The tundra and snow capped mountains off in the distance in Nome Alaska.

Study finds sinking tundra surface unlikely to trigger runaway permafrost thaw

Peer-Reviewed Publication

DOE/OAK RIDGE NATIONAL LABORATORY

Arctic polygonal tundra
IMAGE: ORNL SCIENTISTS CREATED A HIGH-PERFORMANCE SIMULATION OF THE ARCTIC TUNDRA THAT FOUND THE PROCESS OF SOIL SUBSIDENCE DUE TO PERMAFROST THAW WOULD BE SELF-LIMITED IN THE DECADES AHEAD. view more CREDIT: DAVID GRAHAM, ORNL/U.S. DEPT. OF ENERGY

Oak Ridge National Laboratory scientists set out to address one of the biggest uncertainties about how carbon-rich permafrost will respond to gradual sinking of the land surface as temperatures rise. Using a high-performance computer simulation, the research team found that soil subsidence is unlikely to cause rampant thawing in the future.

This permanently frozen landscape in the Arctic tundra, which has kept vast amounts of carbon locked away for thousands of years, is at risk of thawing and releasing greenhouse gases into the atmosphere.

The United Nation’s Intergovernmental Panel on Climate Change has identified the possibility of soil subsidence leading to a feedback loop that could trigger a rapid thaw as a major concern in the decades ahead. Accelerated thawing caused by uneven land subsidence has been observed on smaller scales over shorter time frames, but the IPCC’s assessments were uncertain as to what may happen over the long term.

That’s where ORNL stepped in with its Advanced Terrestrial Simulator, or ATS, a highly accurate, physics-based model of the region’s hydrology fed by detailed, real-world measurements to help scientists understand the land’s evolution.

What they found is that even though the ground will continue to sink as big ice deposits melt, the uneven subsidence also leads to a drier landscape and limits the process’s acceleration through the end of the century, as described in the Proceedings of the National Academy of Sciences.

“Improved drainage results in a drier landscape over a decadal timescale, and the process then becomes self-limiting,” said Scott Painter, who leads the Watershed Systems Modeling group at ORNL.

The scientists focused on a large region of the tundra characterized by ice wedges — long pieces of ice that crack the surface and extend belowground to create polygonal forms in the Arctic landscape. The cryo-hydrology simulations were informed by measurements gathered in the polygonal tundra.

The ATS was first developed for the Department of Energy’s NGEE Arctic project led by ORNL, focused on observations, experiments and modeling of the environmental processes at play in the region to improve climate predictions.

“We looked at the microtopography caused by these ice wedges in the subsurface and how that controls the flow of water,” Painter said. “Ours is the first capability to capture the effect of changing microtopography and represent it in climate models.”

Painter added that the team has a high degree of confidence in the model since it was developed for NGEE Arctic and has been evaluated against the project’s real-world observations.

He noted that most models, including ORNL’s, are in agreement in generally projecting large amounts of carbon thaw in the Arctic as temperatures rise. “But here, we have identified that one of the most worrisome processes, this runaway thawing due to subsidence, is unlikely to occur over a long time frame.”

The study pointed out other implications of a drying landscape. “As the polygonal tundra gets very dry, by the year 2100 it could have ecological impacts for migratory birds, which use these ecosystems as breeding grounds,” Painter said.

Other scientists collaborating on the study include ORNL’s Ethan Coon; Ahmad Jan, formerly of ORNL and now at the NOAA-affiliated Office of Water Prediction; and Julie Jastrow of Argonne National Laboratory.

The research was supported by NGEE Arctic, which is sponsored by the DOE Office of Science’s Biological and Environmental Research Program and led by ORNL, and BER’s Environmental System Science Program at Argonne. NGEE Arctic supported the original development of ATS as well as recent enhancements to incorporate subsidence into the model.

UT-Battelle manages ORNL for DOE’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. DOE’s Office of Science is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science


JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2212171120 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Drying of tundra landscapes will limit subsidence-induced acceleration of permafrost thaw

ARTICLE PUBLICATION DATE

13-Feb-2023

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strativarius
February 22, 2023 2:23 am

Good start: “carbon rich…” and making it into the first paragraph… “Using a high-performance computer simulation”

Oh dear. That’s it; game over. And just to make sure it sounds like nonsense add in phrases like: “large amounts of carbon thaw”.

I recommend a course of cryotherapy (geddit?!)

joe x
February 22, 2023 3:41 am

second paragraph,
“This permanently frozen landscape in the Arctic tundra, which has kept vast amounts of carbon locked away for thousands of years, is at risk of thawing and releasing greenhouse gases into the atmosphere.”

is this an admission that co2 follows temperature?

strativarius
Reply to  joe x
February 22, 2023 3:59 am

I think they would claim it as one of their runaway positive feedback loops. What else can they do?

