Coupled climate and land use change effects on water availability for agriculture in the US midwest

Climate and land use/land cover (LULC) change pose significant challenges to U.S agriculture. Understanding the coupled impacts of these changes in the future on key hydrological processes is crucial for ensuring food and water security, conserving ecosystems, and promoting sustainable agriculture in a changing world. The agriculturally intensive Upper Mississippi River Basin (UMRB, 491 702 km ^2 ) of the Midwestern U.S. plays a critical role in U.S. agriculture, the regional economy, national and global food security, and environmental health. This study investigates the potential combined impacts of future climate and LULC on water availability and their implications for agricultural production in the UMRB. We found that the most notable reductions in soil moisture and streamflow and an increase in vapor pressure deficit are projected to occur during the growing season, which suggests that Midwest agriculture could face challenges in water availability during the critical phases of crop growth and development. Although the longer growing degree days could extend the length of the growing season, they could also lead to higher water demands for crops. The combined effects of climate and LULC change outweigh each single driver. The combined change can result in significant increases in water loss through ET (15.2% and 21.5% in 2071–2100 under the Shared Socioeconomic Pathway scenarios SSP245 (climate mitigation scenario with medium emissions) and SSP585 (a business-as-usual scenario that has high greenhouse gas emissions), respectively) and a decline in water yield (4.75% and 26.6% in 2071–2100 under SSP245 and SSP585, respectively). Policymakers and farmers may need to adapt to those future changes by prioritizing sustainable water management practices and adopting water-efficient technologies.