Biogeochemical and biophysical climate regulation services from converting native grassland to bioenergy production in the US Midwest

Abstract:

Land use conversion to bioenergy crops production not only alters biogeochemical cycles, but also modifies surface biophysics, such as albedo and and leaf area. These biophysical perturbations subsequently change radiation budget at land surface and land-atmosphere exchange in water and energy, and ultimately influence local/regional climate. Here, we combine long-term in situ field measurements, remote sensing observations, and regional earth system modeling to improve our understanding of changes in biophysical climate regulation services from converting native grassland to perennial bioenergy crops. In the US Midwest, albedo change as a result of cultivating native grassland for cellulosic bioenergy feedstocks could enhance the net greenhouse gases (GHGs) mitigation benefit of cellulosic bioenergy production (116.5 MgCO₂ ha^-1) by 20% over a time horizon of 50 years. With an integrated climate-agroecosystem model, parameterized with in situ and remote sensing data, we further demonstrate that cultivating native grassland may result in noticeable difference in simulated regional climate (e.g. precipitation, temperature, and radiation budget), highlighting the importance of additionally including biophysical climate services in evaluating land-based climate mitigation activities, such as bioenergy production.