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Refrigerants versus CO2 versus settled science

12 Apr 2023 | Science Notes

From the Settled Science Department comes news that chemicals long known to affect the ozone layer also have caused more warming, especially in the Arctic, than previously thought. A new study by scientists in Canada, the US, the UK and Austria took a look at how much warming these gases caused during the half century from 1955 to 2005. And they found, admittedly based on model simulations so caveat emptor, that they were likely responsible for about 30% of global warming generally, and about 37% of Arctic warming in particular. Which is interesting because it is 2023 and back in 2005 we were already being told that the science was settled and the dominant role of CO2 in causing climate change had been proven beyond dispute. But it turns out, to no one’s surprise, that things were not as simple as we were told. And they still aren’t.

One way the authors highlight the importance of the results is to point out that over the 50 year period from 1955 to 2005, ozone-depleting chemicals were responsible for 61% of the warming attributable to carbon dioxide. The idea that CO2 is a bogeyman responsible for all the warming of recent decades is clearly untrue.

This finding raises a scientific point that studies blaming CO2 for climate change have tended to work on the idea that, if they can’t blame it on the sun or volcanoes, then it must be CO2 because what else would cause warming? Now we have a viable alternative, or at last now climate modelers have something to look at. And if there’s one, why not more than one.

The finding therefore raises an important policy point. It’s proving very difficult to reduce CO2 emissions because they are closely tied to fossil fuel use and people just won’t be sensible and let the government cut their access to inexpensive fuel for heating, cooking, lighting and transportation and hope they’re OK being stuck cold and hungry in the dark where they are. But emissions of ozone-depleting substances have been reduced substantially since the Montreal Protocol was signed in1987 because it turned out there were effective and inexpensive substitutes to refrigerants, unlike fuels, so we could phase the former out relatively easily. And if we can curtail nearly as much warming as we expect from CO2 by continuing the phaseout of ozone-depleting gases, which we were going to do anyway, then there’s not as much pressure to inflict misery on the world by trying to get rid of fossil fuels.

Somebody somewhere ought to look into that.

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