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Effects & Impacts: Melting permafrost & burning ice

Image: Katie Orlinksy, National Geographic

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Melting permafrost and burning ice

Summary

“Methane’s increase since 2007 was not expected in future greenhouse gas scenarios compliant with the targets of the Paris Agreement, and if the increase continues at the same rates it may become very difficult to meet the Paris goals.” Nisbet et al 2019

Home > Climate wiki > Effects > Melting permafrost

Summary

“Methane’s increase since 2007 was not expected in future greenhouse gas scenarios compliant with the targets of the Paris Agreement, and if the increase continues at the same rates it may become very difficult to meet the Paris goals.” Nisbet et al 2019

2022 Updates from State of the Cryosphere Report: Permafrost

  • Nearly three dozen of the world’s leading permafrost researchers and policy experts published a consensus paper which identified several key messages:

1) It is not too late to prevent future permafrost loss by reducing fossil fuel emissions, but continued high emissions will accelerate permafrost thaw and related CO2 and methane emissions;

2) Urgent action is required to reduce intergenerational consequences;

3) Permafrost carries deep ecological and cultural significance for Arctic communities; and

4) There are no “miracle cures” to protect the global climate system from generations of unstoppable permafrost emissions without urgent and deep emissions cuts consistent with the 1 .5°C goal of the Paris Agreement.

  • The first observational evidence for increasing methane emissions from thawing permafrost was documented for the early summer months at a site in the Lena River delta, where emissions have been measured since 2004, likely due to earlier arrival (by 11 days) of warmer temperatures during this same period.
  • More incidents of extreme summer rainfall may increase the depth of permafrost thaw by more than 30% in the northeastern Siberian tundra. Under a high emissions scenario, precipitation in the Arctic is projected to increase by 60% by 2100 and increasingly shift from snow to rain due to rising air temperatures.
  • Rising summer temperatures have recently triggered widespread permafrost thaw across high-latitude regions of Alaska, with some permafrost now in a thawed state throughout the year. As temperatures increase, the thickness of these permanently thawed regions will progressively increase. Under a high-emissions scenario, three-quarters of Alaska’s discontinuous permafrost zone may reach this unfrozen state within the next decade, with the thawed depth increasing to 10 m or more by 2100.
  • Rising global temperatures have even accelerated permafrost thaw in Greenland, increasing the vulnerability of coastal mountain regions to unpredictable landslides and collapse. As temperatures reach new record highs, the increasing frequency and scale of landslides across Greenland pose an increasing risk to local communities.
  • If global mean temperature rises above 2°C, more than 75% of permafrost peatland regions in northern European and western Siberia will become too warm and wet to maintain permafrost by the 2060s. Strong action to reduce emissions and keep global temperatures well below 2°C may allow suitably cold and dry conditions in western Siberia to preserve at least parts of these regions. Even with low emissions however, models do not project a return to conditions suitable to maintain peatland permafrost in Norway, Sweden, Finland, and parts of Russia – suggesting that these permafrost peatlands are close or have already passed a tipping point.
  • Permafrost degradation underneath lakes and in their surroundings in Alaska can destabilize the ground, triggering rapid drainage and emptying the lake within several days to weeks due to thawing, erosion, or overflow. In northwestern Alaska, lake drainage rates are now ten times higher than their historical average in the 1980s, with 100–250 lakes rapidly lost each year.
  • The presence of infrastructure built on permafrost ground usually increases the amount of heat entering the soil compared to undisturbed tundra, accelerating thaw and increasing the risk of collapse. According to AMAP’s latest Climate Update, more than 66% of Arctic settlements are located on permafrost and, in Alaska, permafrost thaw will increase cumulative maintenance costs of public infrastructure by an estimated US $5.5 billion by 2100 . Reducing emissions will help curb temperature rise and limit damage.
  • Increasing wildfires in the Arctic due to warmer and drier conditions also cause deeper and more rapid post-fire permafrost thawing.2At high latitudes, where much of the permafrost domain is located, most emissions from wildfire originate from below-ground combustion – rather than the combustion of above-ground biomass. Like emissions from other abrupt thaw events, these fire-related emissions from direct combustion, or from the effects of fire are typically excluded from global-scale models.
  • Calculations of the remaining planetary carbon budget must take these indirect human-caused emissions from permafrost thaw into account to accurately determine when and how emissions reach “carbon neutrality”; and not just through 2100, but well into the future. This is because the thawing of permafrost is a slow process and because once thawed, permafrost soils continue to emit carbon for at least 100 years, and possibly several centuries.

Melting permafrost (Northern Hemisphere only)

Fig. 1: Estimated permafrost changes between 2003 and 2017. Images: International Cryosphere Climate Initiative presentation at the COP26 Cryosphere Pavillion.

Video 1: Methane bubbles forming beneath lakes.

Unlike ice, permafrost doesn’t ‘melt’ once temperatures rise above 0°C. It falls apart and the organic material decomposes, just as frozen meat or vegetables left outside a freezer will decompose if not eaten. If permafrost decomposes in an environment where there’s oxygen, then carbon dioxide is released. If the environment is anaerobic (lacks oxygen), methane, which is 23 times more potent that carbon dioxide as a greehouse gas, is released. This enters the atmosphere either directly or via lakes and ponds (Videos 1 & 2).

