production in Malawi, especially the areas that are vulnerable to climate change. Irrigation alone without proper soil nutrient management fails to enhance maize yield. Participatory embracement of efficient water and nutrient management strategies from on-station to on-farm aims to make it possible to the impacts of climate change. This paper discusses how development and dissemination of efficient water management strategies in maize can adapt smaller farmers to climate change. Irrigation scheduling techniques combined with nitrogen rates and the use of maize varieties efficient in water use were participatory assessed from on-station to on-farm in comparison with farmers' practices. Alternate Furrow irrigation technique was evaluated at on-station in a randomized complete block design experiment with four replicates with three irrigation scheduling treatments: (1) Alternate Furrow Irrigation (AFI); (2) Fixed Furrow Irrigation (FFI) and Convention Furrow Irrigation or farmer practice (CFI). Following on-station successful results, AFI was participatory evaluated at on-farm against, crop stage-based irrigation, daily water budget irrigation scheduling and farmers' practice combined with nitrogen rates using OFD mother-baby approach at five different irrigation schemes. It was RCBD Split-Plot Experiment with above four irrigation scheduling as main treatments. Three nitrogen rates of 100, 125 and 150 kg ha⁻¹ were mini-treatments. Maize was planted at 0.25m apart with one seed per station on a 37.5m² plot. Results for both On-station and On-farm indicated that farmers' irrigation scheduling practice uses more water than the AFI. Alternate furrow irrigation reduced irrigation amount and labour by 38-45% compared to farmer practice. Water use efficiency (WUE) of the AFI (kg ha⁻¹) per crop water use (m3 ha⁻¹) for each irrigation scheduling, differed with irrigation strategy (P<0.0001), location (P<0.05), nitrogen rates and maize varieties. Application of 125kg ha⁻¹ increased yield. Water use efficiency was highest in AFI and lowest in farmer's practice. Both the on-station and On-farm results suggested that AFI strategy and use of maize varieties efficient in water use can definitely adapt farmers to water scarcity by conserving water without affecting economic maize yield.

P-3330-26

## Recurrent climate disasters in Cameroon: an indicator of inadequate adaptation to climate change

RA. Feunta (1); C. Boukar, (2); M. Tsalefac, (3)

(1) Higher Teacher Training College - University of Yaoundé L. Geography, Yaoundé, Cameroon; (2) GIZ/CBLT, Lake Chad Programme, N'Djamena, Chad; (3) Faculty of Arts and Social Sciences, University of Dschang, Geography, Dschang, Cameroon

Cameroon is a central African country with a variety of climates determined by its location on the Atlantic ocean, its extension in latitude from 02° to 13°N, and its varied landscape. As a young country with low-middle income, Cameroon is highly vulnerable to natural hazards, particularly to those related to climate variability and change (World Risk Report, 2014). This results in a variety of climatic disasters which unfortunately recur every years, usually at the same places and during the same periods of the year despite responses from the State and its partners. Therefore, the efficiency of strategies and adaptation approaches in place ought to be questioned. This paper aims at making a comprehensive assessment of the government's approach to adapt to recurring impacts of climate variability and change in Cameroon. At first, we list climate disasters recorded in the archives between 1960 and 2012 in Cameroon while highlighting recurrent events at specific locations and time of the year. Following this historical review, we analyse recurrent disasters for each decade and the rate of change of the occurrence of climate disasters between the first decade of the study period and others. Finally, through content analysis, we review the types of responses implemented by the State to address these impacts and the consideration given to long-term solutions, or planned and anticipated adaptation in the country's key strategic planning documents since independence in 1960. As a result of our work, we have highlighted 450 climate disasters that occurred in Cameroon between 1960 and 2012. They are of various natures: floods, storms, droughts, landslides, hazes, wildfires, disruptions of seasons, sea level rise and

others. All the 58 administrative divisions of the country experienced at least one climate disaster during the above period, which is enough to show that the scale of the problem is national. These unfortunate events occurred each year, with an average of 9 per year and a maximum of 55 in 2010. Similarly, a high increase of these events is noticeable over the years and decades, with a higher occurrence during the 2000s (30% of climate disasters of the period). The number of disasters increases by an average of 28 between two decades. This follows an amplification of climate disasters for the current decade and those to come as projected by some recent publications (Mc Sweeney, C. et al, 2010; Climate Service Center, 2013...). The ten-year rate of change is generally between 161.11% and 616.67%. Thus, compared to the first decade (1960-1969), weather-related disasters are multiplied by at least 2 during other decades and even more during the 2000s (about 6 for all climate disasters and 7 for floods speciality). In some areas (larger cities like Douala and Yaoundé, the Sudano-Saharan plains of the Logone and Benue), recurrent climate disasters were recorded at the same periods of the year with rising intensity and higher damages each time. The government is aware and concern is shown at the highest level. In August 1988 and August 2012, the president of Cameroon, Paul Biya, visited the same places hit by floods in the Sahelian part of the country. Relief type responses like evaluation populations, camouflages in camps, comfort visits, donations in materials and money are the type of measures found in the literature after these disasters. Anticipated and planned adaptation strategies are rare (10% of observations). The government scheme for civil protection is still deficient. More so, an overview of the main strategic planning documents in the medium and long terms indicates low consideration for climate change in the government. Cameroon still lacks a National Adaptation Programme of Action (NAPA) and a National Adaptation Plan (NAP). A process to develop a NAP started in 2012 but is still not finalized because of the weaknesses of the legal and institutional frameworks as well as inappropriate methodology. Meanwhile, disasters and other climate change impacts are increasing and the government is taken unawares most of the time! The recurrence of climate disasters in Cameroon is thus a consequence of poor adaptation to climate change, the strategy in place being more oriented to measures after blows instead of anticipated or planned medium and long term strategies at national level.

P-3330-27

## Trends of Heat Exposure in Northern Ghana

K. Frimpong (1)

(1) Edith Cowan University, Center for Ecosystem management, perth, Australia

Farmers are largely exposed to heat in the performance of their agricultural activities especially in developing countries. As global climate change is intensified, farmers occupational health and productivity need to be safeguarded to ensure food security in the developing world where mechanized farming is at the least minimum. This study present results of yearly trend of heat exposure in northern Ghana where temperature could reach sa high as 45 degrees celcius with WBGT in the of 29 to 37 degrees celcius. Farmers work with minimal rest which can be injurious to their health, the productivity and food security. The study uses Lascar EI USB temperature and humidity sensor which can record temperature and humidity for longer period of time. The results are expressed in terms of heat stress to show the yearly pattern in the north east part of Ghana.

P-3330-28

## Development and Assessment of Non-Li-near and Non-Stationary Seasonal Rainfall Forecast Models for the Sirba Watershed, West Africa

A. Gado Djibo (1); H. Karambiri (2); O. Seidou (3); J.E. Paturel (4)

(1) Institut International d'Ingénierie, de l'Eau et de l'Environnement (2iE), Ecole Doctorale, Ouagadougou, Burkina Faso; (2) ZIE, Ouagadougou, Burkina Faso; (3) University of Ottawa, Civil engineering, Ottawa, Canada; (4) IRD, HydroSciences Montpellier, Abdijan, Ivory Coast
Water Resources Management in the Sahel region, West Africa, is extremely difficult because of high inter-annual rainfall variability. Unexpected floods and droughts often compromise economic activities and sometime lead to severe humanitarian crises. This is exacerbated by endemic poverty, poor preparedness to disaster response, the inadequacy of climate information, and weak institutional capacity. All these factors worsen the vulnerability of sub-Saharan Africa countries to climate changes and make them to be the regions which are highly impacted worldwide. Seasonal rainfall forecasting is one possible way to increase resilience to climate change/variability by providing information in advance about the amount of rainfall expected in each upcoming rainy season. Rainfall forecasting models often arbitrarily assume that rainfall is linked to predictors by a multiple linear regression with parameters that are independent of time and of predictor magnitude. Two probabilistic methods based on change point detection that allow the relationship to change according to time or rainfall magnitude were developed in this paper using Normalized Bayes Factors. Each method uses one of the following predictors: Sea Level Pressure (SLP), Air Temperature (AirTemp) and Relative Humidity (RHUM). Method M1 allows for change in model parameters according to annual rainfall magnitude, while model M2 allows for changes in model parameters with time. M1 and M2 were compared to the classical linear model with constant parameters (M1b, M1c, M2b, M2c, M4b). Results showed that model that allows a change in the predictor-predictand relationship according to rainfall amplitude (M1) and using AirTemp as predictor is the best model for seasonal rainfall forecasting in the study area.

P-3330-29

The competitive impacts of global SST
warming and CO2 increase on Sahelian
rainfall: results from CMIP5 idealized
simulations

M. Gaëtani (1) ; C. Flamant (1) ; F. Hourdin (2) ; S. Bastin (1) ; P. Bracnotton (3) ; S. Bony (2)

(1) IPSL-LATMOS, Paris, France; (2) IPSL-LMD, Paris, France; (3) IPSL-LSE, Gif-sur-Yvette, France

The West African Monsoon (WAM) is affected by large climate variability at different timescales, from interannual to multidecadal, with strong environmental and socio- economic impacts associated to climate-related rainfall variability, which are strongly dependent on the impact of the art-coupled climate models still show poor ability in correctly simulating the WAM historical variability and also a large spread is observed in future climate projections.

In this work, climate simulations from a set of 10 CMIP5 atmospheric global climate models are used to study the July-to-September WAM variability in the period 1979-2008. The individual roles of global SST warming and CO2 concentration increase are investigated through idealized experiments simulating a 4K warmer SST and a 4x CO2 concentration, respectively.

Results show a dry response in Sahel to 4K SST warming, with dryer conditions over western Sahel. On the contrary, wet conditions are observed when CO2 is 4x increased, with the strongest response over central-eastern Sahel. The precipitation changes are associated to coherent modifications in the regional atmospheric circulation: dry (wet) conditions are associated with reduced (increased) convergence in the lower troposphere, a southward (northward) shift of the African Easterly Jet (AE), a weaker (stronger) Tropical Easterly Jet (TEJ). The analysis of the changes in the regional and global connections of WAM dynamical reveals that in the 4K experiment the observed relationships between the global SST and the regional dynamics patterns are weaker, while in the 4xCO2 simulation the connections are more robust. Specifically, a strong coupling between WAM precipitation and Equatorial Pacific and Atlantic SST is observed, along with a reinforcement of the regional connections with the Saharan heat low, the AEJ and the TEJ.

The above results suggest a competitive action of global
SST warming and CO2 increase on the WAM climate
variability, with opposite effects on precipitation. The
global SST warming affects Sahelian precipitation by
weakening the global Tropical convection, while the
CO2 increase results in a strengthening of the regional
dynamics features associated to wet conditions in the
Sahel. It is argued that the large spread in CMIP5 future

rainfall projections may be related to the weight given to
SST warming and direct CO2 effect by individual models.

