The Revenge of Gaia is not a book to read should you be feeling a bit down, a bit uncertain about the future, worried about the grandkids. Should, however, you be seeking a scientific foundation for an apocalyptic, end-of-the-human-race novel, it would be just the ticket.

But this is far from fiction, which is what makes it so scary; it is the considered, quite probably final, view of the likely future from the now 80-plus James Lovelock, the man who 40 years ago conceived the theory of Gaia - in his words:

A view of the Earth that sees it as a self-regulating system made up from the totality of organisms, the surface rocks, the ocean and the atmosphere tightly coupled as an evolving system. The theory sees this system as having a goal - the regulation of surface conditions so as always to be as favourable as possible for contemporary life.

The problem that Lovelock identifies in The Revenge of Gaia is that she's getting hotter. (Why the gender? Well the name comes from an ancient Greek goddess, so it seems fair enough.) In part that's an extremely long-term trend - the sun at the earth's birth was probably about 25 per cent less luminous than it is now. It was only in a window about two billion years ago that the temperature was just right for life to start (before that it was too cold), and in about one billion years the heat will be unbearable for Gaia, Lovelock says, and the Earth will be lifeless. But that's a process we could hurry along, by both destroying the natural systems such as forests that help to cool, while also pumping heating gases into the atmosphere.

We think of warmth as enhancing growth, being more productive, but in the great photosynthetic powerhouse of the oceans, that isn't the case. It was during the great glacial periods, with comparatively little warm water, and great expanses of chilled ocean water, teeming with life, that Gaia was at her richest, plus with all of that water locked up in ice, an extra spread of land, at its greatest extent equal to the area of Africa.