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

==== 12.3.4.2 Exposure ====

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A large expansion in cropland area (soybean, corn and sugarcane) was observed in the past two decades in SAM, in response to increased local and global demand for biofuels and agricultural commodities ( ''high confidence'' ) ( [[#Lapola--2014|Lapola et al., 2014]] ; [[#Cohn--2016|Cohn et al., 2016]] ). Feedbacks to the climate system resulting from such land use changes are intricate. The clear-cutting of Amazon forest and Cerrado savannah in the region led to a local warming due to an increase in the energy balance and evapotranspiration ( [[#Malhado--2010|Malhado et al., 2010]] ); in contrast, the replacement of pasture by agriculture have led to a local cooling effect, due to changes in the surface albedo ( ''medium confidence: medium evidence, medium agreement'' ). Deforestation of the Amazon for pastures and soybean have decreased evapotranspiration during drought months and caused a localised lengthening of the dry season in northwestern SAM by 6.5 (± 2.5) d since 1979 ( ''medium confidence: medium evidence, medium agreement'' ) ( [[#Fu--2013|Fu et al., 2013]] ).

It is not surprising, therefore, that while SAM is the region in CSA that experienced the highest temperature increase in the last century, it is where most of the fire spots in the sub-continent are located, owing also to the prevalent use of fires in pasturelands ( ''medium confidence: medium evidence, high agreement'' ) ( [[#Bowman--2009|Bowman et al., 2009]] ). Recently, da Silva Junior et al. (2020) reported 6,708,350 and 6,188,606 fire foci in Cerrado and Amazonia, between 1999 and 2018, corresponding to 80% of the total observed in Brazil. The occurrence of extreme droughts has affected the carbon and water cycles in large areas of the Amazon rainforest ( ''high confidence'' ) ( [[#Lapola--2014|Lapola et al., 2014]] ; [[#Agudelo--2019|Agudelo et al., 2019]] ), in particular in its southern and eastern portions, where deforestation rates are higher. The loss of carbon in the Amazon region considering the combined effect of land use change in the southern portion of the region bordering Cerrado and Pantanal and global carbon emission scenarios can be as high as 38% at 4°C of warming, but limited to 8% if the Paris Agreement limit of 1.5°C is achieved ( ''medium confidence, medium evidence, high agreement'' ) ( [[#Burton--2021|Burton et al., 2021]] ), driving the region to be a net carbon source to the atmosphere ( [[#Gatti--2021|Gatti et al., 2021]] ). A recent extreme drought was estimated to affect the photosynthetic capacity of 400,000 km 2 of the forest ( [[#Anderson--2018b|Anderson et al., 2018b]] ); nevertheless, there are considerable uncertainties regarding the effects of CO 2 fertilisation in tropical forests and ecosystems ( ''medium confidence: medium evidence, high agreement'' ) ( [[#Sampaio--2021|Sampaio et al., 2021]] ). Extreme drought events increase forest vulnerability to fire, directly affecting the biodiversity and the forest structure and its plant species distribution ( ''high agreement'' ) ( [[#Brando--2014|Brando et al., 2014]] ). Production sectors are also exposed. SAM is pointed out as a region where agricultural production will be especially impacted by climate change, affecting the production of annual crops, fruits and livestock ( ''medium confidence: medium evidence, high agreement'' ) ( [[#Lapola--2014|Lapola et al., 2014]] ; [[#Zilli--2020|Zilli et al., 2020]] ).

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