Assessing future projections of meteorological droughts across Brazilian catchments

Código

I-EBHE0021

Autores

André Simões Ballarin, Mijael Rodrigo Vargas Godoy, Masoud Zaerpour, Jamil Alexandre Ayach Anache, Edson Cezar Wendland, Simon Michael Papalexiou

Tema

WG 2.1: Drought in the Anthropocene

Resumo

Droughts pose significant challenges to both natural and human systems, and there is growing evidence that they might become more severe as a result of global warming. Despite the importance of drought assessments for enhancing society's preparedness, studies on droughts are geographically disparate. Here, using bias-corrected CMIP6 projections and a standard precipitation-evaporation index?based approach, we assessed future projections of drought dynamics across 735 Brazilian catchments. Besides quantifying the anticipated changes in drought properties, we examined their implications for society by assessing the projected changes under both land use and water demand perspectives. Furthermore, we introduce a novel framework that elucidates the interplay between drought patterns and long- and short-term precipitation and potential evapotranspiration conditions. Our findings reveal a consensus among CMIP6 models, indicating an overall increase in both the frequency and severity of drought events across Brazilian territory. Particularly, under the pessimistic SSP5-8.5 scenario, a substantial portion of Brazilian croplands and pastures are expected to witness an increase of over 30% in drought severity by the end of the century. From the water demand perspective, our findings suggested that most catchments expected to experience heightened drought events are also projected to face escalated water consumption, which will likely aggravate future water security conditions. The investigation of the interplay between changes in meteorological conditions and drought properties suggested a potential linkage between intensified future droughts and elevated long-term average potential evapotranspiration (PET) and precipitation (P) temporal variability, but not necessarily total P. Notably, nearly half of the Brazilian catchments anticipated to undergo exacerbated droughts are expected to show enhanced P in the future. We posit that this study holds promise for bolstering Brazilian water resilience and enriching our comprehension of drought dynamics in an uncertain climate future.