First, the smear term “denier” and “denial” need to be shown the door. Climate science and climate models are hardly settled for starters. And the good news is that apocalyptic predictions of anthropogenic climate change have proven exaggerated time and again. Better yet, climate sensitivity estimates have been coming down, and high-end warming estimates are looking worse by the year.

The balance of evidence (to use that famous IPCC term) is trending away from alarmism and toward what a large population of the ‘skeptics’ have been saying for years: global lukewarming.

So obviously, an important category is missing from the above five.

Enter Richard Mueller, a physicist and philosopher at the University of California at Berkeley. At the Huffington Post earlier this year, he identified six categories of scientific disagreement in “The Classifications of Climate Change Thinkers.”

They are (reproduced verbatim):

Alarmists. They pay little attention to the details of the science. They are “unconvincibles.” They say the danger is imminent, so scare tactics are both necessary and appropriate, especially to counter the deniers. They implicitly assume that all global warming and human-caused global warming are identical.

Exaggerators. They know the science but exaggerate for the public good. They feel the public doesn’t find an 0.64°C change threatening, so they have to cherry-pick and distort a little—for a good cause.

Warmists. These people stick to the science. They may not know the answer to every complaint of the skeptics, but they have grown to trust the scientists who work on the issues. They are convinced the danger is serious and imminent.

Lukewarmists. They, too, stick to the science. They recognize there is a danger but feel it is uncertain. We should do something, but it can be measured. We have time.

Skeptics. They know the science but are bothered by the exaggerators, and they point to serious flaws in the theory and data analysis. They get annoyed when the warmists ignore their complaints, many of which are valid. This group includes auditors, scientists who carefully check the analysis of others.

Deniers. They pay little attention to the details of the science. They are “unconvincibles.” They consider the alarmists’ proposals dangerous threats to our economy, so exaggerations are both necessary and appropriate to counter them.

Notice that the happy middle includes ‘global lukewarming,’ a category populated by, among others, Patrick Michaels and Chip Knappenberger at the Cato Institute’s Center for the Study of Science, not to mention Judith Curry of Georgia Institute of Technology. But there is plenty of good room for the Skeptics who are poking big holes in the claims of Warmists and Exaggerators, not to mention the Alarmists.

As I have argued elsewhere,