Huge permafrost thaw can be limited by ambitious climate targets

April 10, 2017, University of Leeds
Drone image -- thawing permafrost peat plateaus in northern Norway. Credit: Sebastian Westermann

Global warming will thaw about 20% more permafrost than previously thought, scientists have warned—potentially releasing significant amounts of greenhouse gases into the Earth's atmosphere.

A new international research study, including change experts from the University of Leeds, University of Exeter and the Met Office, reveals that permafrost is more sensitive to the effects of global warming than previously thought.

The study, published today in Nature Climate Change, suggests that nearly 4 million square kilometres of frozen soil—an area larger than India—could be lost for every additional degree of global warming experienced.

Permafrost is frozen soil that has been at a temperature of below 0ºC for at least two years. Large quantities of carbon are stored in organic matter trapped in the icy permafrost soils. When permafrost thaws the organic matter starts to decompose, releasing greenhouse gases such as carbon dioxide and methane which increase global temperatures.

It is estimated that there is more carbon contained in the frozen permafrost than is currently in the atmosphere.

Thawing permafrost has potentially damaging consequences, not just for greenhouse gas emissions, but also the stability of buildings located in high-latitude cities.

Roughly 35 million people live in the permafrost zone, with three cities built on continuous permafrost along with many smaller communities. A widespread thaw could cause the ground to become unstable, putting roads and buildings at risk of collapse.

Recent studies have shown that the Arctic is warming at around twice the rate as the rest of the world, with permafrost already starting to thaw across large areas.

The researchers, from Sweden and Norway as well as the UK, suggest that the huge permafrost losses could be averted if ambitious global climate targets are met.

Lead-author Dr Sarah Chadburn of the University of Leeds said: "A lower stabilisation target of 1.5ºC would save approximately two million square kilometres of permafrost.

Achieving the ambitious Paris Agreement climate targets could limit permafrost loss. For the first time we have calculated how much could be saved."

In the study, researchers used a novel combination of global climate models and observed data to deliver a robust estimate of the global loss of permafrost under .

The team looked at the way that permafrost changes across the landscape, and how this is related to the air temperature. They then considered possible increases in air temperature in the future, and converted these to a permafrost distribution map using their observation-based relationship. This allowed them to calculate the amount of permafrost that would be lost under proposed climate stabilisation targets.

As co-author Professor Peter Cox of the University of Exeter explained: "We found that the current pattern of permafrost reveals the sensitivity of permafrost to global warming."

The study suggests that permafrost is more susceptible to global warming that previously thought, as stabilising the climate at 2ºC above pre-industrial levels would lead to thawing of more than 40% of today's permafrost areas.

Co-author Dr Eleanor Burke, from the Met Office Hadley Centre, said: "The advantage of our approach is that permafrost loss can be estimated for any policy-relevant global warming scenario.

"The ability to more accurately assess loss can hopefully feed into a greater understanding of the impact of global and potentially inform policy."

Explore further: New permafrost map shows regions vulnerable to thaw, carbon release

More information: An observation-based constraint on permafrost loss as a function of global warming, Nature Climate Change (2017). nature.com/articles/doi:10.1038/nclimate3262

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14 comments

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aksdad
1.3 / 5 (12) Apr 10, 2017
Why would we want to limit widespread permafrost thaw? Is there any paleoclimate data to show that it would be detrimental? We know that at the peak of the previous interglacial warm period about 125,000 years ago sea levels were 4 to 6 meters higher than present so presumably it was also warmer and much of the current permafrost had warmed. Was there anything bad about that?

https://www.giss....nitz_09/

Certainly 4 to 6 meters of additional sea level rise is a big problem for coastal communities, but paleoclimate records show that nature has repeated this cycle of cooling and warming at least 8 times in the last million years and appears to be unavoidable.

https://www.clima...arge.png

The good news is the current rate of sea level rise is so slow it will take thousands of years to increase another 4 to 6 meters.

https://climate.n...a-level/
SteveS
4.5 / 5 (15) Apr 11, 2017
The good news is the current rate of sea level rise is so slow it will take thousands of years to increase another 4 to 6 meters.


You assume that the rate of change will remain linear, do you have any basis for that belief?
ekim
4.1 / 5 (10) Apr 11, 2017
,but paleoclimate records show that nature has repeated this cycle of cooling and warming at least 8 times in the last million years and appears to be unavoidable.

Why do you assume that we are in the part of the cycle that is naturally warming. We could very well be in a cooling phase, but changes in atmospheric composition has altered the outcome. When we do reach a natural warming phase, the effect could be compounded to produce even greater warming. The physical properties of CO2 are well known, however the causes of past global warming or cooling is not.
antigoracle
1.4 / 5 (11) Apr 11, 2017
LOL...NASA squandered millions looking for GHG release in Alaska and when they couldn't they just made some shit up and decided more millions should be wasted.
antialias_physorg
4.6 / 5 (11) Apr 11, 2017
You assume that the rate of change will remain linear, do you have any basis for that belief?

It's pretty much an indicator of someone who doesn't understand climate change (or science in general) when they always assume
- changes are always linear and can be extrapolated linearly forever
- temperature change by x degrees means that everywhere on the planet will have the same weather as today but only exactly x degrees warmer
- changes like sea level rise apply everywhere exactly the same

They failed basic high school education. There's really no point in trying to get them to understand an issue like climate change. You'd have to start them over with basic math concepts.

