Climate scientists demystify the point of no return article

Thursday a new study came out warning that even if we stop emitting carbon dioxide, the world has reached the ‘point of no return’ of climate change. The paper claims this is because arctic permafrost – a carbon-rich, permanently frozen land made up of rocks, water and dead wildlife – is irreversibly melting and could continue to heat the planet for decades to come. centuries by releasing carbon dioxide. Terrifying, right?

The only solution, the authors say, is to suck carbon from the air along with carbon capture, which is not yet proven to work on a large scale, or even to use more dangerous geoengineering technologies. The results and conclusions of the study were widely covered and a little out of breath, but here’s the thing: Analysis has big problems.

“To be frank, the document is crap that shouldn’t have passed a competent peer review,” said Zeke Hausfather, climatologist and energy systems analyst. “It’s an interesting thought-provoking experiment, but its results should be taken with extreme skepticism until more complex models of the Earth system produce similar results.”

The study’s problems begin with its title, which refers to “melting permafrost”. It’s a red flag because, as noted by Merritt Turetsky, an environmentalist who heads the Institute for Arctic and Alpine Research at the University of Colorado at Boulder, permafrost thaws rather than melts.

“Ice packs stored here and there in permafrost can melt,” she says. “But these are very distinct processes.” This distinction, she says, makes her think researchers don’t really know what permafrost is.

Before I even got into the body of the study, the credited authors made me raise my eyebrows. They are not climatologists, they are business school professors. And it shows in the report, because their model is simplistic. Climate scientists have spent decades developing models that take into account the subtleties of climate. More complex models, for example, better illustrate ocean circulation patterns, which can have a significant effect on long-term warming. They also more accurately display the amount of water vapor in the atmosphere, which is a natural source of short-lived but common warming. The new paper model lacks a lot.

“It doesn’t explicitly include things like large-scale movements of air and water in the atmosphere and the ocean,” said Kate Marvel, a climatologist at the Goddard Institute for Space Studies. The NASA.

The new report also overestimates water vapor concentrations, causing the model to heat up unusually. Another major flaw in the model also overestimates the warming potential of methane emissions. The authors claim that methane will be the primary driver of future temperature increases, but in doing so, they exaggerate the temperature increase that methane concentrations in their model could produce.

More advanced models, Marvel said, are “more tied to reality” in their illustrations of water vapor concentrations and the timeline over which arctic ice melts and permafrost melts. This allows them to provide a more accurate picture of how and when these changes could create feedback loops where melting and thawing release more greenhouse gases and thus heat the planet. Because of these inaccuracies, the oversimplified model distorts the amount of warming we would really see if we reduced our emissions immediately.

“Modern and complex models of the Earth system generally show minimal warming initiated in the future after zero emissions, even taking into account our best estimate of future permafrost melt,” said Hausfather.

Specifically, the new report contrasts sharply with the most recent findings of the United Nations. Intergovernmental Panel on Climate Change and the European Geosciences Union.

“People miss that this is a simple model created by non-experts,” he said. “I’m also concerned that there is a bit of bias to cover it up given its alleged dramatic findings.”

He noted that a 2019 meta-analysis of 18 models of the Earth system actually found that the immediate cessation of greenhouse gas emissions would have drastically limit warming, but received much less coverage than the new paper.

To be clear, no climate scientist is claiming that warming feedback loops are not a problem or that melting permafrost releases methane. And that certainly doesn’t mean we shouldn’t act to reduce emissions quickly. But Marvel said that by focusing on greenhouse gases from thawing arctic soil, the authors’ suggestions for the future are all wrong.

“I want to be clear: melting permafrost is likely to lead to a net increase in methane concentrations in the atmosphere. And methane is a powerful greenhouse gas. But the methane concentrations are increasing sharply right now, and it’s not because of the permafrost, ”she says. “It’s because of the oil and gas industry and large-scale agriculture.”

It may be predictable to say, but it turns out that we need to cut our carbon emissions and phase out oil and gas immediately. The necessary changes will not be easy to implement. Like a IPCC groundbreaking report 2018 said, they will demand “unprecedented changes in all aspects of society.” But the alternative is much worse, even without the fear of permafrost methane.

“If we can get our emissions down to zero, lower atmospheric CO2 concentrations will more than offset additional future emissions from melting permafrost,” Hausfather said.