RealClimate has an excellent post (here) on the Cato Institute’s efforts to get signatories for its new global warming denial ad. But they missed one especially ironic point — a key study Cato uses to argue we may see much less warming than the models predict comes to exactly the opposite conclusion.

The Cato Institute is a libertarian think tank that has long been a bastion of anti-scientific denial (see “The intellectual bankruptcy of the Cato Institute“). The new ad (here [PDF]) attacks President Obama directly. First, it quotes his November 19, 2008 statement:

“Few challenges facing America and the world are more urgent than combating climate change. The science is beyond dispute and the facts are clear.”

Then in big bold letters it says:

With all due respect
Mr. President,that is not true.

Then it launches into its diatribe of disinformation:

We, the undersigned scientists, maintain that the case for alarm regarding climate change is grossly overstated. Surface temperature changes over the past century have been episodic and modest and there has been no net global warming for over a decade now.[1,2] After controlling for population growth and property values, there has been no increase in damages from severe weather-related events.[3] The computer models forecasting rapid temperature change abjectly fail to explain recent climate behavior.[4] Mr. President, your characterization of the scientific facts regarding climate change and the degree of certainty informing the scientific debate is simply incorrect.

RealClimate does an excellent job of debunking all of these points, explaining “Of these papers, not one has the evidence to support the statements attributed to them in the main text.”

I am not going to repeat all of that debunking. I will note that using the NASA Goddard Institute for Space Studies temperature data set (which is almost certainly a more accurate representation of actual global temperatures than Hadley’s, see “What exactly is polar amplification and why does it matter?“), 2005 was the warmest year on record. And even using Hadley’s data the “2000s are easily the hottest decade in recorded history.”

[As a related aside: While the recent La Niña and solar minimum have no doubt had a modest impact in slowing the temperature rise, I suspect one of the reasons the temperature record doesn't show much warming since 2005 is that we simply lack the temperature stations in the Arctic needed to reveal the hyper-warming there.] And I will note that footnote #3 is of course our old friend Roger Pielke, Jr. What a shock that his work would appear in a global warming denier ad. Or that the scientific literature suggests he is wrong (see Pielke in Nature: “Clearly, since 1970 climate change … has shaped the disaster loss record.”) Still, this ad shows once again that deniers try to shout down any talk of a link between climate change and extreme weather.

But what is most amusing is footnote #1, Swanson and Tsonis [PDF] (GRL, 2009). RealClimate notes

The use of the recent Swanson and Tsonis paper is simply opportunism. Those authors specifically state that their results are not in any way contradictory with the idea of a long term global warming trend. Instead they are attempting to characterise the internal variability that everyone knows exists.

But we can go further.

This paper, “Has the climate recently shifted?” has become a favorite of deniers because it offers a theory that says the recent apparent flattening in temperature rise (which, as I have said, is more apparent than real) could last for decades:

… the new global mean temperature trend may persist for several decades

The deniers, however, never bother reading the entire conclusion. The very next line says :

Of course, it is purely speculative to presume that the global mean temperature will remain near current levels for such an extended period of time.

And it gets better. Even if you buy into their purely speculative theory, it offers no respite from global warming — quite the reverse, as the final sentence from the paper’s conclusion makes clear:

If the role of internal variability in the climate system is as large as this analysis would seem to suggest, warming over the 21st century may well be larger than that predicted by the current generation of models, given the propensity of those models to underestimate climate internal variability.

Now that would be particularly bad news since, as of its publication date, the current generation of models is predicting tremendous warming this century:

In other words, the key footnote that Cato has cited suggests warming this century may exceed 5-7°C warming.

The paper’s author, Swanson, has said:

When the climate kicks back out of this state, we’ll have explosive warming.

And that is precisely the same conclusion as recent studies in Science and Nature, although the authors of those papers argue that explosive warming is going to happen much sooner (and the media and the deniers were confused about that, too):

Over the next decade, the reality that we are facing catastrophic global warming will become painfully obvious to the vast majority of people — rendering deniers like Patrick Michaels of Cato the laughingstocks they should already be.

For more background on Cato’s Climate ad campaign, see DotEarth.

This post was created for, a project of the Center for American Progress Action Fund.