Climate Change Impacts on Crop Production in High Latitude Regions: A Case Study of the Upper Great Lakes Region of the United States

Future climate change is expected to substantially affect agricultural production worldwide. Globally, adverse impacts on agriculture are anticipated for low latitude regions; whereas, agriculture in high latitude regions may benefit from climate change. However, this generalization is complicated by spatial variations in projections of future climate and other environmental factors important for agricultural production, such as soil fertility. The major goal of this study is to evaluate the potential impacts of projected future climate change on crop production for high latitude regions. This research focuses on the impacts of future climate change on county-level corn and soybean production in the Upper Great Lakes Region (UGLR) of the United States, encompassing the states of Michigan, Wisconsin and Minnesota. This region, located between approximately 41.5°N-49.5°N, serves as an excellent case study for evaluating potential latitudinal shifts in favorable growing regions. The CERES-Maize and CROPGRO-Soybean models included in the Decision Support System for Agrotechnology Transfer (DSSAT) were employed to simulate county-level crop production for current (1971-2000) and future (2041-2070) time slices. Regionalization and spatial analysis methods were employed to handle the different spatial scales of the input variables. Climate change projections were derived from an ensemble of simulations from regional climate models run under the SRES A2 emission scenario and available from the North America Regional Climate Change Assessment Program (NARCCAP). Two different concentrations of atmospheric carbon dioxide (490 and 635 ppm), corresponding to the beginning (2041) and end (2070) year of the future period, were used to assess the sensitivity of crop yield to carbon dioxide levels.

The analysis suggests that future climate change will alter planting date, time to maturity, seasonal evapotranspiration (ET), and grain yield of corn and soybean production in the UGLR. For corn production, the southern areas, i.e., the current major production areas, may experience earlier planting dates by mid century, whereas slightly later planting dates may occur in the northern areas. For soybean production, a west-east gradient of changing planting dates is suggested, with earlier planting dates in the western UGLR and later planting dates in the eastern UGLR. Warmer temperatures are expected to reduce time to maturity for both crops in the majority of counties in the UGLR. Seasonal ET for corn production generally is expected to decrease in the southern UGLR and increase in the northern UGLR. For soybean production, seasonal ET is projected to change only slightly by the mid century. More favorable growing conditions by the mid century will benefit the northern UGLR where some areas may produce relatively high corn and soybean yields especially under elevated carbon dioxide concentrations. Despite a potential small reduction in crop yields, crop production in the southern UGLR is expected to remain large, partially due to the positive impact of elevated carbon dioxide concentrations. Specifically for corn, we also found that a long season cultivar is likely to benefit more from climate change than medium and short season cultivars. Interpretation of future impacts varied somewhat depending upon the NARCCAP simulations employed to derive the future climate projections.