James N. Galloway1, Allison M. Leach2, Jan Willem Erisman3 and Albert Bleeker4
1Department of Environmental Sciences, University of Virginia, 291 McCormick Rd, Charlottesville, VA 22904, USA, firstname.lastname@example.org
2Department of Natural Resources and the Environment, University of New Hampshire, Durham, New Hampshire 03824, USA.
3Louis Bolk Institute, Hoofdstraat 24, 3972 LA Driebergen, The Netherlands Department of Earth Sciences, Earth and Climate cluster, VU University Amsterdam, Amsterdam, The Netherlands
4Department of Water, Agriculture and Food, The Netherlands Environmental Assessment Agency, Bezuidenhoutseweg 30, The Hague, The Netherlands.
Once upon a time there was enough naturally occurring nitrogen (N) to provide food for the world’s peoples. Then there was not in the western regions. Now there is. But this transition from plenty, to scarcity, to plenty has come with a tremendous environmental cost. This paper provides an historical overview of the growth of knowledge about N and about its impacts, both positive and negative. The paper also explores three scenarios of what might have been if in 1700 the world had the N-Knowledge that we have now. The paper then projects N use to feed the world’s people in 2050 under three scenarios of per-capita protein consumption: increasing, constant, and decreasing to nutritional guidelines. The three projected results for 2050 annual N use from producing and consuming food are 320 Tg N, 230 Tg N and 170 Tg N, respectively. Given that the first scenario (increasing protein) is most likely without utilizing our N-Knowledge, the paper ends with suggestions for improvements in N management.