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INDICATORS OF CHANGE IN THE MID-ATLANTIC WATERSHEDS AND CONSEQUENCES OF CLIMATE IN UPPER CHESAPEAKE BAY
Citation:
Walker, H A., B. Yarnal, V. Berounsky, E H. Dettmann, J S. Latimer, AND N A. Jaworski. INDICATORS OF CHANGE IN THE MID-ATLANTIC WATERSHEDS AND CONSEQUENCES OF CLIMATE IN UPPER CHESAPEAKE BAY. Presented at 5TH Annual NHEERL Symposium. Indicators in Health and Ecological Risk Assessment, Research Triangle Park, NC, June 6-8, 2000.
Description:
The rate of change in Northern Hemisphere atmospheric temperature in the past century relative to the preceding millennium strongly suggests that we are in a period of rapid global climate change. The mid-Atlantic region is quite sensitive to larger scale climate variation, which effects the frequency and severity of storminess, drought, and flooding. Human activity enhances that sensitivity to climate variation. There are increasing risks associated with climate extremes because of the anthropogenic alteration of watersheds. Due to increases in nutrient loading to watersheds, nitrogen flux per unit flow has increased over time. Wet years now have different consequences in coastal receiving waters than equivalent wet years in previous centuries. In addition, increasing demands for water mean that regional drought can have increasing adverse impacts. We illustrate these points using a combination of proxy indicators from the past 300 years using tree rings and marine sediment cores, and modern observations. Time series with monthly resolution from the past century illustrate variations in: 1) soil moisture based on NOM climate division data, and 2) nutrient inputs and water quality changes in the Potomac River. Basin-scale variations in the Palmer Drought Severity Index are estimated for upper Chesapeake Bay watersheds and associated with water quality changes in the Potomac River and Chesapeake Bay. Consequences of climate variation on the Potomac estuary, and mid-Chesapeake Bay illustrate ecosystem sensitivity to climate variation and increasing human and ecological vulnerability to both wet and dry extremes of climate. This abstract does not necessarily reflect US EPA policy.