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Climate Strategy Impact on Nitrogen Deposition in the USA
Citation:
Baublitz, C., B. Henderson, Dan Loughlin, Chris Nolte, D. Henze, AND H. Lee. Climate Strategy Impact on Nitrogen Deposition in the USA. Presented at A&WMA’s 109th Annual Conference & Exhibition, New Orleans, LA, June 20 - 23, 2016.
Impact/Purpose:
In this extended abstract, the author demonstrates how the emission outputs of an integrated assessment model can be applied to examine changes in ecosystem damage from nitrogen deposition under climate change mitigation scenarios.
Description:
Nitrogen (N) leakage to the environment in the United States costs an estimated $210 billion per year, equivalent to 1-3% of the national GDP, in part due to atmospheric N pollution. Excess N deteriorates ecosystems via eutrophication in water bodies, causing fish kills and additional expense in water treatment (Sobota et al., 2015). To describe the nutrient threshold an ecosystem is able to withstand before its functionality is impaired, the Department of Agriculture developed critical loadings for ecoregions and vegetation types across the U.S. (Pardo et al., 2015). In present conditions, N deposition alone may cause sensitive ecosystems across the United States to exceed these values (Lee et al., 2015). Although the primary contributor to N deposition in the past has been in oxidized forms, or NOx, ammonia (NH3) is expected to be the predominant form in the future as air quality regulations reduce NOx emissions (Ellis et al., 2013). Climate change mitigation measures complicate N projections because many are expected to provide air quality co-benefits through NOx reductions. However, strategies that substitute biofuels for conventional petroleum could lead to an increase in NH3 emissions from fertilizer application. In evaluating climate mitigation strategies, it is imperative that we understand their effects on the N cycle to avoid economic, public health and ecological consequences.