- 2,99 €
Nearly four decades have passed since the phrase "global warming" first appeared in a scientific journal. Writing in Science in 1975, geochemist Wallace Broecker warned that rising atmospheric carbon dioxide ([CO.sub.2]) levels would result in a world climate unprecedented in modern human history. Now, as Broeckers forecast is becoming a reality, we can no longer just debate ways to slow climate change; we must figure out how to live with it. Although much of the work in this area has focused on the carbon cycle, expanding our focus to other elements, especially nitrogen and phosphorus, can make a positive contribution. By providing more fertilizers to farmers in some of the world s poorest nations and reducing nitrogen and phosphorus losses to the environment in developed and rapidly developing ones, we could reduce some of the risks of a changing climate. At the same time, a more efficient, less polluting relationship with the global nitrogen and phosphorus cycles would mitigate a host of other environmental challenges, increase food security, improve human welfare, lessen some national security concerns, and probably save money. A century ago, world leaders were asking how they would be able to feed a fast-growing population. At the time, the potential for food growth was constrained by finite reserves of nitrogen and phosphorus that could be readily accessed for crop fertilizers. Only two generations later, the situation was entirely different. Widespread implementation of the Haber-Bosch process--an industrial means for converting the limitless pool of atmospheric [N.sub.2] into usable forms of nitrogen, including fertilizer--had released much of the world from nitrogen constraints on crop growth. In parallel, the ability to locate and mine reserves of phosphorus rose markedly. In combination with revolutions in plant breeding and genetics, these developments formed the foundation for the Green Revolution, rapidly increasing world food production.