But one of the world's leading experts on polar bears has been told to stay away from this week's meeting, specifically because his views on global warming do not accord with those of the rest of the group. Dr Mitchell Taylor has been researching the status and management of polar bears in Canada and around the Arctic Circle for 30 years, as both an academic and a government employee. More than once since 2006 he has made headlines by insisting that polar bear numbers, far from decreasing, are much higher than they were 30 years ago. Of the 19 different bear populations, almost all are increasing or at optimum levels, only two have for local reasons modestly declined. Dr Taylor agrees that the Arctic has been warming over the last 30 years. But he ascribes this not to rising levels of CO2 – as is dictated by the computer models of the UN's Intergovernmental Panel on Climate Change and believed by his PBSG colleagues – but to currents bringing warm water into the Arctic from the Pacific and the effect of winds blowing in from the Bering Sea.
Dr Taylor had obtained funding to attend this week's meeting of the PBSG, but this was voted down by its members because of his views on global warming. The chairman, Dr Andy Derocher, a former university pupil of Dr Taylor's, frankly explained in an email (which I was not sent by Dr Taylor) that his rejection had nothing to do with his undoubted expertise on polar bears: "it was the position you've taken on global warming that brought opposition". Dr Taylor was told that his views running "counter to human-induced climate change are extremely unhelpful". His signing of the Manhattan Declaration – a statement by 500 scientists that the causes of climate change are not CO2 but natural, such as changes in the radiation of the sun and ocean currents – was "inconsistent with the position taken by the PBSG".
The average temperature at midsummer is still below zero, the latest date that this has happened in 50 years of record-keeping.