P-3330-30

AMMA-CATCH a hydrological, meteorolo-
gical and ecological long term observatory
on West Africa

S. Galle (1) ; C. Peugeot (2) ; M. Grippa (3) ; I. Bouzou Moussa (4) ; B. Cappelaere (2) ; J. Demarty (2) ; E. Mougou (5) ; T. Lebel (6)

(1) IRD, LTEHE, 30041 Grenoble Cedex, France; (2) IRD, Hydrosciences montpellier (hsm), Montpellier, France; (3) Université de Toulouse, Get, Toulouse, France; (4) Université Abbdou Moumouni, Niamey, Niger, Republic of; (5) GET, Umr cnrs 5563, Toulouse, France; (6) IRD, LTEHE, 38041 Grenoble Cedex, France

AMMA-CATCH is a multi-scale observation system dedicated to long-term monitoring of the water cycle, the vegetation dynamics and their interaction with climate and water resources in West Africa. In the context of the global change, long-term observations are required to i) gain understanding in eco-hydrological processes over this highly contrasted region, ii) help their representation in Earth System Models, and iii) detect trends and infer their impacts on water resources and living conditions.

It is made of three meso-scale sites (~1'x1') in Mali, Niger and Benin, extending along the West African eco-climatic gradient. Within this regional window (5' by 9'), each of the three sites comprises a multi-scale set-up which helps documenting the components of the hydrologic budget and the evolutions of the surface conditions over a range of time scales: raingages, piezometers, river discharge stations, soil moisture and temperature profiles, turbulent fluxes measurements, LAI/biomass monitoring.

This observation system has been continuously generating coherent datasets for 10 to 25 years depending on the datasets. It is jointly operated by French and African (Mali, Niger and Benin) research institutions. The data-base is available to the community through the website (www. amma-catch.org). AMMA-CATCH participates to several global or regional observation networks, such as FluxNet, CarboAfrica, International Soil Moisture Networks (ISMN) and to calibration/validation campaigns for satellite missions such as SMOS (Europe/France/Spain), MEGHA-TROPIQUES (France/India) or SWAP(NASA). AMMA-CATCH fills a gap over a region, West Africa, where environmental data are largely lacking, and thus, it can usefully contribute to the international networking effort for environmental monitoring and research.

P-3330-31

Preparing for El Nino: a starting point for
climate change adaptation for malaria

A. Gemeda (1)

(1) Ethiopian Public Health Institute (EPHI), Bacterial, Parasitic & Zoonotic Diseases Research, Addis Ababa, Ethiopia

Background on impact of El Nino on malaria in Ethiopia

Malaria outbreaks in East Africa and Ethiopia overlapped
with El Nino events, which has been documented since the
beginning of the 1950s until 2003/2004.

Response of the malaria community based on 2014 early
warning

An El Nino was predicted to develop late in 2014 and was expected to last through at least spring 2015. This translates to a period of heightened likelihood that extreme weather conditions can occur with associated malaria outbreaks in East Africa. The International Research Institute for Climate and Society (IRI) issued a Bulletin "Emerging El Nino conditions: Guidance for the East African Malaria Community following series of consultations.

Difficulties associated with uncertainty of forecast

Forecasting malaria risk remained a series challenge due
to focal nature of malaria transmission in Ethiopia.
Analysis of historical events using Ethiopia ENACTS products

The National Meteorology Agency (NMA) and the IRI have been collaborating on improving climate service since 2008. The most prominent of these activities has been the implementation of the ENACTS (Enhancing National Climate Service) initiative, which was first started in Ethiopia. The IRI and NMA have cooperatively worked to increase the influence of climate variables and malaria morbidity data at district level. In order to accurately assess the influence of climate variables and phenomenon on malaria data, charts and maps from Ethiopian climate series, epidemics at the district levels, and the IRI Data Library, NMA Ethiopian Map Room were used in this analysis. Thus, mean annual rainfall and temperature across Ethiopia displays a normal interannual decadal fluctuation but overall shows a slightly positive trend. The region has been receiving more rainfall and becoming 'wetter', but temperature has been warming and becoming 'hotter'.

An El Nino event in Ethiopia is typically associated with enhanced and increased probabilities of above normal rainfall during the secondary Belg rain season (March-May). However, El Nino rainfall during the primary Kiremt rain season (June-September/October) is more varied and subject to other climatological factors.

To determine whether an El Nino event, subsequent rainfall and temperatures were associated with the below malaria epidemics of the district "hotspots" we assessed these climatic factors in certain three month groups prior to and during the actual epidemic.

Temperatures and relative humidity within the districts were usually already at an acceptable level to encourage malaria transmission. From our prior research, we found that El Nino events in Ethiopia were typically associated with enhanced and increased probabilities of above average rainfall during the secondary Belg rain season. However, this was not substantial in our analysis. Probabilities of a wet El Nino (rainfall) or a hot El Nino (temperatures) deviated from the actual observations. Although the sections in these tools were very insightful in the study of climatic conditions that encourage the probability of malaria transmission, it fails to properly demonstrate the probability of transmission based on ENSO state without a high level of uncertainty. It also does not indicate the strength of the ENSO state, which could be helpful in the future analysis. Monitoring and use of climate information for public health decision requires strong collaboration and sustained coordination between the health sector and climate community. In the last decades, both MOH and NMA have moved towards preparing capacity building and strategic documents. The health sector should benefit better through the recent advancement of climate information services from NMA's ENACTS.

## P-3330-32

### Policies to favour crop intensification and farm income under climatic risk in West Africa

F. Gérard, (1); F. Affholder (2); A. Ricome, (3); C. Poeydebet (4); B. Muller (5); M. Sall, (6); P. Quirain (7)

(1) CIRAD, Nogent sur Marne, France; (2) CIRAD, UR AIDA, Montpellier, France; (3) CIRED, Nogent sur Marne, France;

(4) CIRAD, Martinique, le Lamentin, France; (5) CIRAD, BIOS, Montpellier, France; (6) ISRÀ-BAME, Dakar, Senegal; (7) CNRS, Cired, Nogent sur Marne, France

In West African countries, agricultural production per capita has decreased over the past half century. With continued population growth and the diminishing availability of marginal arable land, pressure on land is rapidly increasing and there is now a common view that crop yield must be increased in this region, especially as this is a wide gap between actual and potential yields. Although there are several factors which may explain this yield gap, the fact that agricultural production takes place in resource-constrained farm households exposed to risk is widely recognized as being important. Indeed, risk discourages the adoption of high-risk, high-return agricultural technologies, which in turn impedes the improvement of yields.

In order to assess how climatic risk constrains intensification strategy in West Africa, we built and calibrated a bioeconomic farm simulation model predicting

the choice to intensify crops or livestock as depending on the availability of key policies in the economic environment of farms, for typical cases in the groundnut basin of Senegal. These cases include two regions contrasted in terms of rainfall (Sine and Saloum) and in each region two typical farms, representing poor and less poor farmers. The model features uncertainty in weather (hence yields) and crop prices, farmer's risk aversion, nine cropping systems representing millet, maize and groundnut with various intensification levels, and the main interactions between crop and livestock: draught animal power, the feeding of animals with suitable crop products (groundnut haulms, cereal straw) and the production of farm manure. Farmers are constraint by land, labour, cash and credit availability. 180 households were surveyed to build the socio-demographic and economic dataset used by the model, and agronomic data were collected from 206 fields.

These key policies analysed are (i) weather index insurances against drought impact on crop yields, either subsidised or not, (ii) subsidies to short term credit for purchasing farm inputs, (iii) subsidies to fertilizer, and (iv) direct payments to farmers. In our simulations, under the current climate and prices of agricultural products and inputs, all these policies appear favourable to the increase of farmers' expected utility for typical farms representing the vast majority of farms in the groundnut basin. Apart for insurance, all of them appear also favourable to intensification of coupled crop and livestock activities for those typical farms. Insurance appears favourable to this intensification strategy only for farms located in the northern part of the region studied, where climatic risk is higher. Among the scenario tested, for most typical farms, combining unsubsidised insurance with subsidised credit appeared as the best use of a given amount of public funds in support of crop intensification. Subsidised insurance allows the farmers to buy costly inputs while insurance reduces the risk that a drought prevents them from reimbursing the credit. Direct payments also rank high in this respect, because they efficiently mitigate the cash constraint. The amount of subsidies required to obtain a given increase of the value of farm production varies across farm types and subtypes in the region, but is relatively reasonable. These results suggest that crop intensification is currently relatively close to a relevant option for farmers and that public policies may favour it by improving the economic environment of farms.

## P-3330-33

### A study of flood intensification in Niamey based on satellite, gauge data and hydrological modeling

M. Gosset (1); C. Casse, (2); C. Peugeot (3); T. Vischel (4); B. Tanimou (5); A. Boone, (6); G. Quantin, (4); V. Pediniot (6); L. Desroix (7)

(1) Institut de Recherche pour le Développement, Geoscience Environnement Toulouse (GET), Toulouse, France; (2) GET, Toulouse, France; (3) IRD, Hydrosciences montpellier (hsm), Montpellier, France; (4) Laboratoire d'étude des Transferts en Hydrologie et Environnement, Saint Martin d'Hères, France; (5) autorité Bassin Niger (ABN), Niamey, Niger, Republic of; (6) CNRS, Toulouse, France; (7) UMR PALOC, LIMI, campus international de recherches ucd/ird de hann, Dakar-Hann, Senegal

One anticipated impact of climate change is a possible intensification of extreme hydrological events, such as floods. Observing the present and past changes in hydro-climatic conditions and the respective roles of climate variability and land use changes, in the increase of floods. In many tropical basins, and notably in sub-saharan Africa there is a deficit of in situ observations. In these regions satellite data and model can help analyzing the hydrological behavior and the recent evolution.

Since the beginning of flows observations, in 1920's, Niamey (Niger) has suffered drastic hydrological changes. Several studies highlighted the hydrograph modification from one to two floods (around 1970's). This hydrological change has been attributed to increased runoff in the basins of the local tributaries (Corouol, Dargol, Sirba), result from land clearing and soil crusting,.. In the last decade (2000's) a dramatic increase in the frequency and intensity of the first flood as been observed. Years 2010, 2112 and 2013 recorded the three highest water levels and peak discharge since the beginning of observations;
and lead to severe material losses and several casualties.

Recent studies have raised the issue of a possible increase in extreme rainfall in the Sahel, which may have an important role in the last extreme floods. This study explores the possible impact of this rainfall change in the Niger flood in Niamey. It focuses on the 125000km² basin between Ansonso and Niamey, corresponding to the drainage area contributing to the first flood. Several long series of satellite and gauge based rainfall estimations, from 1950 to present, are analyzed and used as input to a hydrological model to analyze the possible role of rainfall in the observed evolution of the flood regime and compare with the effect of land use on the basin. These results should provide a basis to anticipate future changes.

