Editing IPCC:AR6/WGI/Chapter-7 (section)

====== Land cloud feedback ======

Intensification of the global hydrological cycle is a robust feature of global warming, but at the same time, many land areas in the subtropics will experience drying at the surface and in the atmosphere ( [[IPCC:Wg1:Chapter:Chapter-8#8.2.2|Section 8.2.2]] ). This occurs due to limited water availability in these regions, where the cloudiness is consequently expected to decrease. Reduction in clouds over land is consistently identified in the CMIP5 models and also in a GCM with explicit convection ( [[#Bretherton--2014|Bretherton et al., 2014]] ; [[#Kamae--2016a|Kamae et al., 2016a]] ). Because low-clouds make up the majority of subtropical land clouds, this reduced amount of low-clouds reflects less solar radiation and leads to a positive feedback similar to the marine low-clouds. The mean estimate of the global land cloud feedback in CMIP5 models is smaller than the marine low-cloud feedback, 0.08 ± 0.08 W m <sup>–2</sup> °C <sup>–1</sup> ( [[#Zelinka--2016|Zelinka et al., 2016]] ). These values are nearly unchanged in CMIP6 ( [[#Zelinka--2020|Zelinka et al., 2020]] ). However, ESMs still have considerable biases in the climatological temperature and cloud fraction over land, and the magnitude of this feedback has not yet been supported by observational evidence. Therefore, the feedback due to decreasing land clouds is assessed to be 0.08 ± 0.08 W m <sup>–2</sup> °C <sup>–1</sup> (one standard deviation) with ''low confidence'' .

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