Editing IPCC:AR6/WGI/Chapter-11 (section)

==== 11.6.2.2 Atmospheric Evaporative Demand ====

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In several regions, AED increases have intensified recent drought events ( [[#Williams--2014|Williams et al., 2014]] , 2020; [[#Seager--2015b|Seager et al., 2015b]] ; [[#Basara--2019|Basara et al., 2019]] ; [[#García-Herrera--2019|García-Herrera et al., 2019]] ), enhanced vegetation stress ( [[#Allen--2015|Allen et al., 2015]] ; [[#Sanginés%20de%20Cárcer--2018|Sanginés de Cárcer et al., 2018]] ; [[#Yuan--2019|Yuan et al., 2019]] ), or contributed to the depletion of soil moisture or runoff through enhanced ET ( ''high confidence'' ) ( [[#Teuling--2013|Teuling et al., 2013]] ; [[#Padrón--2020|Padrón et al., 2020]] ). Trends in pan evaporation measurements and Penman-Monteith AED estimates provide an indication of possible trends in the influence of AED on drought. Given the observed global temperature increases (Sections 2.3.1.1 and 11.3) and dominant decrease in relative humidity over land areas ( [[#Simmons--2010|Simmons et al., 2010]] ; [[#Willett--2014|Willett et al., 2014]] ), VPD has increased globally ( [[#Barkhordarian--2019|Barkhordarian et al., 2019]] ; [[#Yuan--2019|Yuan et al., 2019]] ). Pan evaporation has increased as a consequence of VPD changes in several AR6 regions, such as East Asia ( [[#Li--2013|Li et al., 2013]] ; Z. [[#Sun--2018|Sun et al., 2018]] ; M.-Z. [[#Yang--2018|]] [[#Yang--2018|]] [[#Yang--2018|]] [[#Yang--2018|]] [[#Yang--2018|Yang et al., 2018]] ), Western and Central Europe ( [[#Mozny--2020|Mozny et al., 2020]] ), the Mediterranean, ( [[#Azorin-Molina--2015|Azorin-Molina et al., 2015]] ) and Central and Southern Australia ( [[#Stephens--2018|Stephens et al., 2018]] ). Nevertheless, there is an important regional variability in observed trends, and in other AR6 regions pan evaporation has decreased – for example, in North Central America ( [[#Breña-Naranjo--2017|Breña-Naranjo et al., 2017]] ) and in the Tibetan Plateau ( [[#Zhang--2018|]] [[#Zhang--2018|]] [[#Zhang--2018|C. Zhang et al., 2018]] )). Physical models also show an important regional diversity, with an increase in New Zealand ( [[#Salinger--2014|Salinger and Porteous, 2014]] ) and the Mediterranean ( [[#Gocic--2014|Gocic and Trajkovic, 2014]] ; [[#Azorin-Molina--2015|Azorin-Molina et al., 2015]] ; [[#Piticar--2016|Piticar et al., 2016]] ), a decrease in South Asia ( [[#Jhajharia--2015|Jhajharia et al., 2015]] ), and strong spatial variability in North America ( [[#Seager--2015b|Seager et al., 2015b]] ). This variability is driven by the role of other meteorological variables affecting AED. Changes in solar radiation as a consequence of solar dimming and brightening may affect trends ( [[IPCC:Wg1:Chapter:Chapter-7#7.2.2.2|Section 7.2.2.2]] ; [[#Kambezidis--2012|Kambezidis et al., 2012]] ; [[#Wang--2014|Wang and Yang, 2014]] ; [[#Sanchez-Lorenzo--2015|Sanchez-Lorenzo et al., 2015]] ). Wind speed is also relevant ( [[#McVicar--2012b|McVicar et al., 2012b]] ), and studies suggest a reduction of the wind speed in some regions (Z. [[#Zhang--2019|]] [[#Zhang--2019|]] [[#Zhang--2019|]] [[#Zhang--2019|Zhang et al., 2019]] b) that could compensate the role of the VPD increase. Nevertheless, the VPD trend seems to dominate the overall AED trends, compared to the effects of trends in wind speed and solar radiation ( [[#Wang--2012|Wang et al., 2012]] ; [[#Park%20Williams--2017|Park Williams et al., 2017]] ; [[#Vicente-Serrano--2020a|Vicente-Serrano et al., 2020a]] ).

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