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kassy

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Permafrost general science thread
« on: January 16, 2019, 02:42:56 PM »
I decided to make a new thread for general science on permafrost because the other threads are about either methane or snow cover or really specific issues.


*

The pace at which the world's permafrost soils are warming

As the new global comparative study conducted by the international permafrost network GTN-P shows, in all regions with permafrost soils the temperature of the frozen ground at a depth of more than 10 metres rose by an average of 0.3 degrees Celsius between 2007 and 2016 - in the Arctic and Antarctic, as well as the high mountain ranges of Europe and Central Asia. The effect was most pronounced in Siberia, where the temperature of the frozen soil rose by nearly 1 degree Celsius. The pioneering study has just been released in the online journal Nature Communications.

...

The complete dataset encompasses 154 boreholes, 123 of which allow conclusions to be drawn for an entire decade, while the remainder can be used to refine calculations on annual deviation. The results show that, in the ten years from 2007 to 2016, the temperature of the permafrost soil rose at 71 of the 123 measuring sites; in five of the boreholes, the permafrost was already thawing. In contrast, the soil temperature sank at 12 boreholes, e.g. at individual sites in eastern Canada, southern Eurasia and on the Antarctic Peninsula; at 40 boreholes, the temperature remained virtually unchanged.

...

The researchers observed the most dramatic warming in the Arctic: "There, in regions with more than 90 percent permafrost content, the soil temperature rose by an average of 0.30 degrees Celsius within ten years," reports first author Dr Boris Biskaborn, a member of the research group Polar Terrestrial Environmental Systems at the Potsdam facilities of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research. In northeast and northwest Siberia, the temperature increase at some boreholes was 0.90 degrees Celsius or even higher. For the sake of comparison: the air temperature in the respective regions rose by an average of 0.61 degrees Celsius in the same period.

Farther south, in Arctic regions with less than 90 percent permafrost, the frozen ground only warmed by 0.2 degrees Celsius on average. "In these regions there is more and more snowfall, which insulates the permafrost in two ways, following the igloo principle: in winter the snow protects the soil from extreme cold, which on average produces a warming effect. In spring it reflects the sunlight, and prevents the soil from being exposed to too much warmth, at least until the snow has completely melted away," Biskaborn explains.

Significant warming can also be seen in the permafrost regions of the high mountain ranges, and in the Antarctic. The temperature of the permanently frozen soils in the Alps, in the Himalayas and in the mountain ranges of the Nordic countries rose by an average of 0.19 degrees Celsius. In the shallow boreholes in the Antarctic, the researchers measured a rise of 0.37 degrees.

for full details:
https://www.eurekalert.org/pub_releases/2019-01/awih-tpa011519.php

Bernard

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Re: Permafrost general science thread
« Reply #1 on: January 16, 2019, 11:35:54 PM »
I just read the quoted article at phys.org
https://phys.org/news/2019-01-pace-world-permafrost-soils.html
One thing I was wondering is if similar studies are conducted in other places than permafrost. We have measures of sea water temperatures at different depths, but the global warming should also be measured in mean temperatures of underground, at depths where the temperature is stable year-round (about 10-20m if what I read is correct), whether this underground is frozen or not.
This is a bit off-topic, please point me to an existing thread if any.

Meanwhile, I created one such topic
https://forum.arctic-sea-ice.net/index.php/topic,2548.0.html
« Last Edit: January 17, 2019, 12:21:38 AM by Bernard »

wdmn

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Re: Permafrost general science thread
« Reply #2 on: April 16, 2019, 02:09:13 AM »
Warming Arctic permafrost releasing large amounts of potent greenhouse gas

Quote
A recent study shows that nitrous oxide emissions from thawing Alaskan permafrost are about twelve times higher than previously assumed. About one fourth of the Northern Hemisphere is covered in permafrost, which is thawing at an increasing rate. As temperatures increase, the peat releases more and more greenhouse gases. And, even though researchers are monitoring carbon dioxide and methane, no one seems to be watching the most potent greenhouse gas: nitrous oxide.

https://www.sciencedaily.com/releases/2019/04/190415090848.htm

DaveHitz

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Re: Permafrost general science thread
« Reply #3 on: April 16, 2019, 02:43:27 AM »
Quote
A recent study shows that nitrous oxide emissions from thawing Alaskan permafrost are about twelve times higher than previously assumed.

