Submitted to: Global Climate Change Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/13/2005
Publication Date: 11/16/2005
Citation: Del Grosso, S.J., Ogle, S., Follett, R.F., Parton, W.J., Paustian, K. 2005. Using ecosystem models to inventory and mitigate environmental impacts of agriculture. Global Climate Change Conference Proceedings. (Poster presentation during meeting.) Interpretive Summary:
Technical Abstract: As a provider of climate change information, the presenter will discuss how ecosystem models can be used to asses and mitigate some environmental impacts of agriculture. Agriculture is the source of ~20% of global radiative forcing from the most important long-lived greenhouse gases (GHG’s): carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Agriculture is a relatively small source of CO2, but is responsible for ~50% and ~70%, respectively, of the anthropogenic emissions of CH4 and N2O. Agriculture is also the primary contributor of eutrophication of aquatic systems from nutrients that are runoff or leached from cropped fields into water ways. Thus, there exist potential to mitigate the impacts of agriculture on GHG emissions and water quality. The authors have developed inventories to estimate national emissions under present conditions which can also be used to identify areas that have large mitigation potential. For example, carbon (C) sequestration in agricultural soils has been suggested as a way to reduce national GHG emissions but inventories generated by the authors show that CO2 emissions from histosol (organic soil) cropping nullifies >50% of the C sequestered in non-histosol cropped soils even though histosols occupy <1% of total US cropped land. Because it is not feasible to measure emissions at regional and larger scales, national inventories employ models. The authors are using the CENTURY and DAYCENT ecosystem models to estimate emissions from major cropping systems for the US national inventory. Models used to establish emissions under current management practices can also be used to compare alternative management scenarios intended to reduce emissions. For example, projected crop yield, soil C, and GHG outputs from CENTURY and DAYCENT have been linked with economic models to evaluate the costs/benefits of competing management strategies at the global scale. Although the use of ecosystem models in GHG inventories has increased confidence in emission estimates, there remains considerable uncertainty regarding both the estimates of GHG emissions under typical management practices and the extent to which these can be reduced under alternative management scenarios. Inventories can be improved and uncertainties reduced by increasing resources to collect field data for model/data comparisons and to acquire more refined activity data needed for model inputs.