This article appeared in Newsday Sept. 30:

The new report from the U.N. Intergovernmental Panel on Climate Change, stating that there is a 95 percent probability that human impact is the main cause of rising temperatures, has been hailed by supporters as the death blow to global-warming denial.

Unsurprisingly, skeptics remain undead, dismissing the report as politically motivated groupthink. Is this about settled science versus ideology and greed-driven obfuscation, as the editors of Popular Science magazine suggested last week when they shut down Web comments to avoid what they regard as crude attacks on scientific knowledge? Or are climate-change “true believers” trying to suppress disagreement?

My view is that human-generated warming is almost certainly real, but there remains plenty of debate on its extent, specific details and preferred solution. But my opinion, like virtually any other layperson’s, can hardly be called fully informed.

Therein lies the rub. The science of climate change and its causes is far too complex to understand without specialized training. That means the vast majority of people who voice opinions on the subject, whether professional pundits or lowly blog commenters, base those opinions at least in part on their political and ideological sympathies.

Skeptics are routinely accused of being either corporate shills or dupes of the free-market faith. (Disclosure: While I am affiliated with Reason magazine, which is partly funded by organizations accused of promoting “denialism,” I’ve never faced pressure to follow a party line.) But is everyone on the side of “settled science” disinterested? U.N. officials have an implicit interest in promoting more regulation that empowers a global bureaucracy. Many others approach environmentalism as a quasi-religious crusade; consider Al Gore’s 1992 book, “Earth in the Balance,” with its rhetoric about earth-centered spirituality and its lament about our lost “connectedness to the rest of nature.”

A few years ago, University of California at Los Angeles public policy professor Mark Kleiman, a self-identified liberal, acknowledged in a blog post that those who “dislike a social system based on high and growing consumption” and favor state regulation of markets and stronger international institutions have a powerful motive to embrace global warming as absolute truth.

While sympathetic to environmentalist causes, Kleiman noted that environmentalists often show “eagerness to believe the worst” as well an aversion to remedies that involve scientific and technological solutions–such as nuclear power–rather than drastic regulations and curbs on consumption. While Kleiman later stressed that he did not see both sides as equal offenders, his criticisms still stand.

There’s no doubt that environmental scientists have been targets of unfair attacks from the right. So-called ClimateGate–the 2009 release of hacked emails from the Climate Research Unit at the University of East Anglia–was hardly the proof of malfeasance it was made it out to be. (While critics jumped on one scientist’s mention of a “trick” to “hide the decline” in temperatures in a particular period, the reference was not to hidden data-fudging, but to an openly used adjustment technique.) But legitimate scientists who believe there remains much uncertainty about the causes and scope of climate change _ such as Judith Curry, chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, who has criticized the UN report as biased and stuck in “paradigm paralysis” _ have had their integrity unfairly questioned as well.

Much “denialism” may be rooted in scientific ignorance. Yet, as long as climate science does not distance itself from ideological zealotry and politically one-sided prescriptions, its authority will remain open to debate.