rlacombe/ClimateX huggingface dataset:
An equivalent approximate description using specific years would be ‘since the 1980s’.Model Evaluation, Technical Infrastructure and the Interactive Atlas The regional performance of CMIP6 global climate models (GCMs) has improved overall compared to CMIP5 in simulating mean temperature and precipitation, though large errors still exist in some regions (IPCC AR6_WGI, confidence: high)
In particular, regional climate models (RCMs) with polar-optimized physics are important for estimating the regional and local surface mass balance and are improved compared to reanalyses and GCMs when evaluated with observations (IPCC AR6_WGI, confidence: high)
There is still a lack of high-quality and high-resolution observational data to assess observational uncertainty in climate studies, and this compromises the ability to evaluate models (IPCC AR6_WGI, confidence: high)
Atlas.4.1.2 Findings From Previous IPCC Assessments The most recent IPCC reports, AR5 and SR1.5 (Christensen et al., 2013; Hoegh-Guldberg et al., 2018), state that over most parts of Africa, minimum temperatures have warmed more rapidly than maximum temperatures during the last 50 to 100 years (IPCC AR6_WGI, confidence: medium)
In the same period, minimum and maximum temperatures have increased by more than 0.5°C relative to 1850–1900 (IPCC AR6_WGI, confidence: high)
According to SROCC, eastern Africa like other regions with smaller glaciers is projected to lose more than 80% of its glaciers by 2100 under RCP8.5 (IPCC AR6_WGI, confidence: medium)
The consequence of increased temperature and evapotranspiration, and decreased precipitation amount, in interaction with climate variability and human activities, have contributed to desertification in dryland areas in sub-Saharan Africa (medium confidence) as reported in SRCCL (Mirzabaev et al., 2019).Atlas.4.2 Assessment and Synthesis of Observations, Trends and Attribution Figure Atlas.11 shows observed trends in annual mean surface temperature and indicates it has been rising rapidly over Africa from 1961 to 2015 and with significant increases in all regions of 0.1°C–0.2°C per decade and higher over some northern, eastern and south-western regions (IPCC AR6_WGI, confidence: high)
Southern African rainfall shows a significant downtrend of –0.013 mm day–1 year –1 in recent decades and –0.003 mm day–1 year –1 for longer periods during 1900–2010 (IPCC AR6_WGI, confidence: low)
Enhanced rainfall intensity since the mid-1980s over the Sahel (Maidment et al., 2015; Sanogo et al., 2015) is associated with increased greenhouse gases suggesting an anthropogenic influence (IPCC AR6_WGI, confidence: medium)
Moreover, later onset and earlier cessation of eastern Africa rainfall is associated with a delayed and then faster movement of the tropical rainband northwards during the boreal spring and northward shift of the Saharan heat low (Wainwright et al., 2019), driven by anthropogenic carbon emissions and changing aerosol forcings (IPCC AR6_WGI, confidence: medium)
However, decadal natural variability from SST variations over the Pacific Ocean has also been associated with the drying trend of East Africa (Wang et al., 2014; Hoell et al., 2017) with an anthropogenic-forced rapid warming of Indian Ocean SSTs (IPCC AR6_WGI, confidence: medium)
The rate of surface temperature increase has generally been more rapid in Africa than the global average and by at least 0.1°C–0.2°C during 1961–2015 (IPCC AR6_WGI, confidence: high)
Minimum temperatures have increased more rapidly than maximum temperatures over inland southern Africa (IPCC AR6_WGI, confidence: medium)
Since 1970, mean temperature over East Africa has shown an increasing trend but showed a decreasing trend in the previous 40 years (medium confidence).The Horn of Africa has experienced significantly decreased rainfall during the long rains season from March to May (high confidence) and drying trends in this and other parts of Africa are attributable to oceanic influences (IPCC AR6_WGI, confidence: high)
The enhanced rainfall intensity over the Sahel in the last two decades is associated with increased greenhouse gases indicating an anthropogenic influence (IPCC AR6_WGI, confidence: medium)
Relative to the late 20th century, annual mean temperature over Africa is projected to rise faster than the global average (IPCC AR6_WGI, confidence: very high)
The central interiors of southern and northern Africa are likely to warm faster than equatorial and tropical regions (IPCC AR6_WGI, confidence: high)
There are contrasting signals in the projections of rainfall over some parts of Africa until the end of the 21st century (IPCC AR6_WGI, confidence: high)
However, northern Africa and the south-western parts of South Africa are likely to have a reduction in precipitation under higher warming levels (IPCC AR6_WGI, confidence: high)
