Potential Impacts of Droughts on Crop Productivity in the United States over 21st Century

Abstract:

Crop productivity in the US plays a critical role in ensuring global food security. However, US agricultural ecosystems have experienced frequent and intensive droughts over past decades including extreme droughts in recent two years, which led to large reductions in crop productivity and have been posing unprecedented challenges to US agricultural land. Therefore, there is an increasing concern about how future drought condition would be and how agricultural ecosystems would respond to future droughts. Here, we use the process-based ecosystem model DLEM-Ag (the agricultural module of the Dynamic Land Ecosystem Model) driven by future climate change scenarios, new-released RCPs data from the IPCC Fifth Assessment Report, to examine the impacts of future climate change/extremes on crop productivity and yield in the US during 2015-2099. The preliminary results show that more pervasive global-change-type droughts over the 21st century would be projected to occur in large areas of cropland in the Mississippi River basin and the southeastern US, which would significantly cause adverse impacts on crop productivity, particularly under high emission scenario RCP8.5. Our study implies that the restrictions on anthropogenic greenhouse gases emissions would benefit crop productivity in US.