By Roger Highfield | telegraph.co.uk

A new study further enforces the view that the sun is not responsible for recent climate change

The strongest evidence to date that the sun is not responsible for recent global warming has been set out by scientists.

The new study by Prof Michael Lockwood of the Rutherford Appleton Laboratory, near Oxfordshire, and Claus Fröhlich of the World Radiation Center in Davos, Switzerland, overturns claims by climate sceptics who say that the planet's climate has long fluctuated and that current warming is just part of that natural cycle - the result of variation in the sun's output and not greenhouse gas emissions. Their study appears in the Proceedings of the Royal Society A.

The study found that global warming since 1985 has been caused neither by an increase in solar radiation nor by a decrease in the flux of galactic cosmic rays.

Some researchers had also suggested that the latter might influence global warming because the rays trigger cloud formation.

Prof Lockwood said that the comprehensive study was a response to misleading media reports. He cited 'The Great Global Warming Swindle', a television programme shown in March by Channel 4, as a prime example.

"All the graphs they showed stopped in about 1980, and I knew why, because things diverged afterwards. You can't just ignore bits of data that you don't like," he said. "The key point of our paper is that since 1985 all the possible solar influences have been in the wrong direction to give warming," said Prof Lockwood.

Although some have tried to counter this by arguing that the response of the Earth's climate system lags behind changes in the sun, Prof Lockwood added that the only way for this to work would be by invoking a very large response lag of the order of 50 years which would overturn previous ideas of how the Sun influences the Earth.

"This paper is the final nail in the coffin for people who would like to make the sun responsible for present global warming," Stefan Rahmstorf, a climate scientist at the Potsdam Institute for Climate Impact Research in Germany, told the journal Nature.

The new study compiled solar data for the past 100 years. The two researchers averaged out the 11-year solar cycles and looked for correlation between solar variation and global mean temperatures. Solar activity peaked between 1985 and 1987.

But mainstream scientists agree that the sun does have some influence on fluctuations in the Earth's temperature. As Prof Lockwood said: " I do firmly believe that there is a solar influence on pre-industrial climate and that may well have extended into the last century - up to about 1940 - but our results confirm that recent climate change is not caused by the sun. We do this with a simple and direct analysis of data and not using climate computer models - which are often a cause of scepticism."

A spokesman for the Royal Society said: "This is an important contribution to the scientific debate on climate change. At present there is a small minority which is seeking to deliberately confuse the public on the causes of climate change. They are often misrepresenting the science, when the reality is that the evidence is getting stronger every day. We have reached a point where a failure to take action to reduce carbon dioxide and other greenhouse gas emissions would be irresponsible and dangerous."

Article from: http://www.telegraph.co.uk/earth/main.jhtml
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The Great Global Warming Swindle