Editing IPCC:AR6/WGII/Chapter-12 (section)

==== 12.3.4.1 Hazards ====

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Temperature extremes have ''likely'' increased in the intensity and frequency of hot extremes and decreased in the intensity and frequency of cold extremes ( [[#Donat--2013|Donat et al., 2013]] ; [[#Bitencourt--2016|Bitencourt et al., 2016]] ) (WGI AR6 Table 11.13, [[#Seneviratne--2021|Seneviratne et al., 2021]] ). In a vast transition zone between the Amazon and the Cerrado Biomes within the region, analysis of seasonal precipitation trends suggested that almost 90% of the observational sites showed a reduction in the length of the rainy season in the region ( [[#Debortoli--2015|Debortoli et al., 2015]] ), in the period 1971–2014 ( [[#Marengo--2018|Marengo et al., 2018]] ), confirming the growth in length of the dry season. Changes in the hydrological and precipitation regimes, characterised by a reduction in rainfall in southern Amazonia, in contrast to an increase in northwestern Amazonia, and overall increases in extreme precipitation and in the frequency of consecutive dry days have been reported by several authors ( [[#Fu--2013|Fu et al., 2013]] ; [[#Almeida--2017|Almeida et al., 2017]] ; [[#Marengo--2018|Marengo et al., 2018]] ; [[#Espinoza--2019a|Espinoza et al., 2019a]] ) with ''low confidence'' (WGI AR6 Table 11.14) ( [[#Seneviratne--2021|Seneviratne et al., 2021]] ) due to insufficient data coverage and trends in available data generally not significant.

The Amazon has been identified as one of the areas of persistent and emergent regional climate-change hotspots in response to various representative concentration pathways ( [[#Diffenbaugh--2012|Diffenbaugh and Giorgi, 2012]] ). In Bolivia, CMIP3/5 models projected an increase in temperature (2.5°C–5.9°C), with seasonal and regional differences. In the lowlands, both ensembles agreed on less rainfall (–19%) during drier months (June–August and September–November), with significant changes in interannual rainfall variability, but disagreed on changes during wetter months (January–March) ( [[#Seiler--2013|Seiler et al., 2013]] ). As a consequence of higher temperatures and reduced rainfall, an increased water deficit would be expected in the Brazilian Pantanal ( [[#Marengo--2016|Marengo et al., 2016]] ; [[#Bergier--2018|Bergier et al., 2018]] ; [[#Llopart--2020|Llopart et al., 2020]] ) with ''high confidence'' . The largest increases in warmer days and nights, and aridity, drought and significant increases in fire occurrence are calculated over the Amazon area ( [[#Huang--2016|Huang et al., 2016]] ). Over the entire region, by mid-century (RCP4.5) there is ''medium confidence'' of increases in river and pluvial floods, aridity and mean wind speed, and extreme heat, fire weather and drought are projected to increase with ''high confidence'' (WGI AR6 Table 12.6; [[#Ranasinghe--2021|Ranasinghe et al., 2021]] ).

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