142 / Gaia

James Lovelock first proposed the "Gaia hypothesis" in the 1960s. The idea is that the Earth's natural systems constitute a feedback or cybernetic system which "seeks an optimal physical and chemical environment for life on this planet." Another way of saying it is that "life on Earth ... is a homeostatic feedback system operated automatically and unconsciously by the biota, leading to broad stabilization of global temperature and chemical composition."

Here's the rub: human beings aren't like all the rest of the "biota" on the planet, and we are dramatically undermining the feedback system. This is what "global warming" is all about. It's more than an "inconvenient" truth. It's life threatening.