Five years go an impressive, international group of scientists unveiled nine biological and environmental “boundaries” that humankind should not cross in order to keep the earth a livable place. To its peril, the world had already crossed three of those safe limits: too much carbon dioxide in the atmosphere, too rapid a rate of species loss and too much pouring of nitrogen into rivers and oceans—primarily in the form of fertilizer runoff.
Read more: http://ift.tt/156jD0s
No comments:
Post a Comment