I WAS disturbed to read the letter from K N (May 1) about global warming.

At first glance it appears a reasonable argument; however K N is misinformed and the message is a dangerous one, because global warming as a man-made phenomenon is now recognised as fact.

Although there is a natural element of warming, the rate of climate change we are experiencing is directly linked to the input of heat-absorbing carbon dioxide into the atmosphere and this is no longer debatable.

Evidence from studying polar ice cores shows that over the several hundred thousand years covered by the ice record, temperature changes were primarily driven by changes in the Earth's orbit around the sun.

Over this period, changes in temperature did drive changes in carbon dioxide (CO2). However, concentrations of CO2 are now much higher and increasing much faster than at any time in at least the last 600,000 years. This should be a warning that what is happening now is very different to what happened in the past.

Climate change myths are dispelled comprehensively by the Met Office chief scientist at www.metoffice.gov.uk/research/hadleycentre/ and the UK Climate Impacts Programme at www.UKCIP.org.uk It is so important that we accept that we have caused this change in the earth's climate, and that the effects will become more pronounced as time goes on. There's no point burying our heads in the sand - we have the power to change the CO2 trend and make a difference to the climate we leave for future generations, and it is our responsibility to do so, before it is too late.

N HORTER, Bitterne Park, Southampton.