1950s but since then has increased and more accurate delivery could up excess nitrogen before it can exponentially. (See Figure 2: cut this waste substantially. damage aquatic systems. Trends in Fertilizer Consumption, Cutting airborne nitr t none of these steps is easy 1961-1997) emissions from fossil fuels will or obvious. and there seems little In fact, one half of all the also be important and will benefit likelihood of concerted action commercial fertilizer ever from many of the same strategies until the nitrogen threat is produced has been applied since used to reduce carbon dioxide elevated to a higher global profile. 1984 Socci 1997). The problem is emissions, including a greater While the risks of global warming hat about one half of every mphasis on energy efficiency, a from a buildup of greenhouse metric ton of fertilizer applied gradual shift toward alternative gases in the atmosphere are fairly fields never even makes it into ergy sources, and the use of common knowledge today, the plant tissue but ends up ow-nitrogen technology in power dangers of the worlds heavy evaporating or being washed into plants and cars. Other strategies habit have gone largely local watercourses (Vitousek et al. make as well, such as unheralded so far, although this 1997: 13). A combination of better restoration of wetlands, which are habit may be as pervasive and as timing of fertilizer applications, natural nutrient traps that sponge hard to address as cutting more exact calculation of doses greenhouse gas emission REFERENCES Anderson, D M. 1994. Red Tides, "Scientific American(August): 62-68 Asner, G.,T. Seastedt, and A. Townsend. 1997. The Decoupling of Terrestrial Carbon and Nitrogen Cycles luman Influences on Land Cover and Nitrogen Supply Are Altering Natural Biogeochemical Links in the Biosphere, "BioScience 47(4): 226-234 Diaz, R.J. and R. Rosenberg. 1995. " Marine Benthic Hypoxia: A Review of Its Ecological Effects and the Behavioral Responses of Benthic Macrofauna, "Oceanography and Marine Biology: An Annual Review 33: 245- 02. Food and Agriculture Organization of the United Nations. 1999. FAOSTAT on-line statistical service(FAO, Rome).Availableonlineathttp://www.fao.org ordan, T. and D. Weller. 1996. Human Contributions to Terrestrial Nitrogen Flux: Assessing the Sources and Fates of Anthropogenic Fixed Nitrogen, BioScience 46(9): 655-664 Pearce, F. 1997. "Planet Earth Is Drowning in Nitrogen, New Scientist(April 12: 10 Socci, T. 1997. "Ecological Consequences of Human-Induced Changes in the Global Nitrogen Cycle, "U.S Global Change Research Program briefing paper(February 26 Vitousek, P. et al. 1997. "Human Alteration of the Global Nitrogen Cycle: Causes and Consequences, " Issues In Ecology 1: 2-16 Warrick, ]. 1997. Dead Zone'Plagues Gulf Fishermen, The Washington Post(August 24): 1, sec. A Wedin, D and D. Tilman. 1996. Influence of Nitrogen Loading and Species Composition on Carbon Balance of Grasslands. " Science 274: 1720-1723. CEarthTrends 2001 World Resources Institute. All nights reserved. Fair use is permitted on a limited scale and for educational purposes.©EarthTrends 2001 World Resources Institute. All rights reserved. Fair use is permitted on a limited scale and for educational purposes. 3 1950s but since then has increased exponentially. (See Figure 2: Trends in Fertilizer Consumption, 1961–1997) In fact, one half of all the commercial fertilizer ever produced has been applied since 1984 (Socci 1997). The problem is that about one half of every metric ton of fertilizer applied to fields never even makes it into plant tissue but ends up evaporating or being washed into local watercourses (Vitousek et al. 1997:13). A combination of better timing of fertilizer applications, more exact calculation of doses, and more accurate delivery could cut this waste substantially. Cutting airborne nitrogen emissions from fossil fuels will also be important and will benefit from many of the same strategies used to reduce carbon dioxide emissions, including a greater emphasis on energy efficiency, a gradual shift toward alternative energy sources, and the use of low-nitrogen technology in power plants and cars. Other strategies make sense as well, such as restoration of wetlands, which are natural nutrient traps that sponge up excess nitrogen before it can damage aquatic systems. But none of these steps is easy or obvious, and there seems little likelihood of concerted action until the nitrogen threat is elevated to a higher global profile. While the risks of global warming from a buildup of greenhouse gases in the atmosphere are fairly common knowledge today, the dangers of the world's heavy nitrogen habit have gone largely unheralded so far, although this habit may be as pervasive and as hard to address as cutting greenhouse gas emissions. REFERENCES Anderson, D. M. 1994. "Red Tides," Scientific American (August):62–68. Asner, G., T. Seastedt, and A. Townsend. 1997. "The Decoupling of Terrestrial Carbon and Nitrogen Cycles: Human Influences on Land Cover and Nitrogen Supply Are Altering Natural Biogeochemical Links in the Biosphere," BioScience 47(4):226–234. Diaz, R. J. and R. Rosenberg. 1995. "Marine Benthic Hypoxia: A Review of Its Ecological Effects and the Behavioral Responses of Benthic Macrofauna," Oceanography and Marine Biology: An Annual Review 33:245– 302. Food and Agriculture Organization of the United Nations. 1999. FAOSTAT on-line statistical service (FAO, Rome). Available online at: http://www.fao.org. Jordan, T. and D. Weller. 1996. "Human Contributions to Terrestrial Nitrogen Flux: Assessing the Sources and Fates of Anthropogenic Fixed Nitrogen," BioScience 46(9):655–664. Pearce, F. 1997. "Planet Earth Is Drowning in Nitrogen," New Scientist (April 12):10. Socci, T. 1997. "Ecological Consequences of Human-Induced Changes in the Global Nitrogen Cycle," U.S. Global Change Research Program briefing paper (February 26). Vitousek, P. et al. 1997. "Human Alteration of the Global Nitrogen Cycle: Causes and Consequences," Issues In Ecology 1:2–16. Warrick, J. 1997. "Dead Zone' Plagues Gulf Fishermen," The Washington Post (August 24):1, sec. A. Wedin, D. and D. Tilman. 1996. "Influence of Nitrogen Loading and Species Composition on Carbon Balance of Grasslands," Science 274:1720–1723