A couple of citations from Christian De Duve, Vital Dust about Gaia, p. 220-221.
http://en.wikipedia.org/wiki/Gaia_hypothesis
She was the Mother Earth goddes of the ancient Greeks. Long forgotten, except in such words as geology, geography, and geometry, she has recently been revived by James Lovelock, a distinguished English scientist, an F.R.S. (Fellow of the Royal Society), the most coveted set of initials to follow a British scientist’s name. A physisist by training, Lovelock is a successful inventor of scientific instruments who enjoys a comfortable income from the patents he earned when he was young. He now lives as the proverbial “gentleman of independent means” in a converted eighteenth-century water mill near the border between Devon and Cornwall, the most sourthwestly English counties. Coombe Mill (Experimental Station) is both Lovelock’s home and the computer-crammed laboratory in which he simulates the whims and vagaries of Gaia.
What distinguishes Gaia from other global concepts is homeostasis, self-regulation. In Gaia, life and Earth do not simply interact haphazardly. They do so in a manner that tends to correct the imbalances they inflict on each other.
According to the Gaia theory, the Earth is a living organism that automatically regulates its environment so as to make it optimal for life.
The history of life on Earth offers some support for Lovelock’s general point of view. This history has gone through repeated catastrophes, due to such causes as tectonic movements, volcanic eruptions, climatic changes, and asteroid impacts, that wiped out much of the existing flora and fauna. Each time, life not only rebouned but came up with dome decisivie innovations. However, it took millions of years for this to happen. We can harldy rely on Gaia’s natural resilience if we wish to save the Earth for our children and grandchildren.