Nitrogen Fertilizer: Agricultural Breakthrough – And Environmental Bane
One hundred years ago this month, a laboratory experiment at the University of Karlsruhe in Germany set the stage for the Green Revolution. Chemist Fritz Haber placed a sheet of osmium in a steel chamber, pumped in a mix of nitrogen and hydrogen...
March 20, 2009 | Source: Scientific American | by Sarah SimpsonMar
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One hundred years ago this month, a laboratory experiment at the University of Karlsruhe in Germany set the stage for the Green Revolution. Chemist Fritz Haber placed a sheet of osmium in a steel chamber, pumped in a mix of nitrogen and hydrogen gases, and cranked up the heat and pressure. Then, out flowed ammonia, the elusive raw material for producing synthetic fertilizer. It was the eureka moment scientists had been pursuing for a decade: Haber managed to create the necessary conditions to transform nitrogen gas, abundant in the atmosphere but useless for life, into a digestible form. The work would earn Haber the 1918 Nobel Prize in Chemistry. (Many protested the award because Haber had been instrumental in developing and deploying chlorine gas for Germany during World War I.)
Once implemented on an industrial scale, ammonia synthesis enabled the widespread fertilization of croplands for decades hence. As a direct result, the world’s population skyrocketed from 1.6 billion to six billion during the 20th century. But Haber’s nourishing discovery has a dark side he probably never imagined. The boom of fertilizer, long injudiciously applied, has come at a high price for the environment.
And now, according to a new report to be released later this month by the Scientific Committee on Problems of the Environment (SCOPE) of the International Council for Science, society’s aspiration to use biofuels to kick its oil addiction could backfire. By intensifying nitrogen pollution, a business-as-usual approach to biofuels production could exacerbate global warming, food security threats and human respiratory ailments in addition to familiar ecological problems. Scientists have long known that the reactive nitrogen in fertilizers leaching from agricultural fields (as well as those smaller amounts exiting tailpipes and smokestacks) wreak havoc as they cascade through the air and rivers. Rogue nutrients often spur harmful algal blooms as they flow into the ocean, and hundreds of estuaries around the world suffer from so-called seasonal dead zones as a result. “We’re getting to the point where dead zones will be continuous bands around the continents,” warns marine ecologist Jeremy Jackson of Scripps Institution of Oceanography in La Jolla, Calif.