Over Western Africa, rainfall is projected to decrease in the western Sahel sub-region (medium confidence) and increase in the central Sahel sub-region (low confidence) and along the Guinea coast sub-region (IPCC AR6_WGI, confidence: medium)
Rainfall amounts are projected to increase over Eastern Africa (IPCC AR6_WGI, confidence: medium)
Southern Africa is projected to have a reduction in annual mean rainfall but increases in rainfall intensity by 2100 (IPCC AR6_WGI, confidence: medium)
Precipitation trends over East Asia show considerable regional differences (IPCC AR6_WGI, confidence: medium)
Atlas.5.1.5 Summary In East Asia annual mean temperature has been increasing since the 1950s (IPCC AR6_WGI, confidence: high)
Trends of annual precipitation show considerable regional differences with areas of both increases and decreases (medium confidence), and with increases over north-west China and South Korea (IPCC AR6_WGI, confidence: high)
Agricultural intensification through oasis expansion in Xinjiang region has increased summer precipitation in the Tian Shan mountains (IPCC AR6_WGI, confidence: high)
The SR1.5 noted that future, higher levels of warming lead to greater impacts in key systems such as the Siberian ecosystems, identified as one of the threatened systems (‘Reason for Concern 1 – RFC1’; Hoegh-Guldberg et al., 2018) with impacts at 2°C expected to be greater than those at 1.5°C (IPCC AR6_WGI, confidence: medium)
In addition, significant warming in the last decade has halved the cooling trend in southern WSB from –0.6°C per decade during 1976–2012 to –0.3°C per decade during 1976–2018 (IPCC AR6_WGI, confidence: high)
The latter reanalysis also underestimates summer precipitation and shows large wet biases over north-east Asia during spring and underestimates mean seasonal temperature over north-east Asia in spring (MAM), autumn (SON), and winter (DJF), but overestimates it in summer (JJA) compared with the CRU dataset (IPCC AR6_WGI, confidence: medium)
For CMIP5, models with higher resolution do not always perform better than those with lower resolutions (IPCC AR6_WGI, confidence: medium)
The highest warming has been found in spring in ESB and RFE, strengthening from south to north with linear trends of 0.8°C–1.2°C per decade over the 1976–2014 period (IPCC AR6_WGI, confidence: high)
A temperature decrease was identified just in winter in the southern part of WSB and ESB as a result of natural variability, but halved from –0.6°C per decade in 1976–2012 to –0.3°C per decade for the longer 1976–2018 period due to recent warmer winters (IPCC AR6_WGI, confidence: high)
Over North Asia annual precipitation increases with estimated trends of 5–15 mm per decade in the 1976–2014 period have been recorded with an exception over the Kamchatka and the Chukchi peninsulas, where decreases of up to –20 mm per decade in the same period have been found (IPCC AR6_WGI, confidence: medium)
Most of the CMIP5 and some CMIP6 GCMs overestimate the annual mean air temperature and precipitation over the North Asia region (IPCC AR6_WGI, confidence: medium)
GCMs generally represent the observed decadal temperature trend (medium confidence) and biases primarily come from the winter (DJF) season (IPCC AR6_WGI, confidence: high)
Sparsity of observational data particularly in the northern part of ESB and the whole of the RFE results in low confidence in the assessments of model performance in North Asia.Surface air temperature and precipitation in North Asia are projected to increase further (IPCC AR6_WGI, confidence: high)
CMIP5 models projected for the 21st century a significant increase in temperature over South Asia (high confidence from robust evidence) and in projections of increased summer monsoon precipitation (IPCC AR6_WGI, confidence: medium)
The Indian summer monsoon circulation was found to have weakened, but this was compensated by increased local atmospheric moisture content leading to more rainfall (IPCC AR6_WGI, confidence: medium)
The annual average of daily maximum and minimum temperatures has increased over almost all Pakistan with a faster increasing trend in the south (IPCC AR6_WGI, confidence: high)
Concurrently, the frequency of heavy precipitation events has increased over India, while the frequency of moderate rain events has decreased since 1950 (IPCC AR6_WGI, confidence: high)
A global modelling study with high resolution over South Asia (Sabin et al., 2013) indicated that a juxtaposition of regional land-use changes, anthropogenic-aerosol forcing and the rapid warming signal of the Equatorial Indian Ocean was crucial to simulate the observed Indian summer monsoon weakening in recent decades (IPCC AR6_WGI, confidence: medium)
A dipole-like structure in summer monsoon rainfall trends is observed over the northern Indo-Pakistan area with significant increases over Pakistan and decreases over central north India resulting from strengthening (weakening) of vertically integrated meridional moisture transport over the Arabian Sea (Bay of Bengal) (IPCC AR6_WGI, confidence: low)
