Nitrogen: Cascading Through Time
Abstract
The First World War began July 1914 and ended November 1918; approximately 16 million people died. It probably would have ended sooner, and the casualties would have been less, but for the development of the Haber-Bosch (HB) process. In 1908 Fritz Haber synthesized NH3 from its elements; in 1913, Germany started industrial-scale NH3 production using the process developed by Carl Bosch. One year later, AGU was founded. On both counts, the Earth, and our understanding of it, has not been the same since.
100 Years Ago: The world population was 1.8 billion. The major processes of the N cycle were well known. Biological N fixation (BNF) was the most important process that converted di-atomic N to reactive N (Nr). Fossil fuel combustion was a trivial source of Nr. Food production was sustained by naturally occurring stocks of N (i.e., manure, nitrate deposits, guano) and by agricultural land expansion. On a global basis, the N cycle was in a quasi-natural state. Now: The world population is 7.6 billion. On a global basis, human creation of Nr by the HB process, fossil fuel combustion and cultivation-induced BNF is several-fold greater than natural terrestrial BNF. Denitrification of anthropogenic N has not kept up with its creation rate—thus Nr is accumulating in environmental reservoirs. The impacts of excess Nr are causing serious changes to Earth systems due to smog, acid rain, eutrophication, atmosphere warming and stratospheric ozone depletion, all connected by the N cascade. The pulse of the planet has quickened. 50 Years From Now: There will be more people—the median estimate of population is 10 billion. They will eat food and N will be needed to produce the food. If current trends continue with respect to increasing per-capita meat consumption, by 2050 the Nr created for food production will increase from 160 Tg N/yr to 320 Tg N/yr. The pulse of the planet will continue to quicken. Opportunities for Action: A doubling of Nr creation in support of food production is not sustainable with respect to a healthy environment. The good news is that multiple actions can be taken, including increasing N utilization efficiency of food production, minimizing food waste along the supply chain, changing diets and consumer education about N-related issues. This paper will explore the challenges facing society to implement these actions.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B41B..05G
- Keywords:
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- 0498 General or miscellaneous;
- BIOGEOSCIENCESDE: 0499 New fields (not classifiable under other headings);
- BIOGEOSCIENCES