P-3330-34

## Towards innovative solutions for monitoring climate changes in observation poor regions: Rain Measurement based on cellular phone networks in Africa

M. Gosset (1); F. Cazenave, (2); F. Zougmere, (3); A. Dounoumia, (3); M. Kacou, (1)

(1) Institut de Recherche pour le Développement, Geoscience Environnement Toulouse (GET), Toulouse, France; (2) Laboratoire d'étude des Transferts en Hydrologie et Environnement, Saint Martin d'Hères, France; (3) LAME / Université Ouagadougou, Ouagadougou, Burkina Faso

The observed anthropogenic global warming over the last century is well documented but the effect on rainfall is less clear, particularly at small scales. Confidence in future precipitation scenarios is currently subject to large uncertainties and can only be assured if there is a comprehensive understanding of the processes controlling rainfall variability, made possible through reliable rainfall records. In many part of the Tropics the ground based gauge networks are sparse, often degrading and accessing this data for process studies, climatological analysis or for validating satellite products is sometimes difficult.

Here a novel approach is presented. It is based on using commercial microwave links from cellular telephone networks to detect and quantify rainfall.

Rainfall monitoring has based on commercial terrestrial microwave links has been tested for the first time in Burkina Faso, in Sahelian West-Africa. In collaboration with one national cellular phone operator, Telefax Faso, the attenuation on a 29 km long microwave link operating at 7 GHz was monitored at 15 t time rate for the monsoon season 2012. The time series of attenuation is transformed into rain rates and compared with rain gauge data. The method is successful in quantifying rainfall: 95% of the rainy days are detected. The correlation with the daily raingauge series is 0.8 and the season bias is 5%. The correlation at the 5 min time step within each event is also high. These results demonstrate the potential interest of exploiting national and regional wireless telecommunication networks for monitoring rainfall in the Tropics, where operational rain gauge networks are degrading and the hydro-meteorological risk increasing.

P-3330-35

## Less rain but more surface water: paradoxical evolution of ponds and runoff in pastoral Sahel

M. Grippa (1); L. Kergoat (2); L. Gal (2); P. Hiernaux (3); J. Ramarohetra (2); C. Dardel (4); E. Mougou (2); C. Peugeot (5)

(1) Université de Toulouse, Get. Toulouse, France; (2) GET, Umr cnrs 5563, Toulouse, France; (3) retired from CNRS GET, Caylus, France; (4) LSCE/CESBIO, Toulouse, France; (5) IRD, Hydrosociologies montpellier (hsm), Montpellier, France

The Sahelian region has experienced a dramatic rainfall deficit over the second half of the last century with severe droughts in the early seventies and eighties which had dramatic consequences on the ecosystems and the population living in these areas. In parallel and paradoxically an increase in surface runoff has been observed over the same period of time in different areas of the Sahel, particularly in Niger where the increase in areas cleared for cropping was suggested as a possible explanation for this phenomenon.

This presentation focuses on the evolution of ponds and surface runoff in pastoral areas in central and northern Sahel, where agricultural activities are very limited. It addresses in particular the Gourma area, in Mali, over which in-situ data on vegetation, meteorological variables and pond water levels are available via the AMMA-CATCH observatory.

The analysis of different satellite data and aerial photographs revealed a spectacular increase in the surface of ponds in the Gourma region over the last 60 years (Gardelle et al. 2010) as well as over other similar zones in Mauritania and Niger. A water balance equation, which includes water volume changes derived by in-situ water level coupled to pond's surfaces, water input by rainfall and water losses by evaporation and infiltration, has been derived for the Agoufou pond. This allowed to quantify changes in the water amount supplying the pond over time, with annual runoff coefficient (estimated as the ratio of water supply over rainfall) going from 0.005 - 0.05 in the 60s-70s, 0.5-1 in the 90s and ranging from 3.5 to 10 in the last ten years.

These results prove that the Sahelian paradox is also taking place non-cultivated areas. Analysis of land cover changes over the Agoufou and Tin Adjar watersheds indicates that vegetation degradation and soil erosion occurring over the shallow soils that generate most of the runoff ending up in ponds, play an important role on the evolution of the hydrological system in these areas.

A first analysis on the capability of general land surface models to represent runoff in this region has been carried out in the framework of the ALMIP2 project (AMMA Land Surface Water Intercomparison exercise, Boone et al. 2009). It was found that the representation of shallow soils has to be taken into better account to correctly represent surface hydrology and runoff in endohoreric Sahel. More generally, better understanding and modeling the eco-hydrological mechanisms operating in this regions and particular the co-evolution of vegetation and runoff systems is necessary to correctly reproduce past changes and predict the future evolution of these ponds.

P-3330-36

## Temperature in the Sahel: mean climate and multidecadal warming in observations and climate simulations CMIP5

F. Guichard (1); J. Barbier (1); C. Leauthaud (2); L. Kergoat (3); D. Bouniol (1); F. Couvreux (1); B. Diallo (4); F. Hourdin (4); S. Janicot (5); R. Roehrig (6)

(1) CNRM-GAME (UMR 3589, CNRS and Meteo-France), Toulouse, France; (2) LSCE, CEA, Gif-sur-Yvette, France; (3) GET (UMR CNRS 5563), Toulouse, France; (4) LMD (IPSL, CNRS, UPMC), Paris, France; (5) LOCEAN (CNRS, IPSL, IRD, UPMC), Paris, France

In a companion study (Leauthaud et al.), we show with observations that the Sahel experienced a strong warming since 1950; it is stronger in Spring, which is already climatologically very hot, and more pronounced in nighttime than daytime temperature. This warming is more pronounced that further South in the tropical Soudanian region and increases with latitude from the Gulf of Guinea to the Sahara. Observations also indicate a decrease of the diurnal temperature range (DTR) which is more pronounced outside of the rainy monsoon season.

In this study, we address the ability of climate models to simulate these salient observed features. We use outputs from the CMIP5 archive, and in particular amip, control and historical simulations. We also use amip-type csfites outputs, that allows a more in depth understanding of the physics underlying the simulation of temperature with high-frequency energy budgets (when available). Here, we evaluate the simulation of the annual and diurnal cycles, of the distribution of temperature, and their multi-decadal fluctuations and changes.

The observations used for evaluation include CRU, GHCN and BEST monthly-mean gridded datasets, but also results from several SYNOP stations located across the Sahel and providing daily minimum and maximum temperature, plus, for some of them, 3-h sampled data. The later are used to compare temperature distributions and distribution shifts in the last decades.

First, it appears that the simulation of the annual cycle of
temperature is very challenging, especially outside of the
monsoon season (cf. also Roehrig et al. J. Climate 2013).
Simulations often display phase shifts of several weeks
to a few months in their extrema (Spring and Autumn
maxima and Summer and Winter minima). Biases typically
reach a few to several degrees in their monthly-mean
values. In numerous models, compensating errors arising
from sub-diurnal to seasonal scales are involved in the
representation of the annual cycle. In general, differences
among models are also found to dominate over differences
among scenarios (amp, historical...).

High-frequency observations of the surface meteorology and radiative budget, available over the last decade, point to thermally physical couplings between radiative fluxes and thermodynamics, for instance between longwave fluxes, DTR, water vapour, clouds and precipitation. Strong couplings are also found in simulations, but they are quantitatively distinct.

The causes and implications of these simulation biases for the study of the Sahelian climate and its future evolution are discussed.

P-3330-37

Characterization of seasons with the wind profiles observed by VHF radar in West Africa

K. Hilaire (1) ; E. Houngninou (1)

(1) University of Abomey-Calavi, Faculty of Science and Technology, Cotonou, Benin

The variability of the West African monsoon had socio-
economic and environmental impacts on populations.
This variability is closely linked to atmospheric circulation,
which also plays a dominant role in the organization of
the monsoon. These experimental results provide information
on the dynamics of winds through the features of the jets.
Data are provided by a VHF wind profiler radar installed
in North-Benin, precisely Nanagatchori (9'6472N, 1'7411E)
during the measurement campaign AMMA program
(2006-2007). This study shows the presence of the African
monsoon jet (AJI) in the middle troposphere (2-4km). It
shows also the presence of the Subtropical Jet (STJ) and
the Tropical Easterly Jet (TE) in the upper troposphere
(10 km). The patterns obtained let distinguish two
great seasons characterizing the Hydrometeorological
Observatory of Oueme Upper Valley. The Hierarchical
Agglomerative Clustering (HAC) applied to the wind mean
velocity and frequency of direction at 10 km associated to
the monthly rain confirms the two great seasons existence:
one dry season (November to March) and wet season (April
to October). The wet season is characterized by three
phases: the pre-wet phase (April, May, June), the heart of
the wet season (July, August, September) and the post-wet
phase (October).

P-3330-38

Description of the agro-climatological
characteristics of the rainy season in sou-
thwestern Burkina Faso for the 1970-2013
period

B. Ibrahim (1) ; W. Fonta (1) ; B. Barry (1) ; S. Sanfo (1) ; K. Greenough (1)

(1) West African Science Service Center on Climate Change and Adapted Land Use (WASCAL), Competence Center, Ouagadougou, Burkina Faso

The rain-fed agricultural system of West Africa is very
vulnerable to climate variability. The different drought
phases during the last four decades (1970-2010) revealed
the weakness of the agriculture system with a high
decrease in crop production, and a significant deficit in
food availability. Many studies have identified the seasonal
pattern of the rain events during the rainy season as a
key driver of agricultural production failure during these
drought phases. In this study, rainy season potentialities
with regard to crop growth (maize, millet, and sorghum)
are described for southwestern Burkina Faso through
seven key climate characteristics: annual rainfall amount,
rainy season onset and offset, dry spell duration, seasonal
maximum rain event, maximum temperature, and wind
speed. These characteristics are calculated from daily
climate data recorded by a local network of 16 stations
from 1970 to 2013. A computation of the intensity of and

occurrence of these characteristics during the rainy seasons
help to draw a description of the drought phases. The rainy
seasons during the drought phases are characterized by a
low annual rainfall amount, a late rainy season onset,
and a more frequent long dry spells (>7days). Unfortunately,
the long dry spells mostly occurred during the most
sensitive crop phases: leaf initiation, flowering and grain
filling. Moreover, the dry spells are accompanied by high
daily temperature. The intensity and the probability of
occurrence of the other extremes events (hot spell and
strong wing) in the rainy season are very high in the study
area mainly during the sowing and the harvest periods.

The adaptation strategies to these worst climate conditions in the region should include a selection of crop varieties with short cycle and the implementation of a supplementary irrigation system and an agricultural insurance scheme.

P-3330-39

Project ACASIS : A early warning system on
Sahelian heat waves and their impacts on
health

S. Janicot (1)

(1) IRD, Paris, France

While the heat wave impacts on public health have been widely addressed in developed countries especially after the intense event over West Europe during summer 2003, no effort has been made to detect them and evaluate their impacts in least developed countries, and especially Africa, where climate is warmer and adaptation capacities are low. Over West Africa preliminary interviews, climate and epidemiologic analyses show however that this problem is emerging. These climate projections indicate that such events should increase in frequency and intensity in the coming decades. However these climate models display important temperature and radiative biases over this region, which must be reduced to provide robust information on the future evolution of heat waves.