“We managed to put a finger on when exactly when continuous permafrost melt starts…this is probably the tipping point, 1.5°C  warming.” – Dr Anton Vaks, Oxford University (Video 2).

Video 2: Methane ‘bursts’; at the time of this video in 2013, the average rise in global temperatures was 0.8°C. In 2020 it was an average 1.1°C and climbing. In June 2020, parts of the Russian Arctic reached 45°C (Fig. 1).

“…ice sheets overlie extensive, biologically active methan-ogenic wetlands and high rates of methane export to the atmosphere can occur via efficient subglacial drainage pathways. Our findings suggest that such environments have been previously underappreciated and should be considered in Earth’s methane budget.”Lamarche-Gagnon et al 2019

The ‘subglacial drainage’ process that’s melting glaciers and ice sheets described in the section on Antarctica, is also awakening microbes in ancient swamps and releasing methane from beneath Greenland. Antarctica is many times larger than Greenland and was once covered in lush forests, so is likely to have very large areas of permafrost.

“Several orders of magnitude more methane has been hypothesized to be capped beneath the Antarctic Ice Sheet than beneath Arctic ice-masses. Like we did in Greenland, it’s time to put more robust numbers on the theory.” Lamarche-Gagnon 2019

Fig. 2: “Parts of the Russian Arctic have experienced record-breaking high temperatures in recent weeks. This heat map — produced using data from a European Sentinel-3 satellite — shows air temperatures of up to 45°C in some places on 19 June. The heat has been linked to thawing permafrost, widespread wildfires, and swarms of tree-eating moths.” (Image: European Union, Copernicus Sentinel-3)
Fig. 3: Image from the 2021 feature in the journal Nature: ‘How microbes in permafrost could trigger a massive carbon bomb’. Click on the image to read the full story (Image: Nature |Sources: Data from Permafrost CCI; J. OBU et al. Data set at CEDA Archive https://doi.org/ghjkb2 (2020)
Fig. 4: 2019 September issue of National Geographic. Another stunning image from the photo essay by Katie Orlinsky that revels just a very tiny portion of permafrost exposed in the Siberian tundra at the Batagay ‘megaslump’. Click on the image to be taken to the story. Fig. 4 is a photograph at ground level.
Fig. 5: Note the trees at the top are large mature confers. A solitary person is standing a the edge of the cliff just to the right of orange vegetation hanging over the edge. Click on the image to be taken to the story.

Burning ice: methane clathrates

“Here we are. It’s 2020, and [atmospheric methane] is not only not dropping. It’s not level. In fact, it’s one of the fastest growth rates we’ve seen in the last 20 years.”  Drew Shindell, Duke University

Methane clathrates, also called methane hydrate, hydromethane, methane ice, fire ice, natural gas hydrate, or gas hydrate, is composed of methane trapped and frozen within a crystal structure of water, forming a solid that looks like ice but is highly flammable (Fig. 5).

Once thought to exist only in the frozen outer parts of the Solar System, it turns out to abundant in permafrost and beneath the ocean floor.

The USGS regard methane clathrates as fossil fuel resource; one cubic metre of methane hydrate produces between 163-180 cubic metres of natural gas (so the explosive potential is also high). While they have identified the risks of mining it…

The result might be gas blowouts, loss of support for pipelines, and sea-floor failure that could lead to underwater landslides and the release of methane from hydrates.”  – USGS

…the prospect of so much cheap gas is hugely appealing, especially as the Arctic is becoming increasingly accessible as more sea ice melts each year.

‘Tipping points’ are being exceeded in large areas as the Arctic Ocean also experiences record breaking temperatures for extended periods (Fig. 6).  Videos 3 & 4 explore, amongst other impacts, how methane erupts due to melting permafrost.

In shallow coastal waters and lakes, methane bubbles to the surface and escape directly into the atmosphere
(top image of Video 3; link to the peer-reviewed open access paper by Shakova et al.) In deep waters, the methane dissolves before reaching the surface. On the land and underwater, these abrupt explosive ‘burbs’ are forminglarge craters (Figs 3, 4, 7 & 8).

Fig. 6: Arctic temperature anomalies across the Arctic ocean and coastlines 13 May 2020. Temperatures are in Centigrade. (Image: Computer model simulation (Karsten Haustein)/ Washington Post 14 May 2020) This extreme warming continued into June (Fig. 1) and again in March 2022.
Fig. 5: Methane clathrate or hydrate is, like all fossil fuels, highly flammable. (Image: NASA GISS)
Fig. 7: Methane eruptions produce craters or ‘pingoes’. These were uncommon until around 2015 (Image: Prof. Vasily Bogoyavlensky / Siberian Times)
Fig. 8: Methane-eruption craters are now appearing across wide stretches of Siberia (Image: Encyclopedia Environment)

Video 3: Explains the processes that formed methane clathrates, why they are now melting, and the implications.

Video 4: Explains that large scale melting of clathrates in 2020 after Siberia experienced temperatures up to 45C (Fig. 6).

Video 5: IPCC State of the Oceans and Crysophere (7 minutes)

Video 6: IPCC State of the Oceans and Crysophere (56 minutes)

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