Submitted to: Soil and Erosion and Global Change
Publication Type: Proceedings
Publication Acceptance Date: May 17, 2003
Publication Date: July 9, 2003
Citation: Nearing, M.A. 2003. Modeling climate change impacts on soil erosion: problems and solutions. Soil and Erosion and Global Change, Budapest Hungary 5-8 July 2003. Technical Abstract: Erosional impacts of climate change involve a highly complex interplay of processes. As the planet becomes warmer, the hydrologic cycle becomes more vigorous. Documented changes in annual precipitation and frequency of high intensity rainfall events show a statistical increase in both, on average, for the United States over the last century. Changes in climate and atmospheric CO2 levels will also impact biomass production, evapotranspiration, soil moisture balance, residue decomposition, soil surface sealing, and many other system factors. Thus, the assessment of climate change impacts on erosion and conservation is complex. Precipitation changes must be accounted for correctly, including correct representation of changes in rainfall amounts per storm event, rainfall intensities and durations, and the number of wet days. Temperature changes affect the proportion of precipitation that falls as snow and rain, as will seasonal changes in precipitation patterns. Atmospheric CO2 concentrations, moisture, and temperature affect biomass production levels, which in turn impact canopy and residue amounts, which in turn impact infiltration, runoff, and erosion rates. Changes in evapotranspiration rates and rainfall amounts impact soil moisture, which in turn impacts biomass production, infiltration rates, and ultimately erosion rates. Also, as the climate changes, so do farming practices. Climate changes are also likely to be accompanied by changes in farm management, as farmers adapt their management practices to the new climate. For instance, decreased crop yields may lead the farmer to plant a new crop, or farmers may change planting dates of maize to take advantage of increased warmth or to avoid high temperatures during silking. Farmers may also plant crop varieties of different maturity type, thus affecting the timing and duration of soil cover. All of these changes in management affect the impacts of climate change on erosion. For all of these reasons, a continuous simulation model must be used to assess climate change impacts on erosion and conservation. It is simply not possible to assess the complex interactions involved with changes in climatic impacts using a single storm erosion or watershed model. This presentation will present details of the problems associated with modeling climate change impacts on erosion, and examples of methods for approaching this highly complex problem in a process-integrated manner.