[Editor note: Marlo Lewis’s extensive rebuttal to Scientific American writer David Appell in the comments section to yesterday’s post (Andrew Dessler Challenges Rick Perry: How Should Perry Respond?) is presented as a full post today.]

Yesterday, Rob Bradley excerpted portions of a post I wrote last Friday on whether Gov. Rick Perry’s remarks about global warming at the GOP candidates forum in California were “anti-science.” My objective was to immunize the candidates — and the public generally — against a rhetorical trick that Al Gore and other alarmists have been using to great effect for years.

Alarmists would have us believe that all they have to do is establish that greenhouse gas emissions are warming the planet, and then everything else they say follows as night follows day. If mankind is mainly or even partly responsible for the warmth of recent decades, then, supposedly, we are in the midst of a “planetary emergency” that “threatens the survival of civilization and the habitability of the Earth” (Al Gore’s phrase).…

“As I have argued for years, we simply do not know the answer [to the sensitivity of climate to greenhouse gas forcing]. There is a wide margin of error in many of the ingredients that go into the [climate] models. For example, we do not know some of the radiative properties of the aerosols to a factor of 5. No matter how good your climate model is, you cannot compensate for that uncertainty. The range of uncertainty is broad enough to accommodate [Patrick] Michaels (well, maybe North) and [Jerry] Mahlman.”

– Gerald North (Texas A&M) to Rob Bradley (Enron), September 17, 1999

“One has to fill in what goes on between 5 km and the surface. The standard way is through atmospheric models. I cannot make a better excuse.”

– Gerald North (Texas A&M) to Rob Bradley (Enron), October 2, 1998

“We do not know much about modeling climate.

[The other parts of this series on the activism of Texas A&M climatologists are here: Part I, Part II, and Part III]

“If the models are as flawed as critics say … you have to ask yourself, ‘How come they work?'”

– Gavin Schmidt [NASA], quoted in David Fahrenhold, “Scientists’ Use of Computer Models to Predict Climate Change is Under Attack,” Washington Post, April 6, 2010.

“We do not know much about modeling climate. It is as though we are modeling a human being. Models are in position at last to tell us the creature has two arms and two legs, but we are being asked to cure cancer.”

     – Gerald North (Texas A&M) to Rob Bradley (Enron), November 12, 1999

A Washington Post piece last week, “Scientists’ use of computer models to predict climate change is under attack,” has brought attention to the importance of climate modeling in the current debate over climate sensitivity to greenhouse gases (GHGs).…

[The other parts of this series on the activism of Texas A&M climatologists are here: Part I, Part III, Part IV, and Part V]

“Texas’ challenge to the EPA’s endangerment finding on carbon dioxide contains very little science….”

– Andrew Dessler, Gerald North, et al….., “On Global Warming, the Science Is Solid,” Houston Chronicle, March 7, 2010. [Also see yesterday’s Part I post on Dessler/North.]

Last month, the State of Texas filed a petition for reconsideration in the U.S. Court of Appeals for the D.C. Circuit (summary here) against the U.S. Environmental Protection Agency (EPA). The Petition lays out why the EPA’s reliance on the Intergovernmental Panel on Climate Change (IPCC) to provide an assessment of climate change science was a very bad idea.…