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

=== Heavy Precipitation and Pluvial Floods ===

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'''The frequency and intensity of heavy precipitation events have''' ''likely'' '''increased at the global scale over a majority of land regions with good observational coverage.''' '''Heavy precipitation has''' ''likely'' '''increased on the continental scale over three continents: North America, Europe, and Asia.''' Regional increases in the frequency and/or intensity of heavy precipitation have been observed with at least ''medium confidence'' for nearly half of AR6 regions, including WSAF, ESAF, WSB, SAS, ESB, RFE, WCA, ECA, TIB, EAS, SEA, NAU, NEU, EEU, GIC, WCE, SES, CNA, and ENA. {11.4, 11.9}

'''Human influence, in particular greenhouse gas emissions, is''' ''likely'' '''the main driver of the observed global-scale intensification of heavy precipitation over land regions.''' It is ''likely'' that human-induced climate change has contributed to the observed intensification of heavy precipitation at the continental scale in North America, Europe and Asia. Evidence of a human influence on heavy precipitation has emerged in some regions ( ''high confidence'' ). {11.4, 11.9, Table 11.1}

'''Heavy precipitation will generally become more frequent and more intense with additional global warming. At a global warming level of 4°C relative to the pre-industrial level, very rare (e.g., one in 10 or more years) heavy precipitation events would become more frequent and more intense than in the recent past, on the global scale''' ( ''virtually certain'' ''') and in all continents and AR6 regions. The increase in frequency and intensity is''' ''extremely likely'' '''for most continents and''' ''very likely'' '''for most AR6 regions.''' At the global scale, the intensification of heavy precipitation will follow the rate of increase in the maximum amount of moisture that the atmosphere can hold as it warms ( ''high confidence'' ), of about 7% per 1°C of global warming. The increase in the frequency of heavy precipitation events will be non-linear with more warming and will be higher for rarer events ( ''high confidence'' ), with a ''likely'' doubling and tripling in the frequency of 10-year and 50-year events, respectively, compared to the recent past at 4°C of global warming. Increases in the intensity of extreme precipitation at regional scales will vary, depending on the amount of regional warming, changes in atmospheric circulation and storm dynamics ( ''high confidence'' ). {11.4, Box 11.1}

'''The projected increase in the intensity of extreme precipitation translates to an increase in the frequency and magnitude of pluvial floods – surface water and flash floods –''' ( ''high confidence'' '''), as pluvial flooding results from precipitation intensity exceeding the capacity of natural and artificial drainage''' '''systems.''' {11.4}

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