Scientists have debunked the claim, much touted by rightwing denialists, that the sun rather than human action is the cause of the current period of global warming.
Claims in a controversial Channel 4 programme that recent rises in global temperatures have been caused by the sun have been disproved by scientists. The programme, the Great Global Warming Swindle, claimed that instead of greenhouse gases from human activity being to blame for a recent surge in temperatures, a change in solar activity was responsible because it influenced the number of cosmic rays that strike the Earth.I wrote about the way in which some of the scientists interviewed by the agenda-driven makers of the documentary said they had been duped into participating and then misquoted back in March.
...But the new analysis, to be published in a Royal Society journal on Tuesday, shows that global warming since 1985 cannot have been caused by an increase in solar radiation or by a decrease in cosmic rays.
Mike Lockwood, a physicist at the Rutherford Appleton Laboratory in the UK, said: "It is absolutely clear that the sun is nothing to do with the recent warming.
"This doesn't rely on models, it uses real data and it shows that all the solar trends have been going in the opposite direction for the last 20 years."
Professor Lockwood carried out the new study to directly challenge the claims made in the Channel 4 programme, which was criticised as misleading by scientists.
With Claus Frohlich of the World Radiation Centre in Davos, Switzerland, he compared temperature and solar data for the past 100 years.
The records show that solar activity peaked between 1985 and 1987.
Since then, trends in sunshine, sunspot number and cosmic rays have all been in the opposite direction to that required to explain global warming - while temperatures at the Earth's surface rose steadily by more than 0.3C.
The two scientists conclude: "Our results show that the observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever mechanism is invoked."
In pre-industrial times, Prof Lockwood said, there was considerable evidence that the sun played a significant role in driving global climate, but he was concerned this genuine area of study had been done a "great disservice" by climate sceptics who were trying to confuse people about recent global warming.
He said: "I know we're attacking a bit of a strawman here because there is no serious scientific debate about recent warming, but those who disagree are very vocal. We wrote this up specifically to show they are wrong, and wrong in a dangerous way."
Prof. Lockwood may well be right that "there is no serious scientific debate about recent warming" but the 26%ers aren't interested in serious science, they play serious politics with every lie and dirty trick that comes to hand. Even after this, expect wingnut pundits to continue citing The Great Global Warming Swindle as if it were a credible part of the scientific debate.