J. Lovelock (1988) argues that planet Earth—atmosphere, ecosphere, geosphere, and hydrosphere—is a single ecosystem/organism, regulating itself by feedback between its abiotic and biotic components. Lovelock stresses the overriding importance of Gaia, rather than any individual species. Kleidon (2002) Climatic Change 52, 3 concludes that life on Earth tends to enhance carbon uptake.
Gaia tends to equilibrium, but human agency seems to be overriding its regulatory mechanism. ‘We have spread thousands of toxic chemicals worldwide, appropriated 40% of the solar energy available for photosynthesis, converted almost all of the easily arable land, dammed most of the rivers, raised the planet sea level, and now…are close to running out of fresh water. A collateral effect of all this genetic activity is the continuing extinction of wild ecosystems, along with the species that compose them. This also happened to be the only human impact that is irreversible’ (E. O. Wilson 2006).