Editing IPCC:AR6/WGI/Chapter-Atlas (section)

===== Atlas.5.5.1.2 Findings From Previous IPCC Assessments =====

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The IPCC AR5 established it is ''very likely'' that temperatures will continue to increase over WCA in all seasons whilst projections of decreased annual mean precipitation had ''medium confidence'' due to ''medium agreement'' resulting from model-dependent sub-regional and seasonal changes ( [[#Christensen--2013|Christensen et al., 2013]] ). The AR5 also concluded that for a better understanding of the climate of the region, results of high-resolution regional climate models also need to be assessed and CMIP5 models generally had difficulties simulating the mean temperature and precipitation climatology for South West Asia. This is partly related to the poor spatial resolution of the models not resolving the complex mountainous terrain and the influence of different drivers of the European, Asian and African climates. However, observational data scarcity and issues related to the comparison of observations with coarse-resolution models added to the uncertainty and remained poorly analysed in peer-reviewed literature on climate model performance ( [[#Christensen--2013|Christensen et al., 2013]] ).

The SR1.5 stated that even for 1.5°C and 2°C of global warming, South West Asia is among the regions with the strongest projected increase in hot extremes with more urban populations exposed to severe droughts in West Asia, while an increase of heavy precipitation events is projected in mountainous regions of Central Asia ( [[#Hoegh-Guldberg--2018|Hoegh-Guldberg et al., 2018]] ; [[#IPCC--2018c|IPCC, 2018c]] ). Higher temperatures with less precipitation will ''likely'' result in higher risks of desertification, wildfires and dust storms exacerbated by land-use and land-cover changes in the region with consequent effects on human health. Further drying of the Aral Sea in Central Asia will ''likely'' have negative effects on the regional microclimate, adding to the growing wind erosion in adjacent deltaic areas and deserts that is already resulting in a reduction of the vegetation productivity including croplands. There is also a projected increase of precipitation intensity in the Arabian Peninsula which is ''likely'' to lead to higher soil erosion particularly in winter and spring due to floods ( [[#Mirzabaev--2019|Mirzabaev et al., 2019]] ). 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 ( ''high confidence'' ). A very strong interannual and decadal variability, as well as scarce in situ records for mountain snow cover, have prevented a quantification of recent trends in High Mountain Asia (Hock et al., 2019b).

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