TOP 100 CAMPING SITES
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| Phosphorus Famine: The Threat to Our Food Supply As complex as the chemistry of life may be, the conditions for the vigorous growth of plants often boil down to three numbers, say, 19-12-5. Those are the percentages of nitrogen, phosphorus and potassium, prominently displayed on every package of fertilizer. In the 20th century the three nutrients enabled agriculture to increase its productivity and the world’s population to grow more than sixfold. But what is their source? We obtain nitrogen from the air, but we must mine phosphorus and potassium. The world has enough potassium to last several centuries. But phosphorus is a different story. Readily available global supplies may start running out by the end of this century. By then our population may have reached a peak that some say is beyond what the planet can sustainably feed.Moreover, trouble may surface much sooner. As last year’s oil price swings have shown, markets can tighten long before a given resource is anywhere near its end. And reserves of phosphorus are even less evenly distributed than oil’s, raising additional supply concerns. The U.S. is the world’s second-largest producer of phosphorus (after China), at 19 percent of the total, but 65 percent of that amount comes from a single source: pit mines near Tampa, Fla., which may not last more than a few decades. Meanwhile nearly 40 percent of global reserves are controlled by a single country, Morocco, sometimes referred to as the “Saudi Arabia of phosphorus.” Although Morocco is a stable, friendly nation, the imbalance makes phosphorus a geostrategic ticking time bomb. [More] rss.sciam.com |
Can Rooftop Solar Systems Serve Whole Neighborhoods? Dear EarthTalk: I know of solar power systems that people can put on their roofs to generate electricity or heat water. Are there systems that serve whole neighborhoods? -- Lee Helscel, via email [More] rss.sciam.com |
Fossils for All: Science Suffers by Hoarding In June the famed Lucy fossil arrived in New York City. The 3.2-million-year-old partial skeleton of Australopithecus afarensis could attract hundreds of thousands of visitors over the course of her four-month engagement--part of a six-year tour that began in 2007.Before this tour, Lucy had never been on public display outside of Ethiopia. One might expect scholars of human evolution to be delighted by the opportunity to share the discipline’s crown jewel with so many members of the science-interested public. But news reports announcing her New York debut included the same objections that aired when she first landed in the U.S.: namely, that the bones could sustain damage and that the tour takes a key specimen out of scientific circulation for too long. Indeed, some major museums turned the exhibit away in part for those reasons. [More] rss.sciam.com |
Britain's rare birds get more common, as common birds get rarer More than half of the U.K.'s rarest birds have seen recent population increases, according to the 10th annual "State of the U.K.'s Birds" report (pdf) . rss.sciam.com |
What Would Failure to Combat Climate Change Quickly Mean? BOULDER, Colo. – Turns out climate policy has some tipping points. [More] rss.sciam.com |