Starting from this context, the main objective of ACASIS is to set-up a pre-operational heat wave warning system over West Africa tailored to health risks of the population living in this region. This is a demonstration project focused on Senegal and Burkina where national weather services have already started developing products dedicated to weather/climate and health relationships, and where several health and demographic observatories have been operating for up to several decades. Based on qualified meteorological, climate and demographic data bases, firstly, the dynamics of the heat wave events and their atmospheric patterns will be determined, as well as their evolution over the last decades. Their predictability at short and medium ranges will be evaluated on ensembles of multi-models forecasts outputs. On a longer time scale, control simulations and climate scenarios of the CMIP5/AR5 (5th phase of the Coupled Model Intercomparison Project the results of which are synthesised in the IPCC Assessment Report) database will be analysed and the simulated future evolution and associated uncertainty of these events will be evaluated. More precisely the processes at the origin of model radiative biases will be examined and reduced as much as possible. In parallel, epidemiologic studies associated with interviews will be conducted in the health and demographic sites in Senegal and Burkina in order to evaluate the physiologic and social vulnerability of the African population to high temperature extremes. It will allow to define tailored bio-metropolitan indicators to be used in the warning system. From these outcomes and by implementing downscaling to link the synoptic scale of the heat waves to local bio-metropolitan indicators, we will set-up a demonstration warning system on a "testbed" platform named MISVA, already implemented as the result of a prior collaboration between Meteo-France, OMP and ANACIM, the meteorological agency of Senegal. Based on the interviews, and with the setting of several workshops with stakeholders, public and private institutions, we will be able to provide specific recommendations associated to these warnings. An implementation in the Meteo-France operational system at the end of the project or after might be possible.

To carry on this project, a pluri-disciplinary consortium
has been set-up gathering climatologists, physical
processes specialists meteorologists, biostatisticians,
demographers, socio-economists, epidemiologists,
geographers, and operational meteorological agencies. It
will work through a close collaboration between French and African teams where young African researchers will be highly involved.

## P-3330-40

### Estimation of the West African Monsoon variability through the analyses of the induced wave parameters

P. Kafando (1); F. Chane-Ming (2); M. Petitdidier (3)

(1) University of Ouagadougou, Department of Physics, Ouagadougou, Burkina Faso; (2) Université de la Réunion, Laboratoire de l'atmosphère et des cyclones, Saint-Denis, France; (3) Université Versailles St-Quentin; Sorbonne Université, UPMC Univ. Paris 06, Cnrs/insu, latmos-ipsl, Paris, France

Using local (rainfall) data and global satellite observations (atmospheric fields reanalysis, OLR data, satellite-observed brightness temperature data and cloud cluster data), the activity of convective equatorial waves revealed to be strongly coupled with the West African Monsoon (WAM) variability.

A previous study of wave activity in the West African area (Kafando et al., 2008), revealed that the signature of the monsoon is clearly observed on total energy density in the lower stratosphere (19-23km). The annual cycle and the climatology of wave total energy density showed that peaks of activity match the period of intense convection. In the present study, wave activity in relation with monsoon proxies (convection and precipitations) has been used to analyze the WAM interannual variability using nine years radiosonde observations, Tropical Rainfall Measuring Mission (TRMM) data and Outgoing Longwave Radiation (OLR) data. The several West African meteorological stations located in the latitudinal belt 4°N-20°N.

## P-3330-41

### Impact of climate variability on the water balance of the anthropized Agneya watershed in the southeast of Côte d'Ivoire: application of nTopAmma hydrological model

B. Kamagata (1); N. Dabissi (2); A. Bamba (3); S. Issiaka (4)

(1) Université Nangui-Abrogoua, Laboratoire de géosciences et environnement, Abidjan, Ivory Coast; (2) Université Nangui-Abrogoua Abidjan (Côte d'Ivoire), UFR Sciences et Gestion de l'Environnement (SGE), ABIDJAN, Ivory Coast; (3) Université Nangui-Abrogoua, SGE, Abidjan, Ivory Coast; (4) Université Nangui-Abrogoua, Ufr sge, Abidjan, Ivory Coast

Agneya Watershed (8490 km2) is located in the southeast of Côte d'Ivoire. It is subject to a monsoon (1500 mm annual rainfall) with four contrasted climatic seasons. This basin is also subject to strong human impact that contributes to a change in water balance due to intense agriculture (cocoa, coffee, rubber and food crops).

This work is part of a general framework for understanding the impact of climate variability and agricultural intensification on water resources in the watershed of the Agneya. The main objective of this study is to evaluate by modeling the different terms of the water balance and their evolution over the period 1970-2000. We use a modified version of nTopAmma model developed from observations in the upper-basin of Quémé (wet site AMMA-Catch observatory). The nTopAmma model favours the shallow groundwater efflux as the origin of the flow. The amended taking into account changes in land use and the seasonal cycle of vegetation in the calculation of evapotranspiration can address the impact on the water balance of the plant cover changes.

## P-3330-42

### Climate impact studies in the Sahel: A word of caution

L. Kergoat (1)

(1) GET, Umr cnrs 5563, Toulouse, France

One can easily understand why climate impact studies are increasingly solicited for regions such as Subsaharan

Africa in general and the Sahel in particular. Past climate fluctuations like the multidecadal drought that started in the 70ies had a very strong impact on people, societies, natural resources, and ecosystems. The Sahel drought is the strongest multidecadal drought recorded so far, and this drought combined with a high vulnerability to result in dramatic consequences.

Therefore, it seems meaningful to address the consequences of future climate changes in the Sahel. However, I would argue that a number of limitations and misunderstandings considerably reduce the conclusions one can reach with climate impact studies.

Managers, resources planners, stakeholders, NGOs and scientists in non-climate domain like ecology, hydrology or health, often look for climate projections which have horizons of 20, 30 or 50 years, and in many cases, which are local or regional, from the size of a city to one or a couple of countries. Again, the logic behind these scales is rather straightforward: A couple of decades is seen as the proper timescale for many infrastructures planning (buildings, dams), and for public policies also (laws on resource use and preservation for instance). The spatial scale, from local to regional, obey the same logs. Of course, there are also interests in larger spatial scales (global, continental) and longer time scale (century), but this is not the most common design of climate impact studies.

Based on a review of recent studies, I will argue that caution is needed for impact studies in the Sahel because of two rather simple facts of far-reaching consequences:

- 1) The Sahelian climate at these time-scale is dominated by multidecadal variability. A few climate parameters may escape this statement, like surface temperature just before and after the monsoon season (Guichard et al. this session, Léauthaud et al. this session), and more global parameters like sea level and CO2 atmospheric concentration. However, most parameters related to the monsoon season are dominated by the multidecadal variability: this notably includes rain, temperature during the rain season, and less immediate factors like dust emission in the dry season and ecosystem dynamics that also depend on rain. Of course, these parameters have huge impacts on many systems and activities. I will show examples of effect of climate variability on ecosystems and hydrosystems.

- 2) Present climate models do not have the skills to produce reliable projections of future multidecadal variability. This is true for global, regional and local studies, and even for oceans which multidecadal variability has still to be fully understood. This is a well known issue in the climate community, which is probably not that well recognized in the 'impact' community and by the funding agencies. To make things worse, even the longer term trend is prone to marked differences in climate scenarios for the Sahel.

For these reason, I would call for cautious in impact studies. Multidecadal variability has to be considered, and its understanding is, in my opinion, a prerequisite to most impact studies. Extensive dialog between communities is needed to clarify this issue as much as possible.

## P-3330-43

### Improving the incomes of producers on family farms in the context of climate change in Burkina Faso

P. Kinda (1)

(1) Institut d'Applications et de Vulgarisation en Sciences, Sciences et économie des changements climatiques, Ouagadougou, Burkina Faso

Climate change in the context of Burkina Faso results in recurrent pockets of droughts, heat waves, reduction in the number of rain days and a high variability of rainfall. The consequences of this claimate hazards on family farming are inter-alia, the drop of productions and yields. One of the major challenges of the agricultural sector is improving yields and incomes. Our research aims at presenting the initiatives developed in connection with the improvement of yields and incomes of the producers of family agriculture covering more than 90% of farmers in Burkina Faso. Climate information associated with proven practices and the market information system used could inspire other stakeholders of family farming in similar contexts.
## Impact of climate on groundwater recharge in the crystalline basement rocks aquifer of Northern Ghana

KV. Koffi (1)

(1) WASCAL/ University of Abomey-Calavi, Abomey-Calavi, Benin

Water is the cornerstone of human life and for all economic developments. West Africa and specifically Ghana are no exception to this reality.

Northern Ghana is characterized by a semi-arid climate, with prolonged dry season (7 months of very few rainfall) leading to the drying up of many rivers and streams. In addition, rainfall is highly variable in space and time. Therefore, surface water is unreliable and insufficient to meet the water demands for socio-economic development in this area. As a result, the area is heavily dependent on groundwater for domestic water supply as well as for dry season irrigation of vegetables (cash crops).

However, aquifers in northern Ghana are dominantly the hard rock type (Crystalline basement rock). This aquifer has no primary porosity and may not be able to sustain the increasing demand on the resource. Further, climate change may worsen the situation as recharge is dependent on rainfall in northern Ghana. Therefore, it is important to understand exactly how climate change will impact on recharge to the groundwater for sustainable development and management of the resource.

Previous groundwater studies in Northern Ghana barely analyzed the impact of Climate change on the recharge to the groundwater. This research is aimed at determining the current relationship between groundwater recharge and rainfall and to use the relationships to determine the impacts of changes in climate on the groundwater recharge. The results will inform plans and strategies for sustainably managing groundwater resources in Ghana and the Volta basin.

## From Artisans to Entrepreneurs: Understanding the role of small business for sustainable energy access

W. Kruger (1); R. Aitken (2),

(1) University of Cape Town, Energy Research Centre, Cape Town, South Africa; (2) Restio Energy Pty Ltd, Somerset West, South Africa

The «Developing Energy Enterprises Project» - East Africa» (DEEP EA), which ran from 2008 to 2013, was funded by the European Union (EU) and the Dutch Ministry of Foreign Affairs (DGIs). The Global Village Energy Programme - International (GVEP-I) coordinated the partnership programme responsible for implementing the project. DEEP EA aimed to increase clean energy access among the rural and peri-urban poor in East Africa by assisting entrepreneurs to grow their businesses through enterprise training, mentorship and possible linkages to finance. The project was implemented in Kenya, Tanzania and Uganda, and included three principle technologies and services: improved cook stoves (ICS), briquettes and solar PV (solar lanterns, solar home systems, and PV-based mobile phone charging). During March 2013, Restio Energy conducted an independent terminal evaluation of DEEP EA. This presentation is aimed at capturing and articulating many of the lessons learned - with the purpose of strengthening majority market climate change mitigation enterprises in the future. DEEP EA provides a number of crucial lessons on the nature of support needed to stimulate private sector-led energy access initiatives in Africa. Their project has discovered how to develop people from artisans to entrepreneurs; from someone merely involved in producing a piece of low-tech, low-carbon energy technology to someone who takes ownership of the entire business aspect. Throughout the project, there has been an effective non-technical shift in business performance, which (along with the technical abilities) has raised the performance of a significant number of these DEEP EA supported businesses. Overall, the project has developed a deeper and more textured understanding of the challenges of entrepreneurship in East Africa. The small and micro-business model that emerges presents a blend

between certain defining features of the formal economy and other features with a distinct «informal economy» nature. The outcome is a blend that is more in-tune with the socio-economic realities of not only the entrepreneurs themselves, but the market they service. This is where a great deal of support should be aimed if the private sector is to play its indispensable role in meeting the Sustainable Energy for All targets by 2030.

