Future Projections (2015-2100) of Daily Temperature Range (DTR) in South America: Multiregional Analysis Based on CMIP6 Models

This study investigates future projections of the DTR over the South American area using CMIP6 modeled data on the maximum (Tmax) and minimum (Tmin) temperatures under two socioeconomic scenarios, SSP2-4.5 (low greenhouse gas emissions) and SSP5-8.5 (high emissions). The continental region was divided into 10 subregions, with the boundaries drawn based on their climatic characteristics, and for each one, ensembles of the five best-performing models were generated. This selection of models is based on a comparison of their historical series with an observed reference series obtained from the Climatic Research Unit (CRU)'s time series (TS). The statistical analysis, which used the modified Mann–Kendall test and the Theil–Sen slope estimator, reveals that Tmin and Tmax show an increasing trend over time. However, the increase in Tmin is more pronounced, resulting in a reduction in the DTR in most subregions. For example, it is estimated that in SSP2-4.5, the DTR will decrease by approximately –0.71 °C between the periods 2015–2025 and 2090–2100, while in SSP5-8.5, this reduction could reach approximately –1.04 °C. Some areas, such as the south of northeast Brazil, southeast Brazil, south Brazil, and Uruguay, show opposite patterns, with an increase in the DTR. These results reinforce the influence of anthropogenic factors in modulating the DTR, and the findings provide support for the development of policies to adapt to and mitigate the impacts of climate change on the South America continent.