This is clearly no laughing matter...

gerontocrat

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Re: Permafrost general science thread
« Reply #4 on: April 23, 2019, 03:06:30 PM »
A new study says the release of methane and carbon dioxide from thawing permafrost will accelerate global warming and add up to $70tn (£54tn) to the climate bill. Tried to find the article and failed. See summary from the guardian way down below or go to ...https://www.theguardian.com/environment/2019/apr/23/melting-permafrost-in-arctic-will-have-70tn-climate-impact-study

But I did find instead
https://www.nature.com/articles/s41467-018-08.240-4 that shows worrying increases in the temperature of permafrost all over the Arctic

Permafrost is warming at a global scale
Quote
Abstract
Permafrost warming has the potential to amplify global climate change, because when frozen sediments thaw it unlocks soil organic carbon. Yet to date, no globally consistent assessment of permafrost temperature change has been compiled. Here we use a global data set of permafrost temperature time series from the Global Terrestrial Network for Permafrost to evaluate temperature change across permafrost regions for the period since the International Polar Year (2007–2009). During the reference decade between 2007 and 2016, ground temperature near the depth of zero annual amplitude in the continuous permafrost zone increased by 0.39 ± 0.15 °C. .....
Introduction
Carbon release resulting from permafrost degradation will potentially impact the Earth’s climate system because large amounts of carbon previously locked in frozen organic matter will decompose into carbon dioxide and methane. This process is expected to augment global warming by 0.13–0.27 °C by 2100 and by up to 0.42 °C by 2300. Despite this, permafrost change is not yet adequately represented in most of the Earth System Models14 that are used for the IPCC projections for decision makers. One major reason for this was the absence of a standardized global data set of permafrost temperature observations for model validation.
________________________________________________

Melting permafrost in Arctic will have $70tn climate impact - study
Study shows how destabilised natural systems will worsen man-made problem

Quote
Jonathan Watts Global environment editor

The release of methane and carbon dioxide from thawing permafrost will accelerate global warming and add up to $70tn (£54tn) to the world’s climate bill, according to the most advanced study yet of the economic consequences of a melting Arctic.

If nations fail to improve on their current Paris agreement commitments, this feedback mechanism combined with a loss of heat-deflecting white ice will cause a near 5% amplification of global warming and its associated costs, says the paper, which was published on Tuesday in Nature Communications.

The authors say their study is the first to calculate the economic impact of permafrost melt and reduced albedo – a measure of how much light that hits a surface is reflected without being absorbed – based on the most advanced computer models of what is likely to happen in the Arctic as temperatures rise. It shows how destabilised natural systems will worsen the problem caused by man-made emissions, making it more difficult and expensive to solve.

They assessed stocks of CO2 and methane trapped in the permafrost by using samples taken from a depth of three metres at multiple points across the Arctic. These were run through the world’s most advanced climate simulation software in the US and at the UK Met Office to predict how much gas will be released at different levels of warming. Even with supercomputers, the number crunching took weeks because the vast geography and complex climate interactions of the Arctic throw up multiple variables. The researchers then applied previous economic impact models to assess the likely costs.

Permafrost melt is the main concern. Greenhouse gases, which have been frozen below the soil for centuries, have already begun to escape at the current level of 1 degrees Celsius of global heating. So far the impact is small. Ten gigatonnes of CO2 have been released from the ice but this source of emissions will grow rapidly once temperatures rise beyond 1.5C.

On the current trajectory of at least 3C of warming by the end of the century, melting permafrost is expected to discharge 280 gigatonnes of carbon dioxide and 3 gigatonnes of methane, which has a climate effect that is 10 to 20 times stronger than CO2.

This would increase the global cost of destruction, adaptation and emissions reduction by $70tn between now and 2300. This is 10 times higher than the projected benefits from a melting Arctic, such as easier navigation for ships and access to minerals, says the paper.
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gerontocrat

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