Climate change ‘not due to the sun'

Key argument of sceptics shot down by new study

Global warming is happening despite – not because of – solar cycles. That’s the conclusion of an extensive new study published by the Royal Society, the UK’s leading scientific academy. This effectively nails one of the last remaining arguments of the ‘climate sceptics’, who deny that rising greenhouse gas emissions due to human activities are causing climate change.

The sceptics have argued that natural surges in solar activity – ‘solar forcings’ – are the principal cause of recent warming. This argument featured heavily on Channel Four’s controversial documentary, The Great Global Warming Swindle.

But the new study, led by Professor Mike Lockwood of the Rutherford Appleton Laboratory, Oxford,and Southampton University, finds no evidence to support this claim. It analysed a whole range of data on solar activity during 1975-2000, and compared this with global temperatures over the same period. Crucially, it discovered that while the sun’s activity has been decreasing since 1985, temperatures have continued to rise – and at an increasing rate.

While solar activity may have helped boost warming in the first half of the 20th century, says the study, it has clearly not done so in recent times. “The temperature record is simply not consistent with any of the solar forcings that people are talking about,” said Lockwood. “They changed direction in 1985, the climate did not... the increase should be slowing down, but in fact it is speeding up.”

The study also analysed and dismissed claims that a ‘time lag’ between solar activity and its impact on temperatures could explain the discrepancy.

A spokesman for the Royal Society commented: “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.” – Martin Wright

 

19 September 2007

Martin Wright

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