A new scientific study concludes that changes in the Sun's output cannot be causing modern-day climate change.
It shows that for the last 20 years, the Sun's output has declined, yet temperatures on Earth have risen.
It also shows that modern temperatures are not determined by the Sun's effect on cosmic rays, as has been claimed.
Which leaves us in something of a quandry really, because how else are we to explain the solar system-wide warming that we have observed?
Global warming on Neptune’s moon Triton as well as Jupiter and Pluto, and now Mars has some scratching their heads over what could possibly be in common with the warming of all these planets.
Are we so powerful that our pollution is warming these other celestial bodies too? I doubt it.
Dr Lockwood initiated the study partially in response to the TV documentary The Great Global Warming Swindle, broadcast on Britain's Channel Four earlier this year, which featured the cosmic ray hypothesis.
"All the graphs they showed stopped in about 1980, and I knew why, because things diverged after that," he told the BBC News website.
"You can't just ignore bits of data that you don't like," he said.
Oh, I quite agree, Dr Lockwood. So would you mind telling us why the IPCC did not bother to include the Briffa data showing that the divergence of tree rings (one of the IPCC's crucial proxies in divining past temperatures) from the known recent temperature record? Or the appalling inaccuracies inherent in the measurement and placement of current temperature monitoring stations?
[The IPCC] was criticised in some quarters for not taking into account the cosmic ray hypothesis, developed among others by Henrik Svensmark and Eigil Friis-Christensen of the Danish National Space Center.
Their theory holds that cosmic rays help clouds to form by providing tiny particles around which water vapour can condense. Overall, clouds cool the Earth.
During periods of active solar activity, cosmic rays are partially blocked by the Sun's more intense magnetic field. Cloud formation diminishes, and the Earth warms.
Mike Lockwood's analysis appears to have put a large, probably fatal nail in this intriguing and elegant hypothesis.
But the problem is, you see, that their's was but one hypothesis. They maintained that increased cloud formation reduced heating of the earth by reflecting radiation back into space. But there is another theory.
What Dr Lockwood is saying is that, since the mid-1980s, solar output has declined and we would then expect to see more clouds forming and thus the temperature of the planet should fall as the sun's radiation is reflected back into space. However, what we have seen is rising temperatures, combined with a declining solar output.
But, what is clouds did not work in the way that Henrik Svensmark and Eigil Friis-Christensen say that they do, i.e. they do not cause cooling?
It is generally accepted that water vapour in the air, not least in the form of clouds, is responsible for by far the largest part of the so-called Greenhouse effect. If you think about it logically, this seems obvious—think of a muggy day: it is always cloudy. Equally, a cloudless night leads to very low temperatures.
The simple conclusion? Yes, the Greenhouse effect that clouds have is far greater than any reflective properties. So, actually, with reduced solar output we should see more cloud formation and rising temperatures. Which is, of course, precisely what this report has shown to be happening.
The Englishman has some more on this and links to the relevent papers.
Strangely it seems very easy to find graphs on line which claim to show the continued influence of cosmic rays on climate—for example Cosmic Rays and Climate Change, though I'm sure they haven't ignored this data. After much searching, as the BBC doesn't seem to believe in linking to the real research, here is their paper [PDF]. Fighting talk - and there seems to be counter arguments in place already, but I look forward to a detailed response.
"This should settle the debate," says Mike Lockwood: indeed it does, Mike; indeed it does.
The sun is causing the lion's share of global warming.