Linking Biogeochemistry, Management and Economics: Climate Change Impacts on Soil C Dynamics in the Corn Belt.

Climate change is expected to significantly impact agricultural systems world-wide, including the cropland-dominated Corn Belt region of the US Midwest.  How climate change impacts will manifest themselves will depend on the direction, degree and variability of changes to temperature, precipitation and CO₂concentrations,  as well as human-responses through technology changes and adaption driven by economic and policy decisions.  In addition to direct impacts on crop production, climate change and CO₂increases will influence other soil and ecosystem processes, likely impacting GHG emissions from agriculture and the potential to achieve GHG mitigation through changes in management practices.  All of these processes interact with edaphic and landscape features that vary at fine scales.

Several previous studies have projected climate change impacts on agricultural production systems, globally and in the US.  Here we review previous findings, highlight key results and characterize changes over time in climate change impact assessments that have been reported.  In an ongoing project, our objectives are to forecast potential impacts on agricultural productivity, carbon and greenhouse gas balance, and economic returns at local to subregional scales for the Corn Belt region. To forecast a range of potential climate change impacts, we are using down-scaled (ca. 25X25 km) daily climate change scenarios from different IPCC emission/concentration scenarios and global circulation models developed for CMIP5, together with fine-scale management and soils data derived from the US National Resources Inventory (NRI) and ancillary data sets, to run the DayCent ecosystem simulation model for a variety of management systems and potential adaptive management in response to climate change.  The ecosystem simulations provide inputs to a spatially-distributed economic model, in order to represent feedbacks between biophysical responses of agroecosystems and economic and policy drivers, under climate change.  Details on our approach, major challenges and preliminary results will be presented.