Observations and model simulations showed that the increasing temperature of frozen grounds is leading to thawing and reduced depth of permafrost, with further significant reductions projected under future global warming scenarios (IPCC AR6_WGI, confidence: medium)
With continued global warming and anticipated reductions in anthropogenic aerosol emissions in the future, CMIP5 models project an increase in the mean and variability of summer monsoon precipitation over India by the end of the 21st century, together with substantial increases in daily precipitation extremes (IPCC AR6_WGI, confidence: medium)
Atlas.5.3.5 Summary Mean, minimum and maximum daily temperatures in South Asia are increasing and winters are getting warmer faster than summers (IPCC AR6_WGI, confidence: high)
Over the same time periods CMIP6 models project an increase in annual precipitation in the range 14–36% under SSP5-8.5 and 0.4–16% under SSP1-2.6 (IPCC AR6_WGI, confidence: medium)
Over South East Asia, there has been a significant increase in the amount of precipitation and its extremes with La Niña episodes in the past decades, especially during the winter monsoon period (IPCC AR6_WGI, confidence: high)
Figure Atlas.11 shows trends in mean temperature and precipitation during 1961–2015 for two global datasets, indicating a significant overall warming over South East Asia (high confidence), with higher rates of warming in Malaysia, Indonesia, and the southern areas of mainland South East Asia (IPCC AR6_WGI, confidence: low)
Annual mean precipitation trends (Atlas.1.4.1 and the Interactive Atlas, which includes the regional dataset Aphrodite) over the region are mostly not significant except for increases over parts of Malaysia, Vietnam and the southern Philippines (IPCC AR6_WGI, confidence: medium)
Atlas.5.4.3 Assessment of Model Performance Performance in simulating rainfall over South East Asia varies among CMIP5 GCMs (IPCC AR6_WGI, confidence: high)
Projections of future rainfall changes are highly variable among sub-regions of South East Asia and among the models (IPCC AR6_WGI, confidence: high)
Atlas.5.4.5 Summary It is virtually certain that annual mean temperature has been increasing in South East Asia in the past decades while changes in annual mean precipitation are less spatially coherent though with some increasing trends over parts of Malaysia, Vietnam and the southern Philippines (IPCC AR6_WGI, confidence: medium)
Projected changes in rainfall over South East Asia vary, depending on model, sub-region and season (high confidence), with consistent projections of increases in annual mean rainfall from CMIP5 and CMIP6 over most land areas (medium confidence) and decreases in summer rainfall from CORDEX projections over much of Indonesia (IPCC AR6_WGI, confidence: medium)
WCA includes high mountains with enhanced warming above 500 m where, regardless of the emissions scenario, decreases in snow cover are projected due to increased winter snowmelt and more precipitation falling as rain (IPCC AR6_WGI, confidence: high)
This increases the uncertainty in both temperature and precipitation trends, particularly for elevated areas (IPCC AR6_WGI, confidence: high)
A strong increase in annual surface air temperature of 0.27°C–0.47°C per decade has been found over WCA between 1960 and 2013 (IPCC AR6_WGI, confidence: very high)
The plateau of Iran has experienced significant increases in the average monthly values of daily maximum and minimum temperatures with spatially varying rates of 0.1°C–0.3°C up to 0.3°C–0.4°C per decade and greater spatial variation in minimum temperatures (IPCC AR6_WGI, confidence: high)
Over the elevated part of eastern WCA precipitation increases in the range of 1.3–4.8 mm per decade during 1960–2013 were observed (IPCC AR6_WGI, confidence: very high)
A decreasing trend of precipitation is reported for ARP with the mean value of –6.3 mm per decade (range of –30 mm–16 mm) for the period 1978–2019 (IPCC AR6_WGI, confidence: low)
The same decreasing trend in precipitation totals and an increasing trend in the number of consecutive dry days are found for most of the Iranian Plateau (IPCC AR6_WGI, confidence: medium)
RCM simulations using the CORDEX-MENA domain reproduce the main features of the mean surface climatology over ARP with moderate biases (IPCC AR6_WGI, confidence: high)
Annual precipitation change over ARP since 1970 is estimated at –6.3 mm per decade (and in the range of –30 to 16 mm per decade) and over WCA is generally not significant except over the elevated part of eastern WCA where increases between 1.3 mm and 4.8 mm per decade during 1960–2013 have been observed (IPCC AR6_WGI, confidence: very high)
