Reporting upon presidential candidate Rick Perry's skepticism about man-made global warming, the Associated Press has just published the following passage, which is now being circulated by more than a hundred news outlets that are carrying this story:

But Perry's opinion runs counter to the view held by an overwhelming majority of scientists that pollution released from the burning of fossil fuels is heating up the planet. Perry's home state of Texas releases more heat-trapping pollution carbon dioxide - the chief greenhouse gas - than any other state in the country, according to government data. 

From reading the above, one might think that very few scientists doubt the concept of manmade global warming, but this narrative is undercut by 3,805 atmospheric, earth, or environmental Ph.D. scientists who have signed a petition stating:

There is no convincing scientific evidence that human release of greenhouse gasses is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate.  Moreover, there is substantial scientific evidence that increases in atmospheric carbon dioxide produce many beneficial effects upon the natural plant and animal environments of the Earth.

As the petition's organizers point out, these are scientists "trained in specialties directly related to the physical environment of the Earth and the past and current phenomena that affect that environment." A few days ago, PolitiFact attempted to dismiss this with the wave of a hand by declaring that the "petition has been criticized for not checking the credentials of its signatories or proving that the signatories exist." However, PolitiFact does not provide a speck of evidence to substantiate this claim, which is dubious, to put it mildly. There were a few problems of mistaken identity in the past, but these have been corrected. As explained by the credentialed scientists who administer the petition: 

Petition project volunteers evaluate each signer's credentials, verify signer identities, and, if appropriate, add the signer's name to the petition list. ...

Opponents of the petition project sometimes submit forged signatures in efforts to discredit the project. Usually, these efforts are eliminated by our verification procedures. On one occasion, a forged signature appeared briefly on the signatory list. It was removed as soon as discovered.

Moreover, the website of the petition lists the names of the individuals who have signed it. Thus, if what PolitiFact says is true, these fact-checkers should be able to cite the names of some Ph.D. signatories who don't exist, or whose credentials are erroneous, or who are demanding that their names be taken off the petition. Instead, PolitiFact played the role of activists by making an unsubstantiated allegation.

Getting back to the Associated Press, twice in the paragraph above, the word "pollution" is used in reference to carbon dioxide (CO2). The trouble with this choice of verbiage is that when most people hear the word "pollution," they think of scenarios like cancerous soot billowing from smokestacks or toxic chemicals being dumped into waterways. In stark contrast, CO2 is a fundamental part of Earth's ecosystem, and natural emissions of CO2 outweigh man-made emissions by a factor of twenty to one. To cite academic literature, carbon dioxide:

• is "integral to both respiration and acid-base balance in all life,"
• is "an essential part of the fundamental biological processes of all living things," and
• "does not cause cancer, affect development or suppress the immune system in humans." 

This is hardly the kind of substance one thinks of when hearing the word "pollution." In fact, carbon dioxide is a desired output of automotive catalytic converters, which the EPA describes as an "anti-pollution device" that converts "exhaust pollutants ... to normal atmospheric gases such as nitrogen, carbon dioxide, and water." What's next, calling water a pollutant? Water vapor, by the way, contributes far more to Earth's greenhouse effect than CO2.

Journalists would likely respond that they are only following the Supreme Court's 2007 ruling (decided 5-4) that CO2 could be regulated under the pollution provision of the Clean Air Act, but these reporters are not writing for an audience of legal professionals-they are writing for the general public. Journalists are fully aware that the word "pollution" conjures up certain nasty images in the average person's mind, but yet they use it without regard for whether these images are misleading. 

Finally, when the AP reporters label Texas as the worst CO2 emitter in the nation, they omit the fact that Texas is also the second most populous state, and on a per capita basis, it is not first  but thirteenth in the nation for fossil fuel CO2 emissions.

Furthermore, certain states like California with lower CO2 emissions have quashed the development of power plants but buy a good deal of their electricity from other states that generate surpluses (such as Texas). Thus, "environmentally friendly" states are outsourcing their CO2 emissions to neighboring states as if this were the responsible thing to do. 

In this case of dueling global warming rhetoric, it is not a politician but journalists who are out on a limb scientifically. They'd do the public a service and their own credibility a favor by crawling back closer to the root of truth.

James D. Agresti is the president of Just Facts, a nonprofit institute that has just published extensive research about the issue of global warming.