Sir - It is hard to imagine what is the basis of Michael Tyce's confident assertion that climate change impacts "will be virtually imperceptible", (Letters, November 2), or whence the generous room for doubt offered by "CO2 emission may have some insignificant effect"!

Possibly he has information that is not known to the 600 odd scientists who put their name to the Intergovernmental Panel on Climate Change in their Fourth Assessment Report earlier this year.

It is certainly disappointing that Al Gore's film was found by a judge to have nine errors. These were not sufficient for the court to feel that it should be withdrawn from schools nor for the Nobel Committee to decline to award its prestigious Peace prize. The judge commented that the film "is substantially founded upon scientific research and fact".

I can't help an inner sigh to think that there are still people who are so determined to stick their heads in the sand when there are such important questions which still need debating. Questions such as how we persuade our Government to stop allowing damaging projects such as new runways, new coal fired power stations and new motorways while promising to reduce our own emissions.

While I might agree with Tyce that the debate is far from over, it has moved on well beyond the exhortations of the oil companies and the Bush presidency that this is just a quaint theory of a few greens. Climate change and its cause is established fact. As parliament begins its debate over what to do about it, I invite those resistant to change to join the debate about how best we can adjust to a low carbon future.

Sam Clarke, Chairman, Stop Climate Chaos coalition