During this week’s GOP presidential candidates debate in California, Texas Gov. Rick Perry made a statement about global warming that Mother Jones, the Huffington Post, the UK Guardian, and others condemn as “anti-science.” Asked by moderator John Harris of Politico “which scientists” are “most credible” in questioning “the idea that human activity is behind climate change,” Perry replied:

Well, I do agree that there is – the science is – is not settled on this. The idea that we would put Americans’ economy at – at- at jeopardy based on scientific theory that’s not settled yet, to me, is just – is nonsense. I mean, it – I mean – and I tell somebody, I said, just because you have a group of scientists that have stood up and said here is the fact, Galileo got outvoted for a spell. But the fact is, to put America’s economic future in jeopardy, asking us to cut back in areas that would have monstrous economic impact on this country is not good economics and I will suggest to you is not necessarily good science. Find out what the science truly is before you start putting the American economy in jeopardy.

The UK Guardian was quick to denigrate Perry’s answer:

It’s one thing to question the economic impact and legacy of current climate policy proposals – you would expect and wish for politicians to debate this – but for a politician to question the science in this way is striking. . . .Note how he studiously ignored the moderator’s well-crafted question: who exactly are these “Galileos” that you believe have so comprehensively cast doubt on the canon of climate science? Perry couldn’t – or wouldn’t – name them.

The Guardian makes a mountain out of a molehill. If Harris was so keen to know which climate scientists Perry finds most credible, he could have just restated the question. Perry was apparently more interested in making two basic points: (1) he does not view global warming as a warrant for imposing massive new regulatory burdens on the U.S. economy; (2) he is not impressed by appeals to an alleged “scientific consensus” because, after all, scientific issues not settled by counting heads.

The question Harris asked is bound to come up again and again in candidate forums, and it’s a bit of a loaded question at that. Alarmists would like us to believe that any human contribution to climate change constitutes a “planetary emergency” (Al Gore’s phrase) and, as such, justifies the imposition of cap-and-trade and other assaults on affordable energy. Hence, they would like nothing better than to trick opponents into arguing as if the case against cap-and-trade, or against EPA’s hijacking of climate policy, hinges on the implausible thesis that greenhouse gases do not have a greenhouse (warming) effect.

How then should presidential contenders respond to such questions?

Here’s how I would answer Harris’s question:

The premise of your question, If I’m not mistaken, is the notion, popularized by Al Gore, that any human contribution to climate change by definition constitutes a “planetary emergency” demanding urgent regulatory action. This is ideology, not science. The key scientific issue is not whether greenhouse gas emissions have a greenhouse effect but how sensitive Earth’s climate is to the ongoing rise in greenhouse gas concentrations. The sensitivity issue is far from being “settled.” You asked for names of credible scientists. Three who raise fundamental questions about the sensitivity assumptions driving the big, scary global warming forecasts are Richard Lindzen, Patrick Michaels, and Roy Spencer. The debate on climate sensitivity will likely be with us for some time. At this point, all I can say is that those who assume a highly sensitive climate have a hard time explaining why there’s been no net global warming over the past 14 years.

Much of what we hear about global warming is hype and scaremongering. If climate change is the dire peril some people claim it is, then why has there been no acceleration in sea-level rise over the past five decades? Why did heat-related mortality in the USA decline, decade-by-decade, from the mid-1960s to the late 1990s? Why has there been no long-term increase in hurricane-related economic damages once you adjust for increases in wealth, the consumer price index, and population? Why have total deaths and death rates related to extreme weather events declined by 93% and 98%, respectively, since the 1920s? Why has U.S. farm output increased dramatically over the past half century?

For more than two decades, the environmental movement has been pushing an ideology that might be called Kyotoism or, alternatively, Gorethodoxy. This is the view that global warming is a catastrophe in the making from which we can save ourselves only by waging the moral equivalent of war on affordable energy. The real catastrophe would be in enacting their agenda of cap-and-trade, energy taxes, and more subsidies for companies like Solyndra. Not even a prosperous America could afford to replace coal, oil, and natural gas with wind turbines, solar panels, and biofuel. We certainly cannot afford to do so in the current economic crisis.

UPDATE (September 14, 2011): 

On Monday, prolific energy scholar Rob Bradley excerpted most of my blog post at Masterresource.Org in a column titled “Andrew Dressler Challenges Rick Perry: How Should Perry Respond?” Dressler is a climatologist at Texas A&M. 

Science writer David Appell posted a comment on Bradley’s column, asserting: “It’s easy to refute Lewis.” So on Tuesday, I posted a column at Masterresource.Org responding to Appell’s comment. The column fleshes out the argument I presented above, in sound bite-sized chunks, at Globalwarming.Org.

I am happy to report that MIT physicist Richard Lindzen sent me an email outlining how he would discuss climate science within the space of a sound bite. I reproduce Dr. Lindzen’s comment below with his permission:

Virtually all scientists working on climate do agree that there has been a fraction of a degree of warming since the middle of the 19th century, that CO2 has been increasing, and that this should contribute something to the warming. However, the crucial question is whether the contribution is large enough to be of concern, and even the presidents of the National Academy of Sciences and the Royal Society agree that this is still unknown. Indeed, even if the increase in CO2 accounted for all of the observed warming, it would not imply a dangerous sensitivity. If the models on which alarm is based are correct then man has contributed several times more warming than has been observed. Modelers skirt this issue by claiming that aerosols have hidden the difference, but this is simply the invocation of fudge factor since the aerosol impact is unknown, and each model chooses a different value.