Speaker – Viney Aneja, NC State Department of Marine, Earth and Atmospheric Sciences. Scholarly Reassignment Seminar.

Seminar Title – Nitrogen: The Emerging Global Cycle Crisis

Abstract – Just as carbon fueled the Industrial Revolution, nitrogen has driven an Agricultural Revolution that fundamentally transformed global food production. The use of synthetic nitrogen fertilizers and cultivation of nitrogen-fixing crops expanded exponentially during the twentieth century, with the most dramatic increases occurring after 1960. This transformation has profound implications: current anthropogenic fluxes of reactive nitrogen to the biosphere now approximately equal the total flux from all natural sources combined, including both terrestrial and oceanic systems. While natural nitrogen fluxes remain subject to considerable uncertainty, anthropogenic production of reactive nitrogen has increased nearly five-fold over the past half-century. This rapid acceleration has unequivocally established human activities as a dominant force in the global nitrogen cycle, eliminating any ambiguity about the relative importance of anthropogenic versus natural fluxes. The intensification of nitrogen use has been essential for achieving the crop yields and protein production necessary to support a growing global population. However, paralleling concerns with carbon cycling, the release of fixed nitrogen into natural environments generates adverse consequences across local, regional, and global scales. As anthropogenic nitrogen contributions continue to grow relative to natural budgets, we face mounting uncertainties regarding the long-term environmental and ecological implications of this unprecedented biogeochemical perturbation.