Last August, I was all over Bill Gates, praising him for his investment in a new generation of nuclear power stations. However, he has now well and truly blotted his copybook by giving his name, and his dollars, to a group of scientists who are involved in pushing the claims for geo-engineering.

They argue that as plan A, an international political agreement to reduce the amount of CO2 in the atmosphere, is unlikely to succeed, then we need a plan B.

As they expect the global temperature to rise by about two degrees this century, they suggest that the only alternative is to turn down the solar thermostat, that is cut out some of the heating that we depend on from the sun. That would keep the temperature around the level that it is now, but there would still be all the fossil fuel pollutants in the atmosphere.

These scientists take their cue from the natural world, and particularly from large volcanic eruptions. We all remember the effect of the dust and ash clouds in 2010 following the Iceland volcanic eruption, and world-wide there have been 75 larger events since 1900. We’re not short of evidence about the way that they reduce global temperature.

In 1815, an Indonesian volcano, Tabora, produced the largest eruption for a thousand years, and the dust and sulphur dioxide stayed in the atmosphere for more than three years.

The next year, 1816, was known as the year without a summer when crops failed and thousands died in Europe and the United States. The marvellous sunsets of the time were captured in Turner‘s paintings. More recently Mt Pinatubo erupted in 1991 with the result that 1992 was the coolest year of the last 30.

So adding sulphur dioxide to the atmosphere certainly works, and Bill Gates’s friends are researching how they can put five million tonnes of it as high as 100,000ft in the stratosphere, at the edge of space.

It would take more than £500 billion to fire 70 million shells from 16in naval guns to get the sulphur dioxide high enough. This is clearly nonsense – a waste of money and a very dangerous way to behave.

The climate would be changed, unexpected droughts and storms would occur, and the world would be mired in famines, legal challenges and international discord.

The answer, surely, is to concentrate on developing energy sources that don’t produce carbon dioxide in the first place, and the technologies are already well- established – nuclear and solar power, backed up by wind and waves will do the trick.

We have damaged the planet enough without even trying, so we must not set out to do it on purpose.