Five years ago researchers on the island of Flores in Indonesia found bones of a miniature human species, the Homo floresiensis. The hobbit, as it came to be known, had such a tiny brain for its period that scientists dared to cast doubt on the veracity of the theory of evolution. The paleoanthropological community was aghast. But, after more digging, the theory of evolution survived the hobbit and the paleoanthropological community recovered its equipoise.

On the subject of climate change, there appears to be plenty of people who have discovered a hobbit. The poll in The Times today reveals that only 41 per cent of respondents believe that climate change is happening and that human causation is an established fact. A third of the public believes in the fact of climate change but remains unpersuaded that it is the work of human hands. Nearly one in ten people believes that climate change is a purely natural phenomenon and blaming humans is propaganda put about by environmentalists. Fifteen per cent of the country simply do not accept that climate change is happening at all.

There has clearly been a serious failure of political communication but the last group at least should be easy to convince. The decade from 1998 to 2007 is the warmest on record. Of the top ten warmest years in this country, eight have happened since 1997. If the concentrations of greenhouse gases and aerosols stabilised at the levels found at the turn of the century, we would still expect global temperatures to reach 1.4C above pre-industrial levels by 2100. The sea is rising at an accelerated rate. In some parts of the world there have been statistically significant increases in precipitation and rainfall and Asia and Africa have seen an increased frequency and intensity of droughts. Mountain glaciers in non-polar regions have retreated significantly.

Sophisticated critics, of course, do not deny any of this. They argue that change is constant in the natural world, not that it has miraculously ceased. They deny not climate change but human causation, suggesting instead that global warming is due, variously, to the Sun, volcanoes and el Niño. Fifty-nine per cent of the respondents to this newspaper’s poll do not, for one reason or another, believe that human action is responsible for climate change.

Again, the failure of political communication is very stark. None of the main parties has yet succeeded in making this issue its own. Yet the case is overwhelming. The Intergovernmental Panel on Climate Change was written by 152 scientists from more than 30 countries and reviewed by more than 600 experts. It concluded that most of the observed increase in global average temperatures since the mid-20th century is due to the observed increase in man-made greenhouse gas concentration. Concentrations of CO2 have increased by more than 35 per cent since industrialisation began, and they are now at their highest for at least 800,000 years. Natural factors alone cannot, on any but the most extraordinary assumptions, get anywhere close to the temperature rises that have been witnessed. Hardly any serious scientists dispute this any longer.

It is possible that the collective expertise of brilliant scientists could be wrong. The best minds in the world once held a geocentric theory of the solar system. Before the discovery of sub-atomic particles they believed that everything was made of earth, air, fire and water. Right up to the 19th century, serious scientists wrote recipe books for making animals. But no previous process of scientific trial, error and progress has ever overturned such a well-attested thesis. Lord Rees has reminded us that we now live in a global village and it is, he pointed out, probably inevitable that there will be some global village idiots.