A Worrying Future for River Flows in the Brazilian Cerrado Provoked by Land Use and Climate Changes

In this study, we assessed the impacts of land use and climate changes on the river flows of 81 watersheds within the Cerrado biome, Brazil, based on a comprehensive analysis of field and secondary data acquired between 1985 and 2018. Complementarily, we projected a future deforestation and climate scenario up to 2050 and predicted their impacts on surface water in the study area. We observed that direct impacts by large-scale deforestation oriented to the production of irrigated agricultural commodities have more significantly impacted river flows than climate changes. We estimated an average decrease of 8.7% and 6.7% in the streamflow due to deforestation and climate changes, respectively. Most of the observed changes (56.7%) were due to land use and land cover changes and occurred in recent decades. Climate and land use and land cover changes combined were responsible for a total surface water reduction of -19,718 m(3)/s within the Cerrado watersheds. By assuming the current deforestation rates, we predicted a total water reduction of 23,653 m(3)/s by 2050, equivalent to a decrease of 33.9% of the river flows in the study region. It will cause severe streamflow discontinuity in many rivers and strongly affect agricultural, electric power production, biodiversity, and water supply, especially during dry seasons in that region.

Automated summary

In this study, the impacts of land use and climate changes on river flows in the Cerrado biome, Brazil, were assessed using field and secondary data from 1985 to 2018. Future deforestation and climate scenarios up to 2050 were projected, and their impacts on surface water were predicted. The study found that large-scale deforestation for irrigated agricultural production had a more significant impact on river flows than climate changes. It was estimated that deforestation and climate changes led to a decrease of 8.7% and 6.7% in streamflow, respectively. The combined effects of land use and land cover changes and climate changes resulted in a total reduction of -19,718 m(3)/s in surface water within the Cerrado watersheds. By assuming current deforestation rates, it was predicted that there would be a total water reduction of 23,653 m(3)/s by 2050, equivalent to a decrease of 33.9% in river flows in the region.