This article was co-authored by E. Calvin Beisner.

Curiously, the mainstream media seem to have ignored the story, but it’s an important one. Buzzfeed reported August 7 that “YouTube Is Fighting Back Against Climate Misinformation.”

As of July 9, “YouTube is now adding fact checks to videos that question climate change … as a part of its ongoing effort to combat the rampant misinformation and conspiratorial fodder on its platform.”

But neither YouTube nor Wikipedia, the source of its “fact check,” is qualified to function as unassailable arbiter calling balls and strikes over what is or isn’t fact in any given field of human inquiry.

What YouTube is doing is a poorly disguised assault, by a politically biased organization, on the unfettered flow of intellectual debate that is essential to scientific inquiry, the discovery of truth, and the expansion of human knowledge.

YouTube’s decision might be defensible if it were evenhanded.

If, on all videos addressing climate change, from any perspective, YouTube placed a notice that climate change is the subject of vigorous ongoing debate and that equally qualified scientists hold a variety of views on the magnitude, causes, and consequences of human-induced climate change and on the best responses to it, and if it provided links to the two sites providing the most in-depth information from competing perspectives—the Intergovernmental Panel on Climate Change and the Non-governmental International Panel on Climate Change—it would be doing a real public service.

Instead, it posts its notice only on videos that challenge some part of the conventional wisdom—call it “scientific consensus,” if you like, despite the dubious claim to such. Those that embrace the conventional wisdom get a free pass.

Buzzfeed illustrates its article by a screen shot from a PragerU video of Dr. Richard Lindzen, one of the leading critics of the conventional wisdom. Shortly it quotes Anthony Leiserowitz, director of the Yale Program on Climate Change Communication, as saying YouTube’s notice “Might be confusing to some people, but that’s probably better than just accepting the denier video at face value.” The effect is to lump Lindzen in with “deniers.”

“Climate denier” is an emotionally charged term deliberately connected with “Holocaust denier.” But a legitimate disagreement arises in the proper assessment of the relative contributions made by man and nature to climate change.

The irony of applying the term to Lindzen, who is Jewish, is rich. Shame on all who diminish the six million victims of Hitler’s “final solution.”

But his Jewish faith and ethnicity aren’t the only reason calling Lindzen a “denier” is so richly and infuriatingly ironic.

Lindzen, Emeritus Professor of Atmospheric Physics and former Alfred P. Sloan Professor of Meteorology at the Massachusetts Institute of Technology, is one of the few recognized experts on cloud physics and other processes that affect weather and climate on our planet, and the accompanying changes that continually take place in the atmosphere. He has never denied human contribution to global warming—instead, he questions its magnitude and the extent to which non-human causes may contribute.

There has been an insidious effort over the past three decades to defame every scientist (I, Bill Balgord, myself have a Ph.D. in geochemistry, one of the major pillars that contribute to an understanding of climate science) who deigns to disagree with the conventional wisdom.

There’s another irony in YouTube’s action. The notice it posts on PragerU’s video says, “Global warming, also referred to as climate change, is the observed century-scale rise in the average temperature of the Earth’s climate system and its related effects. Multiple lines of scientific evidence show that the climate system is warming.”

What’s ironic about that? It’s meant to correct Lindzen. Yet Lindzen would affirm it—and has done so repeatedly throughout his illustrious career.

Indeed, any respectable scientist will agree that climate changes. It always has changed and always will. But equating healthy skepticism over the magnitude of the contribution by human beings with an out-and-out denial of the facts is a bold-faced fallacy and loathsome ad hominem attack.

Contrary to popular understanding, the primary reason offered by members of the climate-change establishment for asserting that man is the major contributor to an allegedly rapid and dangerous rise in global temperature is not empirical observation—the gold standard of scientific inquiry—but the erratic projections from climate models that they themselves have constructed.

This is a prime example of circular reasoning, pure and simple. But they have succeeded in convincing many people that their computers are correct and that Earth is headed for a cataclysmic rise in temperature with all the usual advertised consequences.

The rapid—1°C in thirty years—rise in global temperature predicted by James Hansen, et al., in 1988, on the basis of computer climate models, has not happened.

Hansen offered three scenarios:

1. “Business as usual,” with rapidly rising carbon dioxide emissions, which would bring that 1°—which would have entailed an average of 0.33° of warming per decade.
2. “Most plausible,” with emissions remaining constant at 1988 levels, which would make the world 0.7° warmer today—which would have required 0.23° of warming per decade.
3. “Highly unlikely,” with emissions rising from 1988 to 2000 and then stabilizing, which would make the world about 0.3° warmer today—which would have required 0.1° of warming per decade.

By and large, the United Nations Intergovernmental Panel on Climate Change embraced Hansen’s scenarios.

So, how did Hansen, the high priest of global warming fears, and his acolytes do?

As data collected by sensors aboard NASA satellites show, the world today is, on average, 0.3° warmer than when Hansen set forth his scenarios. Warming has progressed at only 0.13° per decade. In short, for temperature, Hansen’s third scenario, which he called least likely, has occurred.

But this warming didn’t occur because CO₂ emissions flattened in 2000, as Hansen said would be necessary for that temperature scenario. No, they kept right on rising. What continued to occur was pretty much the condition he said would bring on his first temperature scenario.

From that it follows that Hansen’s understanding of what drives global average temperature— carbon dioxide—was, and remains, wrong. And the same goes for the understanding of everyone who agreed with him.

The left routinely uses its considerable resources to silence critics. I further assert that they realize that in many instances they possess a weak argument or none at all and their best tactic is to launch ad hominem attacks or unilateral denial of access to the public square. The LA Times did just that several years ago when it began refusing to publish any contrarian letters to the editor or opinion columns.

For years now any expert or layperson who voices a scintilla of doubt regarding the certainty of catastrophic anthropogenic climate change (aka, global warming) has instantly been demonized in the mainstream media as a pariah or a “climate denier.” That tactic is itself a lie, because as already explained, climate skeptics emphatically do believe climate changes. We also think human contribution is smaller, and less dangerous, than alarmists claim, and we think Mother Nature is fully capable on her own of generating observed climate changes.

This article was originally published on Townhall.com.