## Recent climatological trend of the Saharan Heat Low and its impact in West Africa

C. Lavasse (1) ; C. Flamant (2) ; A. Evan (3)

(1) European Commission / Institute for Environment and Sustainability, Climate risk management unit, Ispra, Italy; (2) LATMOS, Paris, France; (3) Scripps Institution of Oceanography, La Jolla, CA, United States of America

The Saharan Heat Low (SHL) plays a crucial role in the West African Monsoon in spring and summer. The recent trend in SHL activity has been analysed using two sets of numerical weather prediction reanalysis. A local increase during the 90's has been found in the two sets of temperature. This increase is stronger within the heat low region than the surrounding areas. This change is accompanied by a modification of the large scale and slow increase of temperature, but we do not observe a change in the filtered signal under 25 days. Despite a large variability of the temporal trends between 15 climate models from the CMIP5 project, the trend is observed using the ensemble mean. Nevertheless, the spatial and temporal evolutions of the HL activities display a large difference between the reanalysis and climate models. The impacts and atmospheric variabilities have been compared in reanalysis and climate models and reveals different behaviours of the climate models to represent the west African monsoon interactions with HL pulsations.

## Changes in temperature and precipitation patterns in Benin Republic between 2000 and 2050

AE. Lawin (1) ; Pl. Akponikpè (2) ; A. Jalloh (3) ; CG. Nelson (4) ; TS. Thomas (4)

(1) Faculté des Sciences et Techniques, Laboratoire d'Hydrologie Appliquée, Cotonou, Benin; (2) Faculté d'Agronomie, Environmental soil physics and hydraulics unit. (pshe), Parkou Kou, Benin; (3) West and Central African Council for Agricultural Research and Development, Dakar, Senegal; (4) International Food Policy Research Institute, Washington, United States of America

Climate change is considered as a worldwide concern. The consequences include changes in temperature and precipitation patterns, with more and more extreme weather events, and shifting seasons. It will disproportionately affect the poor who depend mainly on agriculture for their livelihoods and have a lower capacity to adapt. Benin republic's economy is based essentially on agriculture and its population is projected to at least double (to 18 million) or possibly more than triple (to 25 million) by 2050. Food security is therefore a great challenge for policy makers.

This work focused on analyzing climate changes in temperature and precipitation trends between 2000 and 2050 in Benin. Four downscaled climate models (i.e. CNRM-CM3, ECHAM5, CSIRO-MK3 and MIROC3.2 GCMs) and 2 climate scenarios (A1B and B1) were used to assess changes.

We found that all four GCMs show an increase in the normal annual maximum temperature for the whole country, ranging from slight (1°-1.5°C for MIROC 3.2) to substantial (2.5-3.0°C). The climate models show different outcomes for precipitation levels for the country in 2050. CNRM-CM3 and ECHAM 5 showed increased precipitation, while the two other models (CSIRO Mark 3 and MIROC 3.2) showed areas of precipitation decrease, mainly in the south. These changes in climate may affect in varying ways crop production and food security.
## Observed multidecadal changes in air temperature from 1950 to 2010 in the Sahel

C. Leauthaud (1); F. Guichard (2); L. Kergoat (3); J. Barbier (2)

(1) LSCE, CEA, Gif-sur-Yvette, France; (2) CNRM-GAME (UMR 3589, CNRS and Meteo-France), Toulouse, France; (3) GET, Umr cnrs 5563, Toulouse, France

The Sahel experienced in the last decades the strongest climatic signal ever recorded. Alongside the well documented changes in precipitation amount and frequency of extreme events, modifications of air temperature stronger than the global increase in mean annual temperature in the past 60 years is evidenced. However, little is known about the changes in the seasonal and diurnal cycles in temperature and the underlying processes. Furthermore, most studies addressing this subject rely on satellite products or gridded datasets and not directly on observational data, thus limiting their temporal depth and accuracy.

The objective of this study was to address this shortcoming by analyzing observational air temperature data obtained from the global climate database GIST for the Sahel region (roughly defined here by the box 11°N–17°N ‘18°–20°E’) and its surroundings during the period 1950–2010. To do so, all available synoptic and daily temperature data were collected. Only stations retaining less than 20 % missing data were retained for analysis. This final database was constituted of over several tens of stations spread over the Sahel region. Analysis focused more specifically on (i) characterizing the seasonal and daily cycles of daily minimum and maximum temperatures, and (ii) comparing them with available gridded datasets for specific localities.

Preliminary results show that temperature characteristics have indeed evolved, with an increase of mean daily air temperature of over 1°C over all the Sahel. Increases are most important at the onset of the rainy season. The observed decrease in diurnal temperature ranges is mostly explained by strong increases in minimum air temperature. Finally, the evolution of temperature characteristics differed geographically, with stronger variations in the northern part of the Sahel. It is now important to compare these observational data with meteorological reanalysis and with historical simulations of Global Climate Models. This is undertaken in a companion presentation by Guichard et al.. These modifications of daily temperature, diurnal temperature range and minimum and maximum air temperature can have serious consequences on agriculture, but also human health, even the more as increases have occurred in periods of the year during which temperatures are already critically high.

## Innovating low carbon waste management models in developing countries: a case of local community based artisanal entrepreneurship in Sub Saharan Africa countries

J. Li (1); L. Dayan, (2)

(1) Curtin University of Technology, Perth, Australia; (2) University of Paris 1 Panthéon-Sorbonne, APREIS, Paris, France

The prospect of global economic growth in the next decades will depend on the performance of emerging and developing economies given their rapid population growth and accelerated urbanisation and industrialisation. Growth in emerging markets will not sustain without the increasing studies on the economic viability of their economies and the global environmental challenges such as climate change. The global sustainability targets can only be achieved when actions are taken at both global and local levels. It entails decoupling the global economy of pollution, shaping autonomous and endogenous local development, organizing productive social inclusion while enabling decentralized governance of a multipolar global economy at the local level, driven by local solidarity initiatives and culture-specific entrepreneurship in developing nations. This paper aims to shed light on how local entrepreneurship innovations may contribute to sustainable and inclusive growth, enhanced human capital and global equity in sub-Saharan Africa from the perspective of a specific sector—namely waste, in which

multidimensional challenges of waste reduction, cultural diversity conservation, community solidarity and climate change governance are intertwined. One key element of sustainable development and climate governance in SSA is the waste. Today waste is a thorny issue in many SSA countries and has resulted in significant resources loss, income deficiency and poverty concentration, greenhouse gases emissions, and disastrous environmental impacts including public health degradation. The widespread practice of dumping waste into water bodies and scattered dumps prompted by fast-growing urbanization contribute to aggravate the problem. In effect, investments from FDI and aid programmes led by international institutions such as UNEP, World Bank, European Commission have indeed brought capitals and technologies necessary for the socioeconomic development programmes in SSA countries. It is not yet clear how these parachuted aids and investments are accommodated locally and how they impact traditional artisans in waste treatment from the perspective of poverty reduction and local governance for climate change mitigation and adaptation. It would be inappropriate to transplant directly the top-down waste management model developed in industrialized countries to SSA without adaptation to local community-based solidarity culture and inclusion of bottom-up entrepreneurship innovations, particularly in the domain of utilisation of agricultural residues for generating renewable energy. This study attempts to answer a key climate policy question: how can low-income SSA countries develop a climate friendly waste-based circular economic growth model incorporating bottom-up entrepreneurship innovations? The model takes into account traditional artisanal know-how and communal solidarity as well as sustainability ethics within an intercultural environment, which is pertaining to Africa in the context of growing urbanization and an economic transition. Our main objective is to develop a low-income community-based waste management model in SSA, namely Cameroon, Ivory Coast, Burkina Faso, Guinea, Senegal, Niger and Ghana. To render our research results replicable to a broader development perspective, we draw lessons from the experiences in the projects implemented by APREIS in Burkina Faso and Cameroon over the past years, and also from some Latin American countries such as Brazil and Argentina in particular where waste management is characterised by bottom-up civil organisation model with limited state intervention. Community economy experiences learnt from our fieldwork suggest that development policy encouraging ‘inclusive innovations in climate friendly waste management entrepreneurship’ has to incorporate four building blocks: economic, social, environmental and cultural dimensions within a coherent climate governance framework in SSA countries.

## Multi-Agent System for simulating the change pattern of agricultural land-use under changing climate in the semi-arid region of Ghana

A. M. Laouali (1); G. Villamor (2); MA. Emmanuel (3); KB. Nicholas (4)

(1) Kwame Nkrumah University of Science and Technology (KNUST), Civil Engineering, Kumasi, Ghana; (2) Centre for Development Research, Bonn, Germany; (3) University of Ghana, Legon, Department of geography and resource, Accra, Ghana; (4) Kwame Nkrumah University of Science and Technology (KNUST), Agricultural engineering, Kumasi, Ghana

One of the operationalised tools of human-environment system (HES) approach is Multi-Agent System (MAS) which has been used in a number of areas to study the dynamics and management of human and natural systems especially when facing unexpected disturbance. Therefore, increasing studies are interested in using MAS approach for the understanding of agricultural adaptation to environmental change. However, when it comes to the use of MAS for the operationalization of adaptation decision making in agricultural land-use based on the implications of climate variability, only very few studies empirically operationalise the concept in their simulations. In this research, Land Use Dynamic Simulator (SKY-LUDAS as referred to the communities where it was implemented: Sirigu-Sumbrungu-Kandiga-Yuwa) framework was applied by integrating the two step-decision making sub-models. Therefore, three scenarios have been designed and tested: baseline (Baseline), perception of climate change (PCC) and No perception of climate change (NO-PCC). Simulation results of SKY-LUDAS suggested that the
land-use behaviour in the study area reflects a tendency of subsistence farming. In terms of farm-households' livelihood strategy, especially the structure of the farm income, there was a growing contribution of rice and groundnuts. Accordingly, SKY-LUDAS has received a gradual shift among land-use types from traditional cereals farming to the cultivation of groundnuts and rice. As a result, this study has a merit of contributing to answer the critical question on whether certain adaptation decisions are stimulated by climate change. Therefore, farmers in the study area have adapted their land-use to climate change based on their income source and gradual change in the cultivated land-use in the purpose of being less dependent on the vulnerable farming systems.

