Just in case you've heard this excuse

The BBC reported on Tuesday that

[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.

In other words, the "oh, it's all natural, it's all the sun, nothing to do with us, don't worry be happy" crowd have just been shot down in flames.

"This should settle the debate," said Mike Lockwood, from the UK's Rutherford-Appleton Laboratory, who carried out the new analysis together with Claus Froehlich from the World Radiation Center in Switzerland.

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.

In other words, the mockumentary lied. It actually already had been dismantled by people who actually had some notion of what they were talking about, but this should put a stop to the nonsense.

Except it probably won't. The cosmic ray claim, in a simple form, runs like this: Cosmic rays help clouds form. But increased solar activity interferes with the amount of cosmic rays reaching the atmosphere. Thus, less cloud cover, thus, more warming. The idea is championed by Dr. Eigil Friis-Christensen of the Danish National Space Center. However, I should not only say simple form, but latest form: It is the fifth version of an argument for solar-driven global warming Friis-Christensen or a colleague has come up with over the last 16 years.

In 1991 he claimed that recent temperature variations on Earth are in "strikingly good agreement" with the length of the cycle of sunspots. In 2004 it turned out he was wrong, the result of "incorrect handling of the physical data."

He published a new paper, claiming similar results. He was wrong: There were errors in his math.

So he came up with a new idea, claiming to have discovered a remarkable agreement between solar-influenced cosmic radiation and global cloud cover. Wrong again: The satellite data he used did not measure global cloud cover.

He then, without acknowledging the previous paper was wrong, proposed there was a correlation with "low cloud cover." Again, he was wrong and no correlation could be shown.

Finally, last year his co-author on the previous paper, Henrik Svensmark, claimed to show that cosmic rays could form tiny particles in the atmosphere, particles around which molecules of water vapor could cluster, forming clouds - thus trying to reinforce the cloud cover hypothesis for global warming. Unfortunately for him, that still depends on increased solar activity, which is precisely what the new study says wasn't happening.

Bottom line:

"This paper reinforces the fact that the warming in the last 20 to 40 years can't have been caused by solar activity," said Dr Piers Forster from Leeds University, a leading contributor to this year's Intergovernmental Panel on Climate Change (IPCC) assessment of climate science.

We are the cause. We are doing it. We are causing global warming. We simply can't escape our responsibility.

Footnote: Professor Carl Wunsch of MIT has been critical of some of what he calls the "over-dramatization" of the threat of global warming, insisting that some of the predictions - such as the possibility of the ocean currents that carry warm tropical ocean water northward, moderating the climate of Europe could shut down, plunging the UK into "an ice age" - are so unlikely as to threaten the credibility of climate scientists. (Full disclosure: I have raised just that possibility, but did not predict an "ice age" but rather that London would start to experience weather more to be expected at its latitude - which is just about the same as the mouth of the St. Lawrence River. That is, much colder, but hardly an "ice age.")

He was shown making such criticisms in The Great Global Warming Swindle - and subsequently wrote that it was made to appear that he thinks

human influence must not be very important - diametrically opposite to the point I was making - which is that global warming is both real and threatening.

He called the result of the film "sad." I can think of more accurate adjectives.