In the grand scheme of things these people just don't matter. Forget them.
EyeNStein
3.1 / 5 (7) Apr 11, 2017
Those climate targets will have to be combined with a worldwide commitment to leave profitable fossil fuels in the ground, which I don't see happening.
Otherwise falling demand for fossil fuels will make them even cheaper and someone somewhere will turn/burn them into dollars: So CO₂ will keep increasing faster as it has since 1970.

If the permafrost does keep melting and releasing methane the warming will accelerate and New York will be facing a 6m higher tide sooner than you think.
TheGhostofOtto1923
3 / 5 (3) Apr 11, 2017
How long before this land dries out enough so we can begin building housing tracts, strip malls, and amazon distribution centers?

Global warming has the great quality of making the most volatile and disruptive parts of the world uninhabitable. And in the meantime as violence increases due to dwindling resources and fevered brows, the most pragmatic, resourceful, and ambitious of the inhabitants will leave their obsolete cultures behind to find better lives.

Eyenstein should be interested to know that this rarifaction process is metaphorically described in his book. God repeatedly tempts his people in order to identify the weak and gullible, who are then culled, leaving the remnants (the chosen ones?) to carry on.

The Thirty Years War is a favorite example.

Without the lions and tigers to keep the herd healthy, this vital Task is left to the Shepherds.

It is written.
TheGhostofOtto1923
2.8 / 5 (4) Apr 11, 2017
New York will be facing a 6m higher tide sooner than you think
-Indeed another good example. The infrastructures of coastal cities around the world are old, obsolete, and beyond repair. Their sewer and storm systems for instance are combined and inseparable.

Fully half the potable water entering manhattan leaks away before it can be consumed. These cities have already begun to collapse and depopulate.

Global warming offers a unique form of urban renewal, akin in some respects to shermans march to the sea.

Rome was abandoned not so much because the empire had collapsed but it had become unlivable. Like the city mounds throughout the middle east, it had become unsupportable.

The Real Empire had anticipated this for generations and had begun preparing europe as the next seat of world power. They even created a new religion custom-tailored to consolidate all the warring tribes there and make the people more susceptable to central rule.
aksdad
1 / 5 (5) Apr 12, 2017
You assume that the rate of change will remain linear, do you have any basis for that belief?

I don't assume that the rate of sea level rise will remain linear, but based on tide gauge observations of the last 140 years the long term trend is essentially linear, which you can see in the 3rd link I provided. Until we see a change in trend, linear is the best assumption.

With every meter of sea level rise oceans have to fill in increasingly larger volumes of water because the surface area is much larger. It would take a pretty dramatic rate increase in glacier melt to increase the rate of sea level rise.

So using my lousy high school math skills, 4 meters is 4,000 millimeters and 1.5 mm per year into 4,000 is...lemme see, duh...40,000 divided by 15, carry the 10, append 0, divide again by 15...long division is so hard. I'll just use a calculator. 2,666 years. Or if you go with satellite measurements at 3.4 mm/yr, it's 1,176 years.
aksdad
1 / 5 (5) Apr 12, 2017
Why do you assume that we are in the part of the cycle that is naturally warming. We could very well be in a cooling phase, but changes in atmospheric composition has altered the outcome.

Excellent point! So which would you prefer? Heading back into the next Ice Age with mile-thick glaciers extending down into the northern United States and northern Europe, or something like what we have right now with maybe another degree or two of warming? I'd prefer the latter, but maybe you think glaciers are cozy and really excellent for agriculture....
SteveS
5 / 5 (4) Apr 12, 2017
I don't assume that the rate of sea level rise will remain linear, but based on tide gauge observations of the last 140 years the long term trend is essentially linear, which you can see in the 3rd link I provided. Until we see a change in trend, linear is the best assumption.


Looking at the source data for the graphs on the 3rd link you provided it's clear that the rate of increase has increased over time. You can check this for yourself, just paste the data into excel and compare the linear trend of the first half of the data to the second half of the data. The fact that this change is even evident in the much shorter 23 year satellite dataset shows that an increasing rate of change rather than linear is the best assumption based on the historical evidence.


Satellite Data
ftp://podaac.jpl....1701.txt

Tide Gauge Data
http://doi.org/10...59E3ACE4
antigoracle
1 / 5 (6) Apr 12, 2017
Otherwise falling demand for fossil fuels will make them even cheaper and someone somewhere will turn/burn them into dollars: So CO₂ will keep increasing faster as it has since 1970.

Seriously, you must change your handle to EyeStupid. How does your tripe make any logical sense?
EyeNStein
5 / 5 (1) Apr 14, 2017
Dirty black crude oil being fracked out of a pristine arctic environment is such a good metaphor for what we as a species really think about climate targets.
(And you know I cant resist a good metaphor.)

http://theconvers...om-75683
howhot3
5 / 5 (1) Apr 17, 2017
Why would we want to limit widespread permafrost thaw?
Yeah! Yeah! {think fascist crowd with torches and pitchforks} Crowd shouts "Bring on the extinction!" "It ain't so tough!". "Burn more coal!", "Destroy it", "Choke on my black diesel smoke!".

You bunch of brainwashed dumb ass rightwing fascist loving climate denier goons. Get a bain mowan.

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