How the Bogus ‘ClimateGate’ Turned a Scientist Into a Climate Denier

The “scandal” that allegedly fueled a once-respected academic’s descent into climate denialism was still further debunked years after his passing.

Hal Lewis, an emeritus professor of physics at the University of California-Santa Barbara, announced his resignation from the American Physical Society (APS), on October 6 2010 in a letter to then-president Curtis Callan that soon circulated online in climate denial circles after he accused the group of being influenced by a “money flood”:

It is of course, the global warming scam, with the (literally) trillions of dollars driving it, that has corrupted so many scientists, and has carried APS before it like a rogue wave. It is the greatest and most successful pseudoscientific fraud I have seen in my long life as a physicist.

Lewis also made reference in the letter to “ClimateGate” — the nickname for a cyber attack against the Climatic Research Unit (CRU) at the University of East Anglia in England that deniers claimed exposed that the scientific community had manipulated data to exagerate the effects of global warming.

More than a thousand emails — most of them from CRU head Phil Jones — were stolen in the attack along with around 2,000 documents.

“In the interim the ClimateGate scandal broke into the news, and the machinations of the principal alarmists were revealed to the world,” Lewis wrote. “It was a fraud on a scale I have never seen, and I lack the words to describe its enormity. Effect on the APS position: none. None at all. This is not science; other forces are at work.”

As the New York Times reported, however, Lewis’ letter represented an abrupt about-face on his own statements regarding climate change in the 1990 book Technological Risk:

All models agree that the net effect will be a general and global warming of the earth; they only disagree about how much. None suggest that it will be a minor effect, to be ignored while we go about our business.


The bottom line is that the Earth will be substantially warmed by the accumulation of man-made gases, mainly carbon dioxide, and that warming could conceivably approximate the climate at the time of the dinosaurs. It seems likely, but not certain, that sea level will rise accordingly, conceivably by several feet or more. We are doing this to ourselves.

Can anything be done to slow it down? The only option in the long run is to decrease the amount of waste gases deposited in the atmosphere.

The APS rejected Lewis’ accusations in a statement, saying:

On the matter of global climate change, APS notes that virtually all reputable scientists agree with the following observations: carbon dioxide is increasing in the atmosphere due to human activity; carbon dioxide is an excellent infrared absorber, and therefore, its increasing presence in the atmosphere contributes to global warming.

The group also noted that Fox News commentator Laura Ingraham falsely identified Callan as the member who had resigned; in January 2011, the APS said in response to a letter:

Not only did Fox News not clarify her position, they have been unwilling to discuss any attempt to correct the facts, despite much effort by APS to do so. And not only did they air Ingraham’s report (or “commentary”), they also simultaneously displayed a picture of Curtis Callan, thereby compounding the error and assuming at least some complicity in promulgating erroneous information.

Time and various climate-related emergencies have only further highlighted the extent of Lewis’ disinformation, even before his death in March 2011. But the BBC reported in November 2021 that Steve Mosher, the man who received a copy of the original stolen CRU material, finally admitted that he had been the one who had actually manipulated the data:

US-based Mr Mosher, a key figure in the scandal, and other climate change sceptics were sent thousands of emails, documents and scientific data stolen from the CRU, which is based in Norwich.

He selected emails he thought would be most damaging, and these were then promoted on climate sceptics’ blogs.

“In the end, when I checked my results, and my results matched Phil Jones’ results — the guy who I had criticised all those years — and then I had to eat this giant irony sandwich,” Mosher said. “And damn near broke my teeth.”

Update 7/18/2022, 3:43 p.m. PST: This article has been revamped and updated. You can review the original here. — ag