DonM
Reply to  strativarius
February 22, 2023 10:37 am

who put all that rich carbon under/in the frozen soils … how did it get there?

AndyHce
Reply to  joe x
February 22, 2023 1:32 pm

It seems to be an admission of neoglacialism, that frozen tundra is, at least in part, a product of the past several thousand years’ overall cooling rather than a long term feature.

Ron Long
February 22, 2023 3:55 am

Oakridge? As a geologist that fought against permafrost, at the Egnaty Creek mercury prospect, below Red Devil along the lower Kuskokwim River in Alaska, as far as I am concerned they can nuke that stuff.

Peta of Newark
February 22, 2023 4:13 am

How is it possible to get something so simple, so wrong/
Flippant: Easy, use a computer

The Carbon remains in the ground (whether its frozen or not) because or when the ground is permanently waterlogged.
Meanwhile, I am sooo struggling as to how warming causes subsidence – what is the mechanism?

Anyway, they assert that The Ground is going to dry out,
Unfortunately that is going to cause the ‘stored carbon’ to simply explode.
Because then, Oxygen will get into the ground and mix with the stored carbon.
The Oxygen will then do what Oxygen always does best = Oxidise things

It is The Exact Process of chemical soil erosion (as opposed to physical erosion where the soil washes or blows away) – where soil bacteria and fungi go on an Oxygen fuelled eating spree and consume everything. Even themselves ultimately
And all that’s left is a humongous cloud of CO2 left floating in the sky
Even worse, while the stored carbon and bacteria were all still there, they retained immense amounts of water – so when The Sun Shone, it had much less heating effect than when if the soil was/is bone dry.
With the water gone, It Will Get Hot There.

Moral of this story: Really really scary but what is The Prime Reason why John Deere’s invention was soooo successful?
Because it dried out the soil, lowered its Albedo (raised temperature) and let Oxygen permeate to depths it couldn’t previously
Things then goes off ‘Scale Bad’ when along comes Peta da Peasant and heaps Ammonium Nitrate (AN) into the chewed up bone-dry morass that was once a prairie field.
Read on *every* sack of AN: Caution: Oxidising Agent
(That’s not the mechanism but the effect is the same)

And turns said chewed up morass into a burnt out chewed up morass while Sol beams down and makes it even an hotter, ever drier and ever more burnt out morass.

That was being kind: Read= Actual bombsite of pure, absolute and total destruction perfectly devoid of water & life.

Ah well, as long as another John Deere device (the combine harvester) rescues a few sacksfull of sugar from this disaster-zone, we can all sit back and conclude:
Everything has never been better

Life may be sweet but sugar is not
If only the muppets here could figure that out but, what will it take to do that

Tom Abbott
February 22, 2023 5:41 am

From the article: “What they found is that even though the ground will continue to sink as big ice deposits melt,”

Assuming melting [warming] continues into the future. Climate Science is made up of speculation, assumptions, and assertions. This is another one of them.

Meanwhile, the global temperatures have cooled by 0.7C since the 2016 highpoint.

comment image

RickWill
Reply to  Tom Abbott
February 22, 2023 2:08 pm

Meanwhile, the global temperatures have cooled by 0.7C since the 2016 highpoint.

The problem with the notion of “global temperature” is that it fails on two key aspects to convey any meaning. There is no “global” warming or “global” cooling. Some parts are warmer and some parts are cooler. Note the scale on the chart is “departure” it is not temperature. In fact UAH average is around 273K but the “departure” is shown in the chart.

You get a different perspective if the “departure” is viewed spatially:
comment image

The place where permafrost exists is on fire if you accept the NASA “departure” color coding on the image. However that fire is mostly occurring in winter. January temperature in the Arctic has shown a warming trend for at least the past 60 years and it will continue for a lot longer yet. But the actual temperature is still a long way below zero on land.

Humans will observe the permafrost moving southward again long before the NH land masses are observed to cool.

Last edited 26 days ago by RickWill
Tom Abbott
Reply to  RickWill
February 22, 2023 2:54 pm

“But the actual temperature is still a long way below zero on land.”

A key point.

I agree with you that parts of the globe are cooling while other parts are warming.

I just wanted to throw a little cold water on the alarmist focus on warming. Their expectations cause them to disregard reality. So I’m helping them out.

Alpha
February 22, 2023 6:40 am

9000 years ago in Sweden, mountain birch and Scots pine grew 600 – 700 m higher than they do today.

It’s much colder now than it was back then.

Lee Riffee
Reply to  Alpha
February 22, 2023 8:10 am

Yes. If scientists want to see what things might be like if it gets a little bit warmer, why not look back in time to when the earth was warmer than it is now? IMO there is no need for any computer models because we already know what happened when the earth was warmer, even much warmer, than now. Polar bears didn’t go extinct, the oceans did turn acidic and boil, and of course there was no horrible catastrophe that some falsely fear today. And our own species did quite well in those warm times….

