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CRITICAL LOADS METHODS
Citation:
RINGOLD, P. L. CRITICAL LOADS METHODS. Presented at Multi-Agency Critical Loads Workshop at The University of Virginia, Charlottesville, VA, May 23 - 25, 2006.
Description:
I summarize the results of an interagency project that 1) defines a generic approach to quantifying and reporting critical loads, and 2) exercises that generic approach by examining a data rich system -- the critical loads of sulfur deposition and it's effect on the chronic acidification of lakes inthe northeastern United States. The extent and characteristics of thisresource are well defined as a result of statistically designed surveys. We select two different chemical indicators, an ANC of 0 µeq/liter and 25, that can be linked by empirical observation to biological losses in lakes. We then estimate the critical load required to achieve these two chemical levels with two static models and with two dynamic models. We map these results using several different regionalization schemes. Last, we use an integrated assessment system of emissions, cost, transport and deposition models to evaluate the results of using these different methods to define critical loads. We offer several key conclusions. The first is that the development of critical loads estimates requires an understanding of the anticipated use and therefore an intimate, iterative and informed dialogue between those formulating policy and those conducting critical loads analyses. The second is that the development and evaluation of critical loads estimates should be done inthe context of the temporal and spatial scales of the relevant ecological and emissions systems. The third is that system level monitoring, especially ecosystem level monitoring is most important.