|Pruski, F - BRAZIL|
Submitted to: Water Resources Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2002
Publication Date: N/A
Interpretive Summary: Global climate change is occurring now. Historical weather records over this last century show that precipitation is increasing both in terms of the number of days we have rain and the intensities of rain. Statistical analyses of the records have indicated that there is a less than one in a thousand chance that the changes in these patterns of precipitation could have occurred under a stable climate. We expect in the future that parts of the country will become wetter, and parts will become drier. We also have good scientific reason to believe that temperature will increase in the US during next century as well. As rainfall, temperature, and atmospheric carbon dioxide levels change, so will soil erosion. In this study we used computer simulation models to look at how changes in precipitation, temperature, and carbon dioxide levels might affect erosion rates in the United States. Our results indicate that changes in both runoff and erosion may be significant, and overall will increase. Changes in runoff can have major impacts on flooding, which has been a serious problem in recent years in many parts of the U.S. Changes in soil erosion may mean that we will need changes in our conservation strategies. The impact of this research will be better and more targeted conservation strategies for the future, which will ultimately result in a better soil resource base for growing food in this country.
Technical Abstract: Climate in the United States is expected to change during the next century, and soil erosion rates may be expected to change in response to changes in climate for a variety of reasons. This study was undertaken to investigate potential impacts of climate change on soil erosion by water. Erosion at eight locations in the United States were modeled using the Water Erosion Prediction Project (WEPP) model modified to account for the effects of atmospheric CO2 concentrations on plant growth. Simulated climate data from the Hadley Centre's HadCM3 Global Circulation Model were used. The results indicated an extremely complex set of interactions between the several factors that affect the erosion process. Direct effects of rainfall increases and decreases to runoff and erosion increases and decreases, respectively, were observed, but were often not dominant. One of the key factors of change in the system was the biomass production. Changes in soil moisture, atmospheric CO2 concentration, temperature, and solar radiation each impacted the biomass production at differing levels at the eight different sites. Different types of changes occurring at different periods of the year also complicated the response of the system. Overall results suggest that where precipitation increases are significant, erosion can be expected to increase. Where precipitation decreases occur the results may be more complex due largely to interactions of plant biomass, runoff, and erosion, and either increases or decreases in overall erosion may be expected.