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Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/15/2004 Publication Date: 10/30/2004 Citation: Zhang, X.J. 2004. Spatial sensitivity of predicted soil erosion and runoff to climate change at regional scales. Journal of Soil and Water Conservation. 61(2):58-64. Interpretive Summary: Knowledge of the potential impacts of climate changes on soil erosion is critical to natural resources conservation planning. The objectives of this paper were to evaluate spatial sensitivity of predicted soil loss and runoff to climate changes at large scales, and to simulate the 'regional' impacts of climate changes on soil erosion and runoff at Chickasha, Oklahoma. Relative climate changes at three spatial scales between the two periods of 1950-99 and 2070-99, projected using the Hadley Centre's general circulation model (HadCM3) under the A2a, B2a, and GGa1 emissions scenarios (representing high, low, and intermediate emissions, respectively), were used to generate changed climates for Chickasha. The Water Erosion Prediction Project (WEPP) model was run for each climate scenario at three spatial scales in three tillage systems. The HadCM3 predicted a general decrease in precipitation and an increase in the east-west precipitation gradient on the Southern Great Plains over the century. The decrease in precipitation resulted in general decreases in predicted runoff and soil loss at Chickasha. Percent changes, comparing to the present climate, ranged from -33 to -3% for runoff and from -33 to 0% for soil loss. Results indicated that variability of predicted runoff and soil loss at Chickasha under relative climate changes at three spatial scales was in the same magnitude as variability between climate change scenarios. This work suggests that spatial scale be considered in the impact assessments, and further provides a pragmatic means for modelers and conservation professionals to assess the potential impacts of climate change on natural resources. Technical Abstract: Impacts of climate change on natural resources need to be assessed in a range of geography and agricultural systems for better conservation planning. The objectives of this paper were to evaluate spatial sensitivity of predicted soil loss and runoff to climate changes at large scales, and to simulate the 'regional' impacts of climate changes on soil erosion and runoff at Chickasha, Oklahoma. Relative climate changes at three spatial scales between the two periods of 1950-99 and 2070-99, projected using HadCM3 under the A2a, B2a, and GGa1 emission scenarios, were used to generate changed climates for Chickasha, Oklahoma. The Water Erosion Prediction Project (WEPP) model was run for each climate scenario at three spatial scales in three tillage systems. The HadCM3 predicted a general decrease in precipitation and an increase in the east-west precipitation gradient on the Southern Great Plains over the century. The decrease in precipitation resulted in general decreases in predicted runoff and soil loss at Chickasha. Percent changes, comparing to the present climate, ranged from -33 to -3% for runoff and from -33 to 0% for soil loss. Results indicated that variability of predicted runoff and soil loss at Chickasha under relative climate changes at three spatial scales was in the same magnitude as variability between climate change scenarios. This finding suggests that spatial scale be considered in the impact assessments. Assessing impacts at multiple spatial scales not only yields a range of possible responses but also information on their potential variability. |
