Checking in With the Latest Climate Change Estimates

The poor climate campaign has been having a hard time getting its usual media attention amidst the more immediate panic and media freakout over COVID-19 (which is why CNN enlisted Greta Thunberg for a panel on COVID-19), and the economic cost of the virus shutdown is not helping the greens as a demonstration project of what would occur with their preferred policies that would shrink the world economy in the same way for decades.

As such there hasn’t been a lot of media attention about a new study that purports to narrow the range of possible climate outcomes later this century if we double the amount of carbon dioxide in the atmosphere. For more than 40 years now, successive UN IPCC climate reports has estimated the range to be between 1.5 degrees C to 4.5 degrees C. (Actually this is about the range first predicted as far back as the 1890s when climate science can be said to have been first invented, which means we haven’t really advanced our grasp of the matter in a century.)

Never mind the climate models and other problems that come to mind. Even if this range is correct, it doesn’t help us decide good policy very much. A 1.5 or even 2 degree C warming would be no big deal, and might even have more positive benefits than costs and harms. (The IPCC reports essentially admit this, though they do their best to avoid saying this directly—you have to read it very carefully.) But a warming of 4.5 degrees C would have significant negative effects and be very costly—though even at this high end it is not clear that constraining energy use now is the best policy for our successors 80 years from now, but this is a subject for another day.

The problem all along has been that the climate science community has not been able to narrow this range or estimate the probability for any particular point in between. This is known as the issue of “climate sensitivity.” In the new study a group of 25 climate scientists believe they have at last confidently narrowed the range to 2.6 to 3.9 degrees C. A one of the authors concludes in an article describing the study in The Hill, “our findings rule out scenarios where warming ends up being minor, but it also makes some truly catastrophic outcomes less likely.”

In other words, even if the climate models are correct, the worst case scenarios make climate change a normal human problem to be managed fitfully as we manage other serious problems, in fact perhaps a less serious threat than war, nuclear proliferation, or a more serious pandemic. But you’re not allowed to say this. Climate panic demands that you call it the Worst Crisis Ever To Face Mankind, an existential threat requiring vast more government control of people and resources. Funny how these problems always seem to have the same solution, whether it’s because we’re running out of energy, or because we aren’t running out of energy.

Chaser: Amusing passage from a brand new book on fungi by Merlin Sheldrake entitled Entangled Life: How Fungi Make Our Worlds, Change Our Minds & Shape Our Futures:

Fungi are prodigious decomposers, but of their many biochemical achievements, one of the most impressive is this ability of white rot fungi to break down the lignin in wood.  Based on their ability to release free radicals, the peroxidases produced b white rot fungi perform what is technically known as “radical chemistry.”  “Radical” has it right.  These enzymes have forever changed the way that carbon journeys through its earthly cycles.  Today, fungal decomposition — much of it of woody plant matter — is one of the largest sources of carbon emissions, emitting about eighty-five gigatons of carbon to the atmosphere every year.  In 2018, the combustion of fossil fuels by humans emitted around ten gigatons.

So maybe we can reduce carbon in the atmosphere by “crop-dusting” forests with massive amounts of Lotrimin?

(For the humorless among our readers, this is meant as a joke. Also, hat tip: Tyler Cowen at Marginal Revolution.)

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