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A Bayesian Trend analysis of annual maximum stream flows of the Oti River Basin (West Africa)

B. H. Maleki (1)

(1) WASCAL GRP - Climate Change and Water Resources, University of Abomey-Calavi, Benin, Benin

Non-stationary analysis of hydrological extremes is crucial for characterizing hydrologic phenomena, planning and management of hydraulic and water resources systems. Moreover, Bayesian analysis appears to be a consistent framework for deriving complex statistical models and implementing uncertainties into induction problems. For this study which is conducted in the Oti River Basin, West Africa (75,859 km²), a set of discharge data from two gauging stations in Benin (upstream at Porga) and Ghana (downstream at Sabowa) were obtained from the national hydrological services. These records were quality checked and processed in order to derive long term annual maximum stream flows (AMSF) time series between 1952 and 2008. The Generalized Extreme Value (GEV) distribution was fitted to AMSF under stationary and non-stationary conditions. The non-stationary condition tested here is the variation of AMSF over time. To this end a time covariate was introduced in the location parameter of GEV distribution using a Bayesian approach. The results showed better non-stationary fitting for the upstream site (Porga) which exhibits significant decreasing trend in AMSF. The reservoir between the two gauging stations strongly controls the flows at the downstream gauging station which in turn affected the detection of no significant trend in AMSF while annual maximum rainfall is changing over the basin. The estimated return levels under non-stationary conditions showed a decreasing trend over time. This study provides good baseline information for climate change and flood frequency research within the basin. It is also important to understand the impact of the reservoir on the downstream discharge in general, but also on extremes and the occurrence of floods.

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Impact of deforestation on surface water and energy feedbacks in sudanian region of West Africa

O. Mamadou (1); S. Galle (2); JM. Cohard (3); C. Peugeot (4); J. Seghieri (5); B. Kounouhewa (6); O. Mamadou (7)

(1) Université d'Abomey-Calavi, Laboratoire de physique du rayonnement, Abomey-Calavi, Benin; (2) IRD, LTHE, 30041 Grenoble Cedex, France; (3) Université Grenoble Alpes, Lthe, Grenoble, France; (4) IRD, Hydrosciences montpellier (hsm), Montpellier, France; (5) I.R.D., DGSD-Département Environnement et Ressources, Montpellier cedex 5, France; (6) Université d'Abomey-Calavi, Laboratoire de physique du rayonnement, Abomey-Calavi, Benin; (7) Université de Liège Gembloux Agro-Bio-Tech, Exchanges ecosystems - atmosphere, Gembloux, Belgium

In West Africa, surface atmosphere exchanges have been found to impact both regional and local features of the Monson. At local scale the spatial patterns of evaporative fraction can drive the trajectories of mesoscale convective systems. Within Sudanian climate, ~80% of the precipitation returns to atmosphere through evapotranspiration. However, this amount and its seasonal dynamic may vary with the vegetation cover. Consequently, one might expect that any land use or climate changes could lead to the modification of the surface water and energy feedbacks, and, thus both the atmospheric and the regional water

cycle. Finally, the sudanian region of West Africa is submitted to a 3% demographical increase per year, which induces a drastic expansion of crops areas. This study aims at quantifying the changes in evapotranspiration and sensible heat flux regimes caused by a such land use change under sudanian climate.

The AMMA-CATCH observatory documents evapotranspiration flux in the Sahel since 2007. A multi-annual energy budget term of the clear forest and a cropland area are analysed. It is shown that sudanian forest evapo-transpirated always more than crop areas because of agricultural practice, which cleaned to bare the crops areas with bush fires and water availability for trees. Thus, during the dry season, the cultivated areas remain bare. At the same time, more than 1 mm per day of evapotranspiration rate is measured above the forest area despite the lack of precipitations. Deep rooting systems allow the clear forest to get access to water from deep soil layers for transpiration throughout the dry season. During the rainy season, low but significant differences in evaporative fraction are also observed. These differences will lead to a large deficit of the water vapour that returns to the atmosphere, and, thus, will change significantly the continental water cycle when forests will be replaced by crops. In the future, agroforestry that combines local crops ( Yam, manioc, millet, etc.) and sparse trees could mitigate surface feedbacks. Finally, the selected trees could provide extra agricultural products taking benefit from deep water availability, but also strengthen social equilibrium between men and women.

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Impact of Climate, Agriculture and Vegetation in the Sahel in the recent past : the CAVIARS Projet

B. Marticorena (1); CT. The (2)

(1) LISA, CNRS-UEP-UPD-IPSL, Crétail, France; (2) GET; CIRAD; CNRM-GAME; IESS-Paris; LTHE ; JEAI ADE, Toulouse, Montpellier, Bondy, Grenoble, Niamey, France

The semi-ard regions of the Earth are particularly vulnerable to wind erosion. The Sahelian region experienced contrasted climatic conditions during the last decades, with severe drought in the 70's and 80's and a relative re-greening in the recent years. Over the same period, changes in land use have occurred with an increase of the cultivated surfaces leading to a decrease of fallows and rangelands. As a result, a significant proportion of the land is bare or sparsely vegetated, and thus is not efficiently protected from the evasive action of wind. In this region, wind erosion tends to decrease the productive capacity of the soils whose fertility is already very low. In addition, the impact of wind erosion is expected to increase significantly in the near future (1) in relation with the expected changes in climate (in particular the modifications of precipitation and surface wind) and (2) in response to the increasing land use due to population increase and the related food needs.

The aims of the CAVIARS project (Climate, Agriculture and Vegetation: Impacts on Aeolian ERosion in the Sahel) are to develop an integrated modeling tool to describe the evolution of wind erosion in the Sahel in connection with climatic and land use changes, to validate this tool in the current period by making the best possible use of the numerous data sets acquired in recent years over West Africa, and to test its ability to reproduce specific events (such as the drought in the Sahel) of the recent past (about the last 5.0 years). This project is based on a modeling approach of this recent past (hindcasts) that is justified by the need to ensure the robustness of the simulations with different forcings prior to any simulation of future scenarios.

The proposed strategy is (1) to develop or optimize reliable modeling tools for quantifying the various terms (downward and upward) and for considering for changes in the intensity of wind erosion (2) to synthesize quality- checked observations, that can be used as direct or indirect indicators of wind erosion (precipitation time series, changes in vegetation cover, atmospheric dust load,...) (3) to implement a validation strategy based on the quantification of wind erosion both locally, measured on grazed and cultivated plots, and at the regional and continental scales.
# Using longterm rainfall and streamflow trends to inform local level agricultural water management in Benin

M. Masiyandima (1) ; C. Mufwaya, (1)

(1) AfricaRice, Sustainable productivity enhancement, Cotouon, Benin

Due to lack of irrigation and water storage facilities rice production is mostly practiced under rainfed conditions across most of Benin. Farmers use temporary water control structures to divert water from streams to rice fields in valley bottoms. This type of production system is dependent on rainfall and streamflow. It is vulnerable to natural variability of rainfall and streamflow. Analysis of rainfall and streamflow observed in the Ouémé River basin between 1951 and 2012 was carried out to understand rainfall and streamflow trends at local level to identify relevant climate indicators and data that best serve the needs of farmers for water management at local level as a way to improve water management and productivity under a changing climate. The Mann-Kendall test was used for the analysis. Significant rainfall trend was confirmed at 3 of the 19 rainfall stations in the basin. The 3 stations showed increasing rainfall at 95% confidence level. An increasing trend was evident at 13 stations but not significant at 95% confidence level while a decreasing trend was evident at 3 stations. Increasing streamflow trend (95% confidence) was confirmed at 3 of the 13 streamflow gauging stations in the basin. Further analysis of streamflow for the non- perennial rivers in the basin showed increasing number of days with zero flow at 2 of 8 streamflow gauging stations and decreasing number of days with zero flow at 1 station (95% confidence). Long term trend of monthly rainfall for June, July, August and September (the rice growing season) provided additional insight into variability at local level. The research highlights the relevance of considering indicators that may be relevant for local level water management in support of rainfed agricultural production in the Ouémé River basin in Benin.

# Assessment of climate change impact on water resources in the senegal river basin

ML. Mbaye (1) ; A. Haensler (2) ; S. Hagemann (3) ; AT. Gaye (1)

(1) Université Cheikh Anta Diop, Ecole Supérieure Polytechnique, Fann-Dakar, Senegal; (2) Climate Service Center, Hamburg, Germany; (3) Max Planck Institute for Meteorology, Hamburg, Germany

In this study we assess the impact of climate change on water resources by using uncorrected and bias corrected data of the regional climate model REMO simulations over the Senegal River Basin (SRB). Both simulations were used as input of the Max Planck Institute for Meteorology - Hydrometeorological Model (MPI-HM) over the Upper Senegal Basin (USB).

Applying the bias correction simulations of present day climate (1971–2000) substantially improved for both temporal and spatial variations of the analyzed climate parameters (precipitation, temperature) when compared to observations and independent station data. Additionally, the bias corrected input give better representation of the mean river flow regimes and the 10th (low) and 90th (high) flows at the outlet of the USB.

For the future, the regional climate model projections for precipitation show a general decrease by the end of 21st century (2071–2100) for both scenarios (RCP4.5 and RCP8.5 Representative Concentration Pathways) and datasets in the majority of the basin, except the Guinean highlands where slight increase is found. In case of the potential changes of the maximum number of dry days and wet days, the northern basin is likely to face the most projected increase of dry days and decrease of wet days, although slight increase of heavy rainfall is found with similar spatial patterns in both data. Higher decadal variability of the maximum 5-day precipitation with the uncorrected in RCP8.5 is projected, while uncorrected and bias corrected data depict similar temporal variability for extremely wet days. Furthermore, a general temperature increase is projected over the entire basin for both scenarios, but more pronounced under the RCP8.5

scenario. Warm night's percent is found to be higher than warm day's percent. As for the potential changes of the basin's hydrology, a general decrease of river discharge, runoff, actual evapotranspiration, soil moisture is found under RCP4.5 and RCP8.5 in all simulations. The decrease is higher under RCP8.5 with uncorrected data in the northern basin. However, there are some localized increases in some parts of the basin (e.g Guinean Highlands). Furthermore, the available water resources are projected to substantially decrease by more than -50% in the majority of the basin for all data, except the Guinean highlands where no change is projected.

The impact of the bias correction on the projected climate change signal, affects mainly the magnitude of the signal rather than its direction of change although some alteration may occur in particular months and localities.

# The main projections of the West African monsoon : mean climate, seasonal cycle, extreme rainfall events

PA. Monerie (1) ; E. Sanchez-Gomez (1) ; J. Boé (1)

(1) CERFACS, Toulouse, France

The main responses of the climate change effect on the West African Monsoon is evaluated in terms of mean climate and intense rainfall events with CMIP5 models under the rcp8.5 emission scenario. We examine the projections and how they are related to the mean biases of the historical model simulations. The projections range from an increase to a decrease of rainfall amounts, exhibiting a large spread. These differences are due to radiative forcing ranging from 4 to 6°C in the Saharan desert and to feeding (export) of moisture from the mid-level of models exhibits a decrease (increase) of rainfall over the western (central) Sahel along with more subsidence (air ascent) and a southward location of the AEJ (more moisture flux convergence). The extreme indices change exhibit a more extreme Sahelian climate, but the results remain strongly model-dependant. This study draw up a catalogue of the model projections in order to allow a selection of models for impact studies.

