Lovelock's hypothesis was often dismissed as fantasy. Rooted in deep ecological thought it supported strong ecocentric philosophy during a period of immense technological revolution, which is still going. As Lovelock himself explains (see video below, from 10:45-12:00 min) the mistake made by both physical scientists and biologists was to treat processes as separate. In more recent years, climate scientists have considered how to integrate biodiversity processes into climate models, to provide more realistic predictions of how Earth systems operate.
Far from being a deep-ecologist, Lovelock was unique as an atmospheric scientist with the foresight to understand systems that climatologists are only just now beginning to take for granted. In his recent book Gaia: the Revenge Lovelock paints a very pessimistic picture of the future. Other scientists are more optimistic and whether Lovelock will again be right, remains to be seen.
In the mean time, Lovelock's wisdom still reinforces the principal that loss of biodiversity is a key driver of climate change, and not just a consequence of it. Whatever the outcome of climate change, whether it is reversible or not, this has profound implications for the ecological profession and the robust implementation of biodiversity planning law and policy.
The following video is a recent presentation to the Royal Society in London.