Impact of Climate Change on Cassava Yield in Guapimirim, State of Rio de Janeiro, Southeast Brazil

Abstract

Global warming has changed the climate in many parts of the world and affected ecosystems due to anthropogenic greenhouse gas (GHG) emissions that contribute to the rise in the surface temperature of the planet. Rising temperatures have important effects on agriculture, which accounts for one- third of Brazil's economy. This study assesses the impact of climate change over agriculture on cassava yield in Guapimirim city, State of Rio de Janeiro, Southeast Brazil. Bias corrected climate simulation performed from the nested model Eta-HadGEM2-ES was used to reproduce the climate data observed in the region and for climate projections under Representative Concentration Pathways (RCPs) 4.5 and 8.5 scenarios. Simulated rainfall and evapotranspiration for the period between 1961 and 1990 was compared to the observation period and, showed a correlation with R² = 0.99 and the Average Absolute Percentage Error was less than 5.0%. The effect of climate projections on water stress during crop development was estimated using the Thornthwaite-Mather (TM) soil water balance adapted for crops. Rainfall and actual evapotranspiration projections for the three thirty-year periods 2011-2040, 2041-2070, 2071-2100 served as the basis for the assessment of the Water Requirement Satisfaction Index (WRSI) and Yield Reduction (YR) for cassava crop. Projections show significant cassava yield losses around 8.6 and 9.7 ton ha-1, respectively, under RCPs 4.5 and 8.5. This approach allows exploratory analysis applied to support crop management decision-making and irrigation strategies for sustainable agriculture and to increase crop yield in the face of impacts of climate change.