That something strange is happening to our planet is clear. And until very recently, the root cause had seemed beyond question. In the months leading up to the Copenhagen summit, there appeared to be little room for debate: global warming theory had become a political orthodoxy. We all wanted to do the right thing and save the Earth by swapping incandescent bulbs for fluorescent ones, turning off computers, recycling and saving water. Trying to stop it getting too warm outside made us feel all warm inside - even if many of our actions were still not particularly rational: we continued to drive our cars (how could we get to work otherwise?), fly away on holiday (we all need a break, don't we?) and leave our televisions on standby.

Irrationality and science may seem unlikely bedfellows, but the history of science is littered with outcomes determined not by rational argument but by irrational prejudices.

Take the famous case of whether the Earth orbits the Sun or the Sun orbits the Earth, for example. Galileo, despite lacking vital evidence to support the heliocentric view, used his skills as a rhetorician and polemicist to force one of the great "paradigm shifts" - and after him the Earth began obediently orbiting the Sun. In this case, irrationality ushered in a better model of the Universe.

Climate change is the most important issue of our lifetime. With so much at stake, some researchers have become eco-evangelists. For the sceptics, it is not a matter of denial or heresy; it is just that the thought that we are killing the very planet that sustains us is too huge to contemplate. If they can find any error, however insignificant, in the "science" or any bias in its presentation, it allows them to dismiss all the evidence, breathe a sigh of relief and get on with life as usual.

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In this week's cover feature, philosopher Martin Cohen warns that the current consensus on global warming owes less to science than to PR and fear-mongering. By packaging myths as "science", they become irrefutable.

For this very reason, the scientific community must tread carefully. As academics at the University of East Anglia's Climatic Research Unit discovered, it's dangerous to position yourself on the side of the angels because the devil lurks in the detail. The leaked email scandal has made many people question researchers' impartiality. But this is not some kind of religion, and scientists are not its priests. Mike Hulme, professor of climate change at UEA's School of Environmental Science, says climate scientists must be "less tribal" in attitude. They should, in fact, be neutral, there to do the research and present the results openly. Public trust in their neutrality and transparency is vital.

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The Met Office now says that it will release and re-examine 160 years of temperature data in an attempt to restore public confidence in climate-change science. According to The Times, the Government wanted to stop it doing so, saying that it would be seized upon by climate-change sceptics.

Real science doesn't need a PR leg-up. It is not politics. It is about getting to the truth, however inconvenient. Throughout the ages there have been doubters, sceptics, people who have questioned the reigning orthodoxy. They have been vital, poking at our beliefs, shaking a stick at our certainties. Science must be tested. It is the only way knowledge advances.

ann.mroz@tsleducation.com.