E. Sinha, A.M. Michalak and V. Balaji
Excessive nitrogen input from rivers is a major cause of eutrophication in estuaries and coastal waters. Impacts of eutrophication include the formation of harmful algal blooms and hypoxic dead zones. These problems are widely expected to intensify with climate change. Here, we use projections of precipitation derived from climate models to explore riverine nitrogen loading for the continental United States under future climate scenarios. Anticipated changes in precipitation patterns are found to cause large and robust increases in nitrogen fluxes by the end of the century. It is therefore imperative that water quality management strategies take into account the interactions between land management and climate change.
Eutrophication, or excessive nutrient enrichment, threatens water resources across the globe. We show that climate change–induced precipitation changes alone will substantially increase (19 ± 14%) riverine total nitrogen loading within the continental United States by the end of the century for the “business-as-usual” scenario. The impacts, driven by projected increases in both total and extreme precipitation, will be especially strong for the Northeast and the corn belt of the United States. Offsetting this increase would require a 33 ± 24% reduction in nitrogen inputs, representing a massive management challenge. Globally, changes in precipitation are especially likely to also exacerbate eutrophication in India, China, and Southeast Asia. It is therefore imperative that water quality management strategies account for the impact of projected future changes in precipitation on nitrogen loading.