The article is obviously intended to promote the book... on the other hand, he raises some interesting points I haven't heard elsewhere, at least in so dramatic a fashion. On the aerosol problem, Lovelock notes that a decline in civilized industry would clear dust and aerosols from the atmosphere, allowing more sunlight through (a recently noted phenomenon of "global dimming" over the past century is attributed to aerosol pollutants), and hence increasing the warming effect. Other feedbacks are present that could exacerbate atmospheric carbon dioxide. Conversion of large tracts of tropical forest to desert will greatly reduce Earth's capacity to maintain relatively steady temperatures, and dramatic sea level rise and loss of arable land will greatly reduce the food we can grow. Etc.
Lovelock claims there is no solution available in time to avert the disaster - in part for the political reasons that the primary sources of the problem for the coming century - the US, China, and India - do not recognize and are doing little to avert the problem; it matters little what Britain or Europe do in the face of far worse abusers of our planet.
A sample phrase from the article captures the ultimate forecast: "We are in a fool's climate, accidentally kept cool by smoke, and before this century is over billions of us will die and the few breeding pairs of people that survive will be in the Arctic where the climate remains tolerable."
I don't think Lovelock is right about the political issues - but I do think he's right about the scale of the problem; it's more urgent than ever that we change course in the nations that can make a difference.