Various news sources had a heyday when Secretary of State John Kerry made comments July 22 about HFCs (hydrofluorocarbons), the chemicals used in many air conditioners and refrigerators around the world, calling them a major risk because they promote global warming.

Conservative media tended to trumpet the news as one more instance of a patently absurd statement by the Secretary of State. Fox News headlined its story, “Kerry: Air conditioners as big a threat as ISIS.” Washington Examiner‘s headline was, “Kerry: Refrigerator chemicals are just as bad as ISIS.”

Similar headlines propagated quickly, and someone started a petition at Change.org to remove air conditioning from all U.S. State Department property.

Mainstream media tended to ignore it.

So what did Kerry really say? What were its implications? And how does what he said stand up to critical examination?

Addressing a meeting in Vienna to amend the 1987 Montreal Protocol, which banned the use of chlorofluorocarbons (CFC’s, alleged to threaten the stratospheric ozone layer) but resulted in their widespread replacement with HFCs, Kerry said:

[On Thursday], I met in Washington with 45 nations—defense ministers and foreign ministers—as we were working together on the challenge of [ISIS] and terrorism. It’s hard for some people to grasp it, but what we—you—are doing right now is of equal importance because it has the ability to literally save life on the planet itself. … The use of hydrofluorocarbons is unfortunately growing. Already, the HFCs use[d] in refrigerators, air conditioners, and other items are emitting an entire gigaton of carbon dioxide annually. Now, if that sounds like a lot, my friends, it’s because it is. It’s the equivalent to emissions from nearly 300 coal-fired power plants every single year.

So, did he explicitly say HFCs are as dangerous as ISIS? No. But he did say that what the gathering to amend the Montreal Protocol was doing was “of equal importance” as “the challenge of [ISIS].” That’s pretty nearly the same thing.

But Gersh Kuntzman, writing in The New York Daily News in a story headlined “No, John Kerry did not say refrigerators bad as ISIS,” tried to debunk that.

To my ears, Kerry said that fighting terror is very important, which is why he met with those 45 international leaders. But he also said fighting global warming and the demise of the ozone layer is also important. …

So let’s all just take a breath while we still can: John Kerry did not say that air conditioners were more dangerous than ISIS. He said that ISIS represents a global terror challenge that must be solved (true) and he said that chemicals that destroy the ozone layer and cause global warming must be phased out so we don’t destroy life on this planet (which is also true).

That’s a plausible, if not very persuasive, interpretation of Kerry’s statement. But ironically Kuntzman went on to say what amounts to pretty much what he said Kerry didn’t say:

So far, ISIS has killed tens of thousands of people around the world. That’s certainly bad, but it would not end civilization. But global warming has the potential to kill millions and displace billions living in mostly impoverished coastal areas. That could disrupt civilization to the point of no return. …

ISIS doesn’t have the power to make human beings extinct — indeed, by definition, if 30,000 ISIS troops were to somehow triumph over the 7 billion or so humans committed to modern civilization, at least there would humans still roving the planet.

But if global warming were to win, that’s it. We’re done.

That sure sounds like Kuntzman thinks global warming is a much bigger threat than ISIS—and if he thinks HFCs are driving that global warming, then they must be more dangerous than ISIS, too.

But is Kuntzman right? What’s the risk from HFCs’ impact on global warming?

First, compare the CO2-equivalence of HFCs to total natural and human CO2 emissions. Human emissions, almost entirely from fossil fuel burning and land use, amount to about 29 gigatons per year. Natural emissions from vegetation and land amount to about 439 gigatons per year, and from oceans about 332 gigatons per year. If as Kerry says our HFC emissions have equivalent warming effect to 1 gigaton of CO2, that makes their effect about 1/29th (3.4%) of human CO2 emissions and 1/800th (0.125%) of combined human and natural emissions.

More important is the total radiative forcing that would come from those HFC emissions. As Cornwall Alliance Senior Fellow Dr. Roy W. Spencer pointed out over on Facebook, according to the IPCC, HFCs account for only about 1% of the total radiative forcing supposedly driving anthropogenic global warming. Even assuming the IPCC’s estimate (which probably exaggerates by two to three times) that doubling CO2-equivalent concentration in the atmosphere would cause about 1.5C to 4.5C of warming over the next century or two, that means HFCs would drive only about 0.015C to 0.045C of that warming—the health risks of which to humanity are essentially zero.

So is amending the Montreal Protocol to limit HFC use “of equal importance” with fighting ISIS, as Kerry said?