Letters to the Telegraph - Telegraph

Writing in support of the BBC's position on climate change, your correspondent says "the onus is on the sceptics to explain why this [increase in atmospheric CO2 levels] should not cause climate change". The answer is well known to everyone in the climate debate. The relationship between CO2 levels and the greenhouse "forcing effect" is logarithmic. It is a law of diminishing returns.

The higher the level of CO2, the less effect any further increase will have. If the current level were, say, 20 ppm, the effect of adding an extra 20 ppm would be dramatic. But at the current level of around 380 ppm, the effect of an extra 20 ppm is trivial.

I have discussed this point with scientists on the IPCC and they accept it as fact, but then they postulate complex feedback mechanisms between CO2 and water vapour to justify their alarmist position.

Roger Helmer, Blisworth, Northamptonshire

RIP Professor Marcel Leroux

In later years Professor Leroux became a prominent critic of the theory of Anthropogenic induced Global Warming (AGW). He pointed out that the evolution of Climate since the 1970s shift (when the Pacific Decadal Oscillation went into its positive phase) wasn't fitting with a simple warming trend of the planet. Among other things, deserts were expanding instead of retreating, in many places there were clear increases in atmospheric pressure and precipitation wasn't increasing. Evidence pointed to an acceleration of Meridional Circulation and not just a warming of the Atmosphere.

(Via Marc Morano)