Editing IPCC:AR6/WGII/Cross-Chapter-Paper-3 (section)

==== CCP3.2.1.1 Temperature and Rainfall ====

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Significant warming has occurred across drylands globally ( [[#IPCC--2021|IPCC, 2021]] ). Surface warming (1920–2015) of 1.2 ° C–1.3 ° C in global drylands has exceeded the 0.8 ° C–1.0 ° C warming over humid lands ( [[#Huang--2017|Huang et al., 2017]] ). As measured by the AI, this has expanded the area of drylands by ~4% from 1948–2004 ( [[#Ji--2015|Ji et al., 2015]] ; [[#Spinoni--2015|Spinoni et al., 2015]] ; [[#Huang--2016|Huang et al., 2016]] ). However, as mentioned in Figure CCP3.1, the AI has various limitations in assessing drylands expansion. Increases in potential evapotranspiration have exceeded increases in precipitation in the last half of the period 1901–2017 ( [[#Pan--2021|Pan et al., 2021]] ). Observations from the Sahel demonstrated that temperature seasonality changes differ from rainfall seasonality changes (Guichard et al., 2015), and there has been an increase in surface water and groundwater recharge in the Sahel since the 1980s, referred to as ‘the Sahel paradox’ ( [[#Favreau--2009|Favreau et al., 2009]] ; [[#Gardelle--2010|Gardelle et al., 2010]] ; [[#Descroix--2013|Descroix et al., 2013]] ; [[#Wendling--2019|Wendling et al., 2019]] ). Research from the USA suggests that historical soil moisture levels can contribute to such variability ( [[#Heisler-White--2009|Heisler-White et al., 2009]] ). Studies from the Middle East show rising temperatures and declining rainfall trends ( [[#ESCWA--2017|ESCWA, 2017]] ), with most decreasing aridity trends in north Sudan and most increasing aridity trends in eastern Arabia over the period 1948–2018 ( [[#Sahour--2020|Sahour et al., 2020]] ).

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