In mountainous areas, the scarcity and decline of the number of observation sites since the end of the former Soviet Union in 1991 increase the uncertainty of the long-term temperature and precipitation estimates (IPCC AR6_WGI, confidence: high)
Mean temperature biases in RCMs are within ±3°C in South West Asia, and annual precipitation biases are positive in almost all parts of the region, except over the ARP where they are negative in the wet season (November to April) and over WCA in winter and spring (from December to May) (IPCC AR6_WGI, confidence: medium)
Further warming over South West Asia is projected in the 21st century to be greater than the global average, with rates varying from 0.25°C to 0.8°C per decade depending on the season and scenario, and the maximum rates found in the northern part of the region in summer (IPCC AR6_WGI, confidence: high)
CMIP6 projected changes in annual precipitation totals are in the range of –3 to 29% (SSP1-2.6) and 12–107% (SSP5-8.5) in ARP (IPCC AR6_WGI, confidence: medium)
Strong spatio-temporal differences with overall precipitation decreases are projected in the central and northern parts of WCA in summer (JJA) with increases in winter (DJF) (IPCC AR6_WGI, confidence: medium)
For example, while annual rainfall has been significantly increasing in north-western Australia since the 1950s (very high confidence), it has been decreasing in the north-east of the South Island of New Zealand over 1950–2004 (IPCC AR6_WGI, confidence: very high)
Likewise, however, there is a projected increase in the frequency of drought in southern Australia (medium confidence) and in many parts of New Zealand (IPCC AR6_WGI, confidence: medium)
The AR5 reported mean sea levels have also increased in Australia and New Zealand at average rates of relative sea level rise of 1.4 ± 0.6 mm yr –1 from 1900 to 2011, and 1.7 ± 0.1 mm yr –1 from 1900 to 2009, respectively (IPCC AR6_WGI, confidence: very high)
The assessment found that the volume of ice in New Zealand has declined by 36–61% from the mid- to late 1800s to the late 1900s, while late-season significant snow depth has also declined in three out of four Snowy Mountain sites in Australia between 1957 and 2002 (IPCC AR6_WGI, confidence: high)
On the other hand, the volume of winter snow and the number of days with low-elevation snow cover in New Zealand are projected to decrease in the future (very high confidence), while both snow depth and area are projected to decline in Australia (IPCC AR6_WGI, confidence: very high)
It also reports on the vulnerability of some Australian communities and ecosystems to sea level rise, increases in the intensity and duration of marine heatwaves driven by human influence (IPCC AR6_WGI, confidence: high)
For a longer-term perspective based on high-quality regional datasets, Figure Atlas.20 shows Australasia has warmed over the last century (IPCC AR6_WGI, confidence: very high)
Snow cover is likely to decrease throughout the region at high altitudes in both Australia and New Zealand (IPCC AR6_WGI, confidence: high)
According to AR5 (Christensen et al., 2013), significant positive trends of temperature have been observed in Central America (IPCC AR6_WGI, confidence: high)
In addition, changes in climate variability and in extreme events have severely affected the region (IPCC AR6_WGI, confidence: medium)
El Niño and La Niña teleconnections are projected to move eastwards in the future (medium confidence), while changes in their effects on other regions, including Central America and the Caribbean is uncertain (IPCC AR6_WGI, confidence: medium)
Precipitation change is projected to vary between +10% and –25% (IPCC AR6_WGI, confidence: medium)
Jones et al., 2016a; Hidalgo et al., 2017), with the largest increases in the North American Monsoon region (IPCC AR6_WGI, confidence: high)
Positive trends in the duration of the MSD have been found in this region over the past four decades (IPCC AR6_WGI, confidence: low)
Particularly relevant for this region are increased model resolution and a better representation of the land surface processes (IPCC AR6_WGI, confidence: high)
Regional climate models (RCMs) forced with reanalyses and atmosphere-only global climate models provide simulations with a reasonably good performance over the core North American Monsoon region, mostly in NCA (IPCC AR6_WGI, confidence: high)
RCMs also reproduce the seasonal spatial patterns of temperature and the bimodal rainfall characteristics of the NCA, SCA and CAR (IPCC AR6_WGI, confidence: high)
RCM simulations in the region do not necessarily improve with the size of the domain, as important features of the regional circulation and key rainfall climate features, such as the CLLJ and MSD, are well represented for a variety of domains of different sizes (IPCC AR6_WGI, confidence: high)
