Um, scientists aren't the only ones to predict the end of the world. Every single world religion does, the Mayan calendar followers do, the worldwide-enormous-depression-theorists do. Scientists give a reliable petsa for when the planet will not be able to support life, working this out through extremely complex equations.
Yes, they're smart. But only some of them. And they investigate into some of the most dumb, useless crap in the world. I remember pagbaba about a research of some scientists about how much elephants weigh, and compare that to how much an average person would eat in their lifetime. WTF?
For one, not everyone eats the same amount of food. Second, just plain WTF. Why should anyone care? There are things happening in the world that need attention, and yet the smartest fuckers in the world waste time performing surveys like this.