The Climate Benefits of Improving Water Quality

Eutrophication of surface waters enhances greenhouse gas (GHG) emissions. Policies that ameliorate eutrophication by limiting nutrient loadings to surface waters, in turn, reduce these GHG emissions. However, these reductions are not considered in evaluations of nutrient management policies. The present study addresses this gap by modeling GHG reductions from a large-scale nutrient management program in America’s largest estuary. We estimate climate benefits of over $300 million over the first 50 years of the program. We extrapolate our results to the largest river basin in the U.S.—a primary contributor to the hypoxic dead-zone in the Gulf of Mexico—and estimate the climate benefits of a comparable policy would exceed $10 billion over the first 40 years of the program. Our findings suggest that reductions in GHG emissions from nutrient management programs should not be overlooked when evaluating the societal benefits of such policies.