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

==== Atlas.7.2.4 Assessment and Synthesis of Projections ====

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It is ''very likely'' that annual mean temperature will increase over South America, with a wide range of projected changes of 1.0°C–6.0°C by the end of the 21st century (from RCP2.6/SSP1-2.6 to RCP8.5/SSP5-8.5 emissions, Figure Atlas.22). Overall, GCMs project higher temperature change than RCMs in austral summer and winter over all sub-regions and in winter mainly over the central part of the continent (Interactive Atlas; [[#Coppola--2014|Coppola et al., 2014]] ; [[#Llopart--2021|Llopart et al., 2021]] ; [[#Teichmann--2021|Teichmann et al., 2021]] ). The largest warmings over the South American continent are projected for the Amazon basin (SAM and NSA) and the central Andes range (southern SAM, northern SWS and south-eastern NWS; Figure Atlas.22), especially during the dry and dry-to-wet transition seasons (austral winter and spring) ( ''high confidence'' ) ( [[#Blázquez--2013a|Blázquez and Nuñez, 2013a]] ; [[#Coppola--2014|Coppola et al., 2014]] ; [[#Pabón-Caicedo--2020|Pabón-Caicedo et al., 2020]] ; [[#Teichmann--2021|Teichmann et al., 2021]] ).

Using warming levels (Figure Atlas.22), the temperature is projected to increase at or above the level of global warming in all regions apart from SSA with additional warming (compared to a 1995–2014 baseline) of over 4°C for the 4°C warming level in NSA and SAM. Changes for other warming levels, sub-regions and emissions pathways are shown in Figure Atlas.22 and can be explored with the Interactive Atlas.

In general, models show a wide regional range in the direction and the magnitude of mean precipitation change in many South American regions, with large significant increases and decreases (Figure Atlas.22 and the Interactive Atlas). In the medium and long term, under the high-emissions scenario, the CMIP5 multi-model ensemble projected an increase in precipitation (generally greater than 10%) in SES and NWS, and a decrease (less than 10%) in NSA across seasons ( ''high confidence'' , ''robust evidence'' ) ( [[#Solman--2013|Solman, 2013]] ; [[#Chou--2014|Chou et al., 2014]] ; [[#Coppola--2014|Coppola et al., 2014]] ; [[#Llopart--2014|Llopart et al., 2014]] , 2021; [[#Reboita--2014|Reboita et al., 2014]] , 2021; [[#Sánchez--2015|Sánchez et al., 2015]] ; [[#Menéndez--2016|Menéndez et al., 2016]] ; [[#Ruscica--2016|Ruscica et al., 2016]] ; [[#Bozkurt--2018a|Bozkurt et al., 2018a]] ; [[#Zaninelli--2019|Zaninelli et al., 2019]] ). Also, in parts of SWS, annual precipitation is projected to decrease (up to 30%) by the late 21st century ( [[#Souvignet--2010|Souvignet et al., 2010]] ; [[#Palomino-Lemus--2017|Palomino-Lemus et al., 2017]] , 2018; [[#Bozkurt--2018a|Bozkurt et al., 2018a]] ). Under high RCPs, the CMIP5 ensemble projects that all Brazilian regions will experience more rainfall variability in the future, so drier dry periods and wetter wet periods on daily, weekly, monthly and seasonal time scales, despite the future changes in mean rainfall being currently uncertain ( ''medium confidence'' ) ( [[#Alves--2021|Alves et al., 2021]] ). Regarding the SAmerM, it is ''very likely'' that the monsoon will experience changes in its life cycle by the end of the 21st century for both RCP4.5 and RCP8.5 emissions and, in particular, delayed onset. However there is ''low agreement'' on the projected changes in terms of extreme and total precipitation of the monsoon season in South America ( [[#Llopart--2014|Llopart et al., 2014]] ; [[#Ashfaq--2021|Ashfaq et al., 2021]] ). Changes in the SAmerM are assessed in [[IPCC:Wg1:Chapter:Chapter-8#8.3.2.4.5|Section 8.3.2.4.5]] .

Projected changes in seasonal precipitation and their uncertainties generally agree with the annual changes, particularly for the decreases in SWS (Figure Atlas.22). DJF precipitation changes in NSA and SAM are largely uncertain, with weak agreements in the projections, particularly for CMIP5 and CMIP6 ensembles, which project almost no change, and decreasing precipitation for NSA and a narrow range from slight increases to no change respectively for SAM.

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