# The impacts of environmental variability and model uncertainty in disease prediction

A. Morse (1) ; A. Jones, (1) ; C. Caminade (1) ; J. Leedale, (1) D. Macleod, (1)

(1) University of Liverpool, Geography and Planning, Liverpool, United Kingdom; (2) University of Oxford, Physics, Oxford, United Kingdom

Modelling vector-borne diseases using dynamical models driven by climate and environmental variables is a complex task. The models require both accurate predictions of the seasonally varying values of environmental drivers and their correct variability across a range of time scales from days to decades. Whereas, the model's internal structures and the parameter settings for key processes have to develop the correct sensitivities to the external driving variables. The relationship between these two areas develops the inherent uncertainties in the model outcomes especially when driven with an ensemble of outputs from climate models.

Most of these detailed diagnosis runs and investigations are undertaken within the initial development phases of the models. Detailed diagnoses are perhaps even more challenging than the initial model development and construction. Once the model becomes established, in its use, the pace and quantity of model runs required in large collaborative projects make it difficult to find time and resource to allow detailed in depth diagnosis. Development of partially automated diagnosis methods and visualisation needs to be supported with the ever increasing loading of climate model runs that are being undertaken by disease modelling groups.

This paper will discuss two models the established Liverpool Malaria Model (LMM) and the recently developed Liverpool Rift Valley fever model (LRVF). Using the LMM we explore the relationship between seasonal average climate and malaria risk, which remains largely unquantified.
We also investigate key uncertainties in the malaria model, by introducing variability in parts of the model formulation. Results are visualized as location specific impact surfaces: easily integrated with ensemble seasonal climate forecasts. Using the LRVF, which is based on but much more complex than LMM, having two dynamic vector models and a dynamic age stratified host model. One main task in its development was parameterising the two different behaviours of the two vectors correctly in the model. In that, Culex spp. mosquitoes are the amplifying vector that, in the model, and only show significant spikes in population dynamics and EIR following flooding and a sizable Culex spp. population. The Culex spp. were infected from a substantial number of infectious hosts in the model simulation. These host infections came from Aedes spp. mosquitoes whose relationship with rainfall is more complex and gain infection through vertical transmission.

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## How farmers permanently adapt to climate evolution by testing new options and caring for food security: case of long-cycle sanyo millet comeback in Serer area in Senegal

B. Muller (1); L. Richard (2); P. Kouakou (3); S. Arame (4)
(1) CIRAD, Bios umr agap, Montpellier, France; (2) IRD, Umr 151 urd/amu, Marseille, France; (3) ISRA-CERAAS, Thies, Senegal; (4) UCAD, Département de géographie, Dakar, Senegal

During the last decade, Serer farmers of the Sine region in the central and western part of Senegal have started to grow again the sanyo millet (Pennisetum glaucum), a long-cycle (110-140 days) and photoperiodic traditional variety that had disappeared for 30 years from this region due to the rainfall decrease which has affected the Sahelian and Sudano-Sahelian zones starting from 1970, leaving only the short-cycle (90 days) souna millet in the fields. We made the assumption that the reintroduction of the sanyo millet could be an agronomic "marker" of the increase in rainfall observed in the mid-1990s (Salack and al., 2011) attesting to the capacity of farmers to adapt to the evolution of their environment. We wanted to check, however, whether this necessary climatic opportunity was sufficient to explain farmers choices.

We investigated how important was the sanyo comeback in local farming systems, its geographical diffusion, and its biophysical, agroecological, social and cultural drivers. We carried out (a) simulations of souna and sanyo annual development during the 1950-2013 period using the Sarrha©Cirad model; (b) several Focus Group Discussions with farmers; (c) a large survey by questionnaire on farming systems among 1,061 farms in the 30 villages of the IRD human and health observatory zone of Niakhar (monitored since 50 years); and (d) a rapid survey in 240 villages of the region located between Bamby and Dioroul in the North and Fatich in the South (about 1000 km) on whether the sanyo millet was grown and its date of reintroduction. The Sarrha©Cirad crop model was parameterised according to previous works. Survey data were carefully analysed using relevant statistics to assess the factors underlying sanyo reintroduction.

Crop model simulations confirmed that sanyo reappearance is due to the recent rainfall improvement which allows getting again grains with this variety whereas since 1970s production was not only possible with souna. But simulations also show that sanyo yields remain very risky due to the rainfall interannual variability whereas souna yields are higher and surer. They also show that sanyo provides important biomass (stalks and straw). Farmers comments and surveys data analysis complement and confirm the results of the simulations. First, peasants report that they prefer the taste of sanyo and souna and above all the quality of its stems rather than those of souna. In addition, adopting sanyo does not require any specific know-how or investment as it is grown like souna. Its qualities explain why it has quickly spread throughout the area. Sanyo was present in 61% of the sites surveyed in 2013 compared with 23% in 2000. But farmers stress that it is a risky cultivation and that they will not endanger their food security by substituting souna with sanyo. Souna and groundnuts still remain the main staple and cash crops, respectively. They also deplore that sanyo (similarly to souna) cannot provide cash, unlike groundnuts or watermelon that

has also expanded in recent years. Statistical analyses highlight some social and family influences since farmers belonging to the "warrior caste" and those whose fathers formerly cultivated sanyo are more likely to cultivate it. But "land resources" appear to be the key factor. Yet, farmers explain they would plant fields dedicated to sanyo only if they were sure to produce enough souna. This is why sanyo is mainly cropped in association with souna, in an average proportion of 1 line of sanyo for 4-5 lines of souna. Moreover farmers point out that they would easily stop sanyo if they had other opportunities, particularly if they provide cash. Thus, despite its spectacular diffusion, sanyo cover very little surfaces; in the zone of Niakhar it was present in 2013 on 2.8% of the cropped areas and on 7.3% of millet areas.

Sanyo reappearance and its important and rapid diffusion is clearly an economic "marker" of the recent climate evolution (rainfall increase) observed in Senegal. It attests to the adaptive capacity of farmers to quickly and autonomously adapt to the evolution of their environment by permanently looking and trying new options, but underlines how cautious they are to not endanger their food security, and confirms that a climatic opportunity is not sufficient to account for farmers' choices. Comparisons can be made with recent watermelon emergence in the same area and developments of maize and rainfed rice areas in the southern areas of Senegal, which have been enabled by the rainfall evolution but benefit of solid economical drivers.

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## Economic futures of African family farms in the face of climate change: addressing three big questions through integrated assessment with a Tanzanian case

K. Mutabazi (1)

(1) Sokoine University of Agriculture, Agricultural Economics and Agribusiness, Morogoro, Tanzania, United Republic of

Family farms have sustained the livelihood and development of most Sub-Saharan African countries and will continue to do so for a foreseeable future. Much of the development literature has widely addressed the economic futures of African family farms in the perspective of regional and global economic trends and trajectories - with limited attempts of scoping these futures in the context of climate change. Where such attempts have been made, the assessments overly short of an integrated approach that utilizes recent advances of interfaced biophysical and economic modeling. Based on a sample of 168 family farms in the semi-ard and sub-humid farming systems of Wami-Ruvu Basin in Tanzania, the paper applies an integrated climate change assessment to address the following three big questions: How the African family farms will be impacted by climatic change; How they could continue with business as usual? What will be the impacts with foreseen development pathways without adaptation? What will be the impacts with foreseen development pathways with adaptation?

P-3330-60

## Trends in daily extreme precipitation and temperature indices over Ghana from 1980 to 2011

F. Nkrumah (1); NAB. Klutse (2)

(1) University of Cape Coast, Physics, Cape Coast, Ghana;

(2) Ghana Space Science and Technology Institute, Remote Sensing, GIS, Climate, Accra, Ghana

In this study, the spatial and temporal patterns of the variables of the indices of precipitation extremes, on the basis of daily data and its association with climate change at twenty synoptic stations in Ghana over the period 1980-2011 were analyzed. Daily temperature (maximum and minimum) and precipitation data over the period of 1980 to 2011 were used. Data were quality controlled, and processed into indices of climate extremes, and the indices were calculated using RCLimDex which is based on R software and is developed and maintained by the Climate Research Branch of Meteorological Service of Canada. From 1980 to 2011 hot days and nights have increased, leading to a decrease in cold days and nights. Except simple daily intensity (SDII) index station, other precipitation indices
do not illustrate statistically significant trends across the whole region. The precipitation indices show a general increasing trend in annual rainfall (PRCPTOT), heavy precipitation days (R10mm) and very heavy precipitation days (R20mm) with an increasing trend also in the simple daily intensity observed. However, the results of other precipitation indices indicate an unstable trend in the intensity of rainfall. In spite of the results of the precipitation indices it is noticed that more intense rainfall is observed over short periods although the temperature trends increase sharply and dramatically. Therewith, the climate of the region is becoming warmer.

P-3330-61

Revivifying a 13th Century Craft to
Enhance Community-based Adaptation
through Ecosystems and Farm-lands Resi-
lience enhancement in Uganda

D. Nkwanga (1)

(1) Nature Palace Foundation, Programs, Kampala, Uganda

Bark-cloth making is a 13th Century craftsmanship steeped in ancient culture and tradition where it played significant cultural, financial, social and conservation roles. Uganda's bark-cloth, a unique fabric proclaimed by UNESCO as 'a masterpiece of the world's intangible heritage' and indigenous textile production craft, is produced from Ficus natanslensis. The F. natanslensis trees are cultivated on the farm in an agro-forestry system intercropped with other crops. The bark of the tree is harvested, without harming the tree, to make an environmentally-friendly, renewable material. Where the trees have been cultivated it has been found that crops like coffee, bananas and others are able to withstand dry spells better than where it is not cultivated. Beyond this F. natanslensis branches are harvested to provide a sustainable supply of firewood making households energy-secure and reducing on deforestation cooking energy being one of the major causes of deforestation and environmental degradation; leaves of the trees provide fodder for domestic animals; and, the sale of bark-cloth provides a passive income that is always accessed by households even if the weather conditions are not favorable for seasonal crops. The presentation discusses the potential of bark-cloth making as a stimulus to long-term community-based adaptation.

P-3330-62

Climate change and surface water resource mobilization for agricultural purposes in the okpara basin (west Africa)

R. Ogouwale (1)

(1) Université d'Abomey-Calavi, Laboratoire Pierre PAGNEY, ABOMEY-CALAVI, France

This research aims at evaluating the ongoing impacts of climate change on water resources availability in the Okpara basin. It seeks to identify water resources vulnerability in the basin in regard to the ongoing climate changes. These changes are characterized by variability in climate indicators.

To identify current climate change impacts, climate data of the normal (1971-1970) and (1971-2000) are assessed and compared. The rainfall averages have been used to determine differences (gaps) between the two above-mentioned normal. The data generated at different levels have been translated into relative values. As for temperatures, warming indicators are identified on the basis of calculation of the differences (° C) between the said normal (1941-1970 and 1971-2000). Besides, considering the evolution of climate parameters on the target period, 1971-2000, their future trend has been estimated.

Comparative analysis of the rainfall data between normal 1971-2000 and 1941-1970, shows overall that rainfall has decreased by 16 and 28% in the Okpara basin. During this very period of time, temperatures have increased overall by +1°C in the basin.

