Humans Cross Another Danger Line for the Planet
Five years ago 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.
Now we have succeeded in transgressing a fourth limit: the amount of forestland being bulldozed or burned out of existence (see map below). Less and less forest reduces the planet’s ability to absorb some of that carbon dioxide and to produce water vapor, crucial to plant life.