AndyHce
Reply to  Alpha
February 22, 2023 1:43 pm

At that latidude, due, at least in large part, to precession exposing the far north to much more summer sunlight, many times greater than anything attributed to greenhouse gases.

DMacKenzie
February 22, 2023 7:40 am

The permafrost line has moved from a bit south of the US-Canada border to the Arctic circle over the last 8000 years. Negative effects, NONE KNOWN, and millions of tons of CO2 have been sequestered in the boreal forests.

Dave Burton
Reply to  DMacKenzie
February 22, 2023 11:57 am

Well, I’d say that millions of tons of CO2 sequestered” is a negative effect. The best scientific evidence is that increased atmospheric CO2 is beneficial, and decreased atmospheric CO2 is detrimental.

But I agree that there’ve been no other negative effects.

https://sealevel.info/negative_social_cost_of_carbon.html

Sunsettommy
Editor
Reply to  DMacKenzie
February 22, 2023 1:34 pm

It was down to around 42 degrees North in Europe and around the same in America.

Polar Bears are still here and so are Eskimos and other tribes in the far north as well as Caribou/Reindeer and Moose.

The Permafrost bugaboo is a dead-on arrival scaremongering baloney.

iflyjetzzz
February 22, 2023 8:33 am

Ah, I remember all of this. There was a panic running around the warmunist community about a decade ago. It went: ‘if the permafrost thaws, it will release greenhouse gases (emphasis on methane IIRC) which will create a runaway chain reaction that will rapidly increase the earth’s temperature.’ I was skeptical then; glad to see some warmunists walking it back now.

The good news about permafrost thawing is that it may increase the world’s arable land. More arable land is a good thing.

Dave Fair
Reply to  iflyjetzzz
February 22, 2023 10:46 am

The Warmunists ae not walking back anything. Note this only applies to deformation/drying of the landscape (a minor issue), not the whole runaway warming trope.

Dave Burton
February 22, 2023 10:21 am

My first thought was:

1. Isn’t “thawing due to subsidence” backward? I can see how thawing causes localized subsidence, but how does subsidence cause thawing?

But, no, that really is what they mean. The paper says, “Permafrost thaw as measured by the increase in active layer thickness (ALT)—the thickness of the soil layer that thaws each summer—is accelerated by subsidence, but the effect is relatively small.”
 

My second thought was:

2. Anytime someone uses the word “runaway” in a sentence about climate feedbacks, without pooh-poohing it, it means they don’t know what they’re talking about. Fortunately, in this case they did pooh-pooh it.

Thankfully, they didn’t fret about methane, either.

The usual confusion about “runaway” feedbacks w/r/t permafrost concerns Permafrost/Methane Feedback. That theoretical feedback loop works like this: If the climate warms, it could melt some of the Arctic permafrost, and/or underwater methane clathrate (hydrate) deposits, causing the release of methane (and some CO2) into the atmosphere. Methane (CH4) is a greenhouse gas, so this should increase warming, making it a much-hyped positive feedback mechanism. However, according to recent research, this effect is currently small, and is likely to remain so.

That should be intuitively obvious when you realize that methane causes only a small fraction of 1° of warming, and small fraction of 1° of warming obviously can’t melt much permafrost. 0.1°C of warming would only shift isotherms about six miles. As usual, WUWT has a good article.

The dominant feedback mechanism involving methane is negative: Methane Oxidation Feedback. It is simply the fact that higher atmospheric methane levels sharply accelerate the rate of natural oxidative processes which remove it.

From 2012 to 2022 the atmospheric CH4 concentration increased from 1.8081 ppmv to 1.9135 ppmv, which is an average of +0.01054 ppmv per year. That’s (2.8442 Gt/ppmv × 0.01054 ppmv) = 0.0300 Gt. That’s at most 1/15 of the rate of natural CH4 removals, and less than 1/10 the estimated rate of anthropogenic CH4 emissions. (That’s in stark contrast to CO2, for which the atmospheric concentration growth rate is similar to the natural removal rate, and about 1/2 the rate of anthropogenic emissions!)

The fact that CH4 removal processes dwarf the rate of CH4 increase in the atmosphere means that atmospheric CH4 level responds very quickly to changes in CH4 emission rate, and if CH4 emission rates cease increasing then the level of CH4 in the atmosphere will rise only a few percent (roughly 0.1 ppmv) before plateauing.

Last edited 26 days ago by Dave Burton
Bob
February 22, 2023 3:26 pm

I don’t know whether to see this as good news or bad. I’m going for good I guess because they showed the UN wrong. The US needs to get out of the UN and the UN needs to get out of the US. More importantly the US needs to stop financing the UN.

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