Ambiente - Salute - Diritti Umani - Nutrizione - Agricoltura

In 1972, a junior at Oregon State University bought a small paperback for $2.75 titled “The Limits to Growth.” Citing the rate at which the population was expanding and the spread of industrialization, it projected a dismal future for the planet. The book, by a group of M.I.T. researchers, made a deep impression on the student, Steven Running, a botany major.
Forty years later, the prediction is being borne out, said Dr. Running, who is now a forest ecologist at the University of Montana and directs the university’s Numerical Terradynamic Simulation Group. Humans are approaching the limits of the globe’s finite plant life, he argues in an article published online on Thursday in the journal Science.
Since 2000, Dr. Running and his colleagues have monitored how much plant growth covers terra firma, using two NASA satellites in the agency’s Earth Observing System. After they crunched the numbers, combining the current monitoring system’s data with satellite observations dating back to 1982, they noticed that terrestrial plant growth, also known as net primary production, remained relatively constant. Over the course of three decades, the observed plant growth on dry land has been about 53.6 petagrams of carbon each year, Dr. Running writes in the article.
This suggests that plants’ overall productivity — including the corn that humans grow and the trees people log for paper products — is changing little now, no matter how mankind tries to boost it, he said. (...)

The article:
http://green.blogs.nytimes.com/2012/09/20/has-plant-life-reached-its-limits/?smid=tw-nytimesscience&seid=auto