A new study by 22 biologists and ecologists has found that environmental changes on our planet are reaching a point of no return that leads to mass extinctions and harms human welfare. The situation, said one scientist, “scares the hell out of me.” That would be James H. Brown, one of the authors of alarming paper published by Nature, talking to New York Times Green blogger Justin Gillis. Brown is not one of your everyday cranks predicting raptures and the end of days. He is a macroecologist at the University of New Mexico. And as The Atlantic's James Fallows, who pointed out this terrifying study to us, writes, this could be the most important news of 2012. How soon do these scientists expect the world as we know it to end? Gillis writes, "within a few human generations, if not sooner." The most frightening thing is that this finding isn't about what will come if we do not act, but that our effects on the planet's environment -- global warming, population growth, and overall resource extraction -- means that we've already passed a "tipping point." This isn't a plea for change. These are things scientists have been warning us about for decades.

Here's a video from one of the scientists involved: