Impact of Climate Change on the Sugar Cane Irrigation Water Demand in the Gramame River Watershed

Abstract

Climate change is a recurring theme as it impacts various sectors of society, including water resources, reflecting directly on human beings' activities. In this context, the objective of this study was to assess the impacts produced by climate change on the sugarcane water demands for irrigation in four municipalities within the Gramame River watershed. For this, the irrigation water demand was estimated from the calculation of the evapotranspiration of the sugarcane culture. The temperature data used in these estimates were obtained from the projections of three Regional Circulation Models: ICHEC-EC-EARTH-RCA4, MPI-ESM-LR-RCA4, and MPI-ESM-LR-REMO2009 taken from the Coordinated Regional Climate Downscaling (CORDEX). These demands were estimated for two intervals of years (2006-2037 and 2038-2069) and for two greenhouse gas emission scenarios, RCP 4.5 and RCP 8.5. The patterns of the temperature projections of the three models were evaluated and corrected in order to reduce uncertainties. The results indicate that the MPI-ESM-LR-REMO2009 model was the one that best represented the temperature in the current climate (1961-2005). Furthermore, the increase in temperature due to climate change affects irrigation water demand in the near future (2006-2037) with slight effects, and in the distant future (2038-2069) with stronger impacts.