This has led to a degradation of water resources in the basin, which has resulted in the Okpara River's flows downfall. In fact, analysis of the hydrological flow rate over the period 1965-2000 shows an overall downward trend of about 20-25% during July, August, September

and October, which consequently reduces water resources availability in the basin.

On the basis of projections and events considering the period 1971-2000, temperatures will be rising between 1.5 and 2°C in the basin by 2050. The fall in rainfall would be between 11 and 30%. As for river flow, during the same period, the decline will increase up to 30% by 2025 and between 40% by 2050. If this trend is not reversed, we will be experiencing a decrease of water availability in the basin.

In this increasingly climate dryness context, potential reduction of surface water resources disrupts the performance of ecological and socioeconomic systems. Facing this situation, efforts to mobilize surface water for agricultural purposes are the main measures for adapting to climate impact hazards in the basin. These efforts should be continued and backed up for a sustainable economic production.

P-3330-63

Challenges of climate change in Southeas-
tern, Nigeria: Sustainable containment
measures

E. Okoyeh (Okoro) (1)

(1) Nnamiدي Azikiwe University Awka, Nigeria, Dept. of Geological Sciences, Awka, Anambra, Nigeria, Federal Republic of

Climate change, a global phenomenon has recorded great
significant in sub-Sahara Africa and Nigeria in particular.
The total environment of land, water and air are under
the severe threat of climate change challenges (CCC). The
ecological hazards of gully erosion and landslide ravaging
Southeastern, Nigeria through geogenic/anthropogenic in
origin have been exacerbated by increasing impacts of
climate change. The well established variation in the onset
and cession of rainfall attributed climate change has
significant implication on water availability, water quality,
ecological hazards, vegetation cover, food security and
public health. The torrential rainfall with attendant huge
runoff results in flooding. The impacts of climate change
induced flooding is significant in rural, semi urban and
urban areas of southeastern, Nigeria. Loss of farmland
and water supply sources with impact on food and water
security respectively has been recorded. Standard of living
and sustainable socioeconomic developments are hindered
due to climate change challenges (CCC) in Southeastern,
Nigeria. Outbreak of water borne diseases especially
in the river rein areas is a recurrent trend affecting poverty
alleviation and capacity building. Siltation of rivers, lakes
and streams is commonplace exacerbating water scarcity
and sustainable development. Heavy rainfall that initiates
the development of new gully erosion and landslide sites
and widening of existing ones is a consequence of climate
change challenge (CCC) in the area. Over 750 active
gully erosion and landslide sites have been recorded in
Southeastern, Nigeria with depth ranging from 2 m to
> 300 m and length from 25 m to 2.9 km. Removal of
sediments from gully and landslide sites and deposition of
same in surface water sources has resulted in the siltation
of most rivers and lakes in the area. This is complimented
by the excessive heat and temperature of above 400°C
during the dry season to cause total loss of some surface
water bodies. The impact of desert encroachment also
abounds with the rate of southwards advancement of
desert increasing seasonally. The degradation of the
rainforest vegetation to savanna grassland with remnant
of rainforest vegetation only around water courses
has generated serious concern to all stakeholders in
recent time. The rainforest vegetation of southeastern,
Nigeria has been severely degraded exposing the arable
lands to the scourging effects of climate change. These
climate change challenges (CCC) disproportionately affect
women and children in the developing economies such
as Southeastern, Nigeria. There is need for the creation
of awareness about adverse effects of climate change on
the environment and terms of water, water scarcity,
development, vegetation degradation and food security.
Tree planting campaign of planting two trees at the
removal of one should be promoted and given the wide
publicity it deserves. Laws prohibiting illegal tree cutting
and building along flood plains should be constituted with
the political will to punish defaulterers. Establishment of
research centers for researches on climate change related
issues is also recommended.
## Use of the CORDEX simulations to assess the impact of +2/4 K climate change on crop yields in Subsaharan Africa

B. Parkes (1); B. Sultan (2); P. Ciais (3)

(1) UPMC, LOCEAN, Paris, France; (2) IRD, LOCEAN, Paris, France; (3) IPSL, Lsce, Gif sur Yvette, France

The population of Subsaharan Africa is projected to increase during the 21st century. This population increase needs to be matched with an increase in the amount of food available.

The IPCC AR5 used the CMIP5 models to assess future climate impacts on a regional and global scales. Alongside the development of AR5 recent publications have changed approach to a «not if, but when» approach to passing certain climate thresholds. The +2/4/6 K global temperature changes are examples of these thresholds. The Representative Concentration Pathways (RCPS) used in AR5 were simulated using different inputs and models and therefore reach temperature thresholds at different times. Here we present the projected change in crop yields in Subsaharan Africa for global average temperature changes of +2/4 K.

In tropical regions the ability of Global Climate Models (GCMs) to reproduce realistic weather patterns is known to be poor, this is largely due to the low resolution of climate models being unable to simulate the weather conditions accurately. To counteract the low resolution issues, the Coordinated Regional Climate Downscaling Experiment (CORDEX) used several Regional Climate Models (RCMs) to focus on specific geographical regions, including Africa, South East Asia and Europe. The higher resolution RCMs are better at simulating accurate weather and can be bias corrected to remove any large inconsistencies. Models which represent the range of the CORDEX simulations have been used to drive the ORCHIDEE-Crop model. The ORCHIDEE-Crop model is the crop specific version of the ORCHIDEE land surface model. The crop specific version has been tuned to produce accurate yields with various crops including maize, wheat and rice.

In this work we investigate how maize yields will change in Subsaharan Africa at +2/4 K with data from the CORDEX experiments. Changes in yields and the expenses to different stresses will be used to assess how the future climate will affect the populations in Subsaharan Africa.

## Observed long-term land cover vs climate impacts on the West African hydrological cycle: lessons for the future ?

C. Peugeot (1); S. Galle (2); M. Grippa (3); I. Bouzou Moussa (4); B. Capellaure (5); J. Demarty (1); E. Mougi (6); L. Descroix (7); T. Lebel (8); C. Dardel (6); G. Favreau (10); P. Hiernaux (9); L. Kergoat (6); Y. Nazoumou (10); J.P. Vandavaere (11); L. Séquis (1); L. Leroux (12); M. Malam Abdou (13); V. Orekan (14); J. Oszwald (15)

(1) IRD, Hydrosciences montpellier (hsm), Montpellier, France; (2) IRD, LTHE, 30041 Grenoble Cedex, France; (3) Université de Toulouse, Get, Toulouse, France; (4) Abdou Moumouni (1); Abidjan, Abidjan, Abidjan, Niger, Republic of; (5) IRD, Hydrosciences montpellier, Montpellier, France; (6) GET, Umr cnrs 5563, Toulouse, France; (7) UMR PALOC, Lmi pateo, campus international de recherches ucid/uid de hann, Dakar-Hann, Senegal; (8) IRD, LTHE, 38041 Grenoble Cedex, France; (9) retired from CNRS GET, Caylus, France; (10) Université Abdoumoumouni, Niamey, Niger, Republic of; (11) Université de Grenoble, Grenoble, France; (12) CIRAD, Umr tetis, Montpellier, France; (13) Université de Zinder, Dzinder of geography, Zinder, Niger, Republic of; (14) Université d'Abomey Calavi, Labee, Cotouon, Benin; (15) Université Rennes-2, Umr letg, Rennes, France

West Africa has experienced a long lasting, severe drought as from 1970, which seems to be attenuating since 2000. It has induced major changes in living conditions and resources over the region. In the same period, marked changes of land use and land cover have been observed: more clearing, more clearing and more drilling, higher demographic growth rates, and ecosystem evolutions driven by the

rainfall deficit. Depending on the region, the combined effects of these climate and environmental changes have induced contrasted impacts on the hydrological cycle. In the Sahel, runoff and river discharges have increased despite the rainfall reduction ("less rain, more water", the so-called «Sahelian paradox»). Soil crusting and erosion have increased the runoff capacity of the watersheds so that it outperformed the rainfall deficit. Conversely, in the more humid Guinean and Sudanian regions to the South, the opposite (and expected) "less rain, less water" behavior is observed, but the signature of land cover changes can hardly be detected in the hydrological records.

These observations over the past 50 years suggest that the hydrological response to climate change can not be analyzed irrespective of other concurrent changes, and primarily ecosystem dynamics and land cover changes.

There is no consensus on future rainfall trend over West Africa in IPCC projections, although a higher occurrence of extreme events (rainstorms, dry spells) is expected. An increase in the need for arable land and water resources is expected as well, driven by economic development and demographic growth. Based on past long-term observations on the AMMA-CATCH observatory, we explore in this work various future combinations of climate vs environmental drivers, and we infer the expected resulting trends on water resources, along the west African eco-climatic gradient.

## Regional climate modelling of the West African Monsoon regime and its use for impacts and adaptation studies in Sahelian countries

ED. Poan (1); P. Gachon (1); G. Duymes (1); E. Diaconescu (2); R. Laprise (3); C. Saad (1); S. Seidou (4)

(1) ESCER-IUQAM, Atmospheric Sciences, Montréal, Québec, Canada; (2) Environment Canada, Canadian centre for climate modelling and analysis, Montréal, Québec, Canada; (3) Université du Québec, Earth and atmospheric sciences, Montréal, Canada; (4) Centre Régional ARGYMET/CILSS, Niamy, Niger, Republic of

In the context of climate change, increasingly applications are asked to better adjust adaptation and mitigation purposes at regional and local levels. Regional Climate Models (RCMs) appear as useful tools to downscale meteorological and climate information and make it more meaningful to fulfill end-user needs. In the framework of the International Research Initiative on Adaptation to Climate Change (IRIACC) - Faire face aux Changements Ensemble (FACE), a joint effort has been carried out to investigate different aspects and repercussions of climate change on health and agriculture over the Sahelian region in view of various RCM projections. The presentation will focus on the ability of RCMs to improve the climate information at different time and space scales, with respect to large-scale boundary conditions, in particular their performance regarding the intrascale variability of the monsoon regime. Precipitation onset, which significantly affects the agricultural activities, meteorological-scale rain systems as well as daily precipitation indices (related to occurrence, intensity, duration of daily events) are compared with the recent past observations showing a better agreement compared to global reanalyses and global climate models simulations. However, to be really helpful and oriented to specific applications, some aspects of RCMs, namely their physical parameterizations and/or simulated processes at the scale of meteorological systems, need improvements.

## Defining genotypic adaptation targets via crop-climate modelling

J. Ramirez-Villegas (1); K. Ann-Kristin (2); A. Challinor (3)
(1) University of Leeds and CCAFS, School of earth and environment and ccafs flagship 1 Leeds, West Yorkshire, United Kingdom; (2) University of Leeds, School of earth and environment, Leeds, West Yorkshire, United Kingdom; (3) Univ. Leeds, Ccafs, Leeds, United Kingdom

Recent literature indicates that, in the absence of adaptation, on average, climate change would reduce agricultural yields globally by 2-10 % per degree of warming. Crop breeding will likely play a critical role in