SIR – Geophysicists and climatologists, who have examined in minute detail their ice-cores and done their maths, have published on the internet their findings.

They say that, as far back as they are able to go through the 4,000 million years of its existence, the temperature of the earth has been primarily at the mercy of the sun, whose output has waxed and waned many times, resulting in alternating and usually very long periods of heating and cooling.

Such researchers refer to the latest measure implemented by government planners to disconcert and control the world’s populations, by blaming human beings for the current planetary warm-up as the “great global warming scam”.

While vast sums of money are being made through so-called carbon trading, Keith Thomson’s promos for man-made global warming appear with such regularity as to make one wonder why he doesn’t read the research carried out by people renowned not for their political axe-grinding, but for their scrupulously unbiased application of scientific method.

Instead he asserts the sun’s output of heat is “at an all-time low”, the “all-time” no doubt meaning the length of time of the Earth’s existence. No reputable, objective researcher would ever make such an assertion.

Noel A Shaw, Bronte Old Road, Thornton