Are historical trends in weather consistent with model predictions in the Central United States?

Abstract

Model projections predict increasing temperatures and precipitation change in many locations in the Central United States. To provide perspective on what these trends might bring relative to what has already happened, we compared historical temperature and precipitation change with what models from the Coupled Model Intercomparison Project (CMIP6) predict. The analysis focuses on regions represented by five long-term agroecosystem research sites along a latitudinal transect from Michigan to Iowa, Missouri, Oklahoma, and Mississippi. We analyzed trends in long-term records (≥50 years) of precipitation and temperature data at annual and monthly scales using indicators that characterize extreme and average temperature and rainfall amounts. Results show that temperatures have changed from 1900 to 2020, more for minimum (0.1°C-0.3°C decade^-1) than maximum (-0.1°C-0.2°C decade^-1), more for winter (-0.1°C-0.3°C decade^-1) than summer (-0.1°C-0.1°C decade^-1), and more often in the north than in the south. Except in Mississippi, annual precipitation has increased at rates of 25 mm decade^-1 or greater over 1950-2020, but monthly trends were inconsistent. Projected trends suggest continued temperature increases, highlighting the urgent need for research on management systems that are resilient to such increases.