Assessing sugarcane expansion to ethanol production under climate change scenarios in Paranaíba river basin – Brazil

Abstract

Agroclimatic aptitude can provide information on regions with less impact to the environment for sugarcane growth to ethanol production. In this study, agroclimatic aptitude maps are generated for the region encompassing the Paranaíba river basin in central-western Brazil, which has presented suitable conditions for sugarcane expansion. Considering a rainfed framework, the hydrological requirements were estimated using meteorological station data; numerical integrations of climate change projections, from the Geophysical Fluid Dynamics Laboratory's Earth System Models under two climate change scenarios; and the crop model, CROPWAT 8.0, from the Food and Agriculture Organization of the United Nations. The resulting agroclimatic aptitude maps exhibit areas of sugarcane vulnerability to climate change, as well as potential regions for its expansion. None of the performed analyses indicate the increase in temperature as a limiting factor for sugarcane production in that region. Considering thermal and hydric aptitudes, the water deficit is the only limiting factor in the study area, therefore sugarcane production would require irrigation. This study presents the southwestern region of the river basin as more suitable to the expansion of sugarcane, because the lower risk of water deficit, under different climate paths with distinctive El Niño Southern Oscillation variability conditions. Additionally, the southwestern part of the Paranaíba river basin has fewer environmental conservation units, as well as a vast pastureland. Cattle herd can be reallocated toward degraded pasturelands, which in turn can be recovered. Therefore, sugarcane expansion to the southwestern region of the Paranaíba river basin would affect less the environment.