Global and regional models consistently project warming in the whole region for the end of the century, under RCP4.5 and RCP8.5 for CMIP5 projections with greater warming for continental compared to insular territories, likely reaching values between 2°C and 4°C (IPCC AR6_WGI, confidence: high)
Atlas.7.1.5 Summary Significant warming trends between 0.2°C and 0.3°C per decade have been observed in the three reference regions of Central America in the last 30 years, with the largest increases in the North American Monsoon region (IPCC AR6_WGI, confidence: high)
Under moderate future emissions overall negative but non-significant precipitation trends are projected for the 21st century (IPCC AR6_WGI, confidence: low)
Atlas.7.2.1.2 Findings From Previous IPCC Assessments According to AR5 WGII Chapter 27 (Magrin et al., 2014), during the last decades of the 20th century, observational studies identified significant trends in precipitation and temperature in South America (IPCC AR6_WGI, confidence: high)
The AR5 WGI (Flato et al., 2013) noted that climate simulations from CMIP3 and CMIP5 models were able to represent well the main climatological features, such as seasonal mean and annual cycle (IPCC AR6_WGI, confidence: high)
Atlas.7.2.2 Assessment and Synthesis of Observations, Trends and Attribution Studies on climatic trends in South America indicate that mean temperature and extremely warm maximum and minimum temperatures have shown an increasing trend (IPCC AR6_WGI, confidence: high)
Regionally, analyses of temperatures point to an increased warming trend (IPCC AR6_WGI, confidence: high)
Andean temperatures showed significant warming trends, especially at inland and higher-elevation sites, while trends are non-significant or negative at coastal sites (IPCC AR6_WGI, confidence: high)
In general, the spatial patterns of observed trends in temperature are more consistent than for precipitation across the whole of South America (IPCC AR6_WGI, confidence: medium)
The most consistent evidence of positive rainfall trend occurs in the southern part of the La Plata basin (IPCC AR6_WGI, confidence: high)
Over the subtropical Andes, central Chile shows a robust signal of declining precipitation since 1970 (IPCC AR6_WGI, confidence: high)
Observational studies show that the dry-season length over southern Amazonia has increased significantly since 1979 (IPCC AR6_WGI, confidence: high)
In general, these changes are attributed mainly to decadal climate fluctuations (IPCC AR6_WGI, confidence: high)
Recent publications based on observational and modelling evidence assessed that anthropogenic forcing in CMIP5 models explains the overall warming (IPCC AR6_WGI, confidence: high)
In summary, analyses of historical temperature time series point strongly to an increased warming trend (IPCC AR6_WGI, confidence: high)
Annual rainfall has increased over South-Eastern South America and decreased in most tropical land regions, particularly in central Chile (IPCC AR6_WGI, confidence: high)
The number and strength of extreme events, such as extreme temperatures, droughts and floods, have already increased (IPCC AR6_WGI, confidence: medium)
Atlas.7.2.3 Assessment of Model Performance Since AR5 the number of publications on climate model performance and their projections in South America has increased, particularly for regional climate modelling studies (Giorgi et al., 2009; Boulanger et al., 2016; Ambrizzi et al., 2019) and the understanding of their strengths and weaknesses (IPCC AR6_WGI, confidence: high)
However, significant biases persist mainly at regional scales (IPCC AR6_WGI, confidence: high)
Most models show a dry bias over SES (Díaz and Vera, 2017; Barros and Doyle, 2018; Solman and Blázquez, 2019; Díaz et al., 2021) associated with an underestimation of the northern flow that brings water vapour into the region (IPCC AR6_WGI, confidence: medium)
The biases in seasonal precipitation, annual precipitation and climate extremes over several regions of South America were reduced, including the Amazon, central South America, Bolivia, eastern Argentina and Uruguay, in the CMIP5 models when compared to those of CMIP3 (IPCC AR6_WGI, confidence: medium)
Regional climate model (RCM) simulations over South America can reproduce the main features of temperature and precipitation in terms of both spatial distributions (Solman et al., 2013; Falco et al., 2019) and seasonal cycles over the different climate regimes, including the main SAmerM features (IPCC AR6_WGI, confidence: high)
However, RCMs showed systematic biases such as precipitation overestimations and temperature underestimations along the Andes throughout the year (IPCC AR6_WGI, confidence: high)
Temperature overestimation and precipitation underestimation over La Plata basin (in SES) are also RCM common biases, with the warm bias amplified for austral summer and the dry bias amplified for the rainy season (IPCC AR6_WGI, confidence: high)