Home » Destabilised subsea permafrost & methane release risk | Igor Semiletov

Destabilised subsea permafrost & methane release risk | Igor Semiletov

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Nick Breeze

Climate journalist and host of Shaping The Future podcast.

Igor Semiletov | Arctic Methane Interview

This is the first in a miniseries discussing the ongoing work in the Russian Arctic talking to Dr Igor Semiletov, one of the lead scientists who has been studying the region for over twenty years. 

Old deep thermogenic pool

In assessing whether the potential for increased climate warming is a significant risk, scientists look at the size of the carbon pool and also the origin of the methane. 

In many cases where methane is produced from biogenic sources, such as animals and plants, it is created by microbes and although has the same global warming potential, it is created very slowly and is often broken down to CO2 before it reaches the atmosphere. 

The other source is thermogenic methane that occurs due to the decay of organic matter at high pressure and temperature. For these conditions to occur, the sediments where they are found are older and deeper.

In terms of the East Siberian Arctic Shelf, many scientists have believed that the methane emissions are from biogenic sources. This means they would be slower to form and overall a lesser risk to the global climate. 

Discussing the importance of these finding, Dr Semiletov said, ‘this is critically important to our understanding because before, scientists who work in this area, supposed that the source for hydrates is old biogenic carbon. We came to this conclusion in our previous publication published in Biogeosciences because most of the data indicated it was biogenic. Most of the data was taken from the shallow part of the Laptev Sea but some measurements was also taken from the outer shelf indicated was biogenic.’

After that we performed a long term study with our strategic colleagues from Stockholm University. We analysed triple isotopes of methane, more than one hundred samples and we did much more detailed study, and based on this new set of data we felt in conclusion that thermogenic methane dominates. 

Methane Seep sites

Semiletov defines two different scales of seep sites where methane is visibly seen reaching the surface: 

“We already mapped more than 2000 large seeps and megaseeps. By large seeps we mean bubbling methane release areas with a scale equal to hundreds of metres. Megaseeps, it is 1000 metres plus.”

NB: And how many megaseeps would you estimate there are?

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IS: I would imagine in the middle of the road… we have mapped more than 2000 large seeps but only 6 or 7 seeps that we call megaseeps. We try to revisit large seeps and megaseeps as often as we can because we have limitations of ship time. It is very expensive and we have restrictions.

But we have revisited all registered megaseeps and we have found that they are growing. Some of them are growing 3 or 4 times during 5 years. I mean they are increasing in horizontal scale. We are preparing for several papers on this. The dynamics of methane release and several megaseeps.

Call for extended research

NB: As you are sailing out in one line and you’re seeing this mega seep with thermogenic methane coming from a very big source below, so the conditions seem to becoming more equilibrated and more easier for the methane to escape. You obviously need more research, so you expect what you are seeing in 1 line must be going on all the way across. Are we talking about a mechanism for changing global climate in just one part of the ocean? Is this the underlying point?

IS: Yes and we call for increasing international collaboration because we study what we are doing now is international by nature and in the last 15 years plus we are working globally with our partners from Stockholm University and more than 15 universities from Europe and from US. Not much collaboration from the US now. 

We believe that the new brief for this collaboration should be extended. As you said, one cruise is just along one line and the East Siberian Shelf is 2 million square kilometres. We already measure 2 thousand large and mega seep areas, just using this line. 

So what can we do in one cruise, we can observe one, two, three four or five mega seeps at a time because it takes ship time and that is expensive. Now we have people and we have equipment but we are limited with ship time and, actually, we are limited with funding. We do what we can do but we have quite limited funding. It is never enough but this topic is international.

Controversial subject

The Siberian methane issue has been historically controversial with some scientists calling it out as alarmism based on unsubstantiated evidence. I address this with Semiletov later in the interview and have discussed it previously with his colleague Dr Shakhova. 

What makes their case very compelling is the amount of data they and their international collaborators are collecting that is being published in peer reviewed journals and is based on observations. Commenting on this he says:

‘Now we know that degradation of subsea permafrost is in progress and this causes destabilisation of hydrates and this massive methane release. But the scale of the methane that is there is still under debate and we are very careful because it not easy to publish what we have already published in Science and Nature because many people believe that it is an overestimation but what we publish is based on observations and proved by observations again and again.’

Call for support

Despite over 20 years of observational study with enormous datasets and a growing interest from scientific researchers around the world, the Russian team struggle to finance their work. In recent years, collaborations with their Swedish and other foreign partners, have enabled them to continue. 

Semiletov says that the response to their research in Russia has been positive but, like everywhere, competition for different funding sources is always tough. With Russia assuming the presidency of the Arctic Council this May, he hopes that their work will rise up the political agenda:

Semiletov: ‘I think under the umbrella of the Russian Presidency of the Arctic Council, that happens this May for two years, we can do a lot but we need to agree between countries at a federal government level, we need funding from different countries. 

I know that the Russian federal bodies, they are very positive to open the gate for international scientists to come and join us in this direction. But we need a debate and discussion and maybe the Arctic Council is a good place for the discussion and international coordination.

Of course we keep going with our partners, the Orjan Gustaffsson group, we will have new isotopic data, even what we have now, we have published only a tiny fraction. We are working altogether and our only limitation is funding.’

What do you need?

Nick Breeze: So if you are talking to the Arctic Council and they said tell us what you want and we will get you the budget tomorrow, what would you ask for?

IS: Well, we made some calculations and it is not huge money. We think that with 2 million euros a year we and do a lot. Two vessel operations which would help to jump in our understanding for what is going on. It is not a huge amount of money, not even for Russia but there is competition from many groups.

[END]

Should the Arctic Council, as well as individual nations, be funding this research – please share your view: Feedback link – 

This article has been created using extracts from recent interviews with Dr Semiletov. In part 2 I speak to Professor Orjan Gustafsson from the Department of Environmental Science at Stockholm University. 

Orjan has been visiting the East Siberian Shelf for many years working alongside an international group of scientists including the Russians. He discusses how research into the escaping methane  and thawing permafrost in the East Siberian Arctic Shelf should be greatly expanded considering the magnitude and changing stability of the carbon pool. He also suggests that this research could have enormous ramifications for how carbon budgets that inform policy, are calculated.

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