IN reply to Stuart Chapman’s recent letter on the subject of global warming, I would like to make the following observations.

You say the correlation between climate and CO2 levels is not good. Not so. Although global temperatures can change without significant changes in CO2 levels, records from ice cores show that changes in CO2 levels cannot take place without significantly affecting global temperatures.

Current CO2 levels now exceed measurements over the past halfmillion years and are rising faster than previously recorded.

You appear to deny even that global warming is occurring at all. How else do you explain the fact that all the world’s glaciers are shrinking and some will soon disappear altogether? The Greenland ice sheet is getting thinner year by year and every summer there is more open water in the Arctic Ocean, much to the displeasure of the polar bears.

Furthermore, all our oceanographers agree that the waters around Britain are getting warmer, so that the plankton are moving north by as much as 1,000km, followed by the fish that feed on them, ie cod and haddock.

Other species not normally seen in our waters, such as spider crabs, are being seen with increasing regularity.

Yes, Mr Chapman, global warming is a fact.

Carbon is constantly being exchanged between the atmosphere, the oceans and the soil as a result of physical and biological processes and is very well balanced, so the level of CO2 would remain stable without human interference.

The most direct human influence in increasing atmospheric CO2 levels is through the burning of fossil fuels, but further increases are caused by deforestation and use of land for agriculture, both of which reduce the ability of the ecosystem to absorb CO2, so that more CO2 remains in the atmosphere.

It is true that human emissions are small compared to natural emissions but, as I have said, natural emissions and absorption are well in balance.

Other factors, such as solar activity or variations in the Earth’s orbit can affect climate, but CO2 level is by far the most important factor. Since the industrial revolution, the CO2 level in the atmosphere has increased from 280ppm to 397ppm, a considerable increase and all due to man’s activities.

Emissions from volcanoes, incidentally, are about one per cent.

In conclusion, Mr Chapman, I would appreciate it if you did not presume to give me any further lessons in science, or refer to me as stupid, along with the great majority of climatologists, as there is an overwhelming acceptance among them that manmade global warming is a fact. Otherwise I may be forced to refer to you and your views in similarly unflattering terms.

David James Bolton