Siberian permafrost is releasing ancient carbon much faster than previously thought
WHO: J. E. Vonk, L. Sánchez-García, B. E. van Dongen, V. Alling, A. Andersson, Ö. Gustafsson (Department of Applied Environmental Science (ITM) and the Bert Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden)
D. Kosmach, A. Charkin, O. V. Dudarev (Pacific Oceanological Institute, Russian Academy of Sciences, Vladivostok, Russia)
I. P. Semiletov, N. Shakhova (Pacific Oceanological Institute, Russian Academy of Sciences, Vladivostok, Russia and International Arctic Research Center, University of Alaska, Fairbanks, Alaska)
P. Roos (Risø National Laboratory for Sustainable Energy, Roskilde, Denmark)
T. I. Eglinton (Geological Institute, ETH-Zürich, Zürich, Switzerland)
WHAT: Measuring and calculating the carbon released from thawing and eroding permafrost in far northern Russia
WHEN: 6 September 2012
WHERE: Nature, Vol 489, 137-140
Those of you who read the recent Bill McKibben article in Rolling Stone magazine about the planet’s atmospheric carbon budget will know ~565 Gigatonnes is the amount of carbon pollution that humans can still burn and hope to avoid catastrophic climate change. Beyond that, we’re playing Russian roulette with extra bullets loaded.
Why am I talking about Rolling Stone when this paper is talking about Siberia? Well, the researchers for this paper went to far northern Russia to work out how much coastal Siberian permafrost is being eroded away, releasing the carbon into the atmosphere and spending our ever shrinking carbon budget.
The Arctic permafrost in Siberia holds ~1,000 Gigatonnes of carbon frozen on land, ~400 Gigatonnes of coastal carbon and ~1,400 Gigatonnes of sub-sea carbon. So if this permafrost starts thawing and releasing carbon at a great rate, we humans have totally bust our carbon budget and the future is looking pretty horrifying; much like the greenhouse extinction from last week’s post.
So is it thawing out? And how fast?
The Island of Muostakh in the north of Russia has been eroding at a rate of up to 20m per year, and this is where the researchers went to try and measure the amount of carbon that is being released into the atmosphere.
They used a dual carbon-isotope mixing model solved with a Monte Carlo simulation strategy, which is sadly not a really tasty sounding desert, but a way of working out which carbon isotopes are from plankton, topsoil or old carbon which is the stuff they’re interested in (they used 13C and 14C isotopes for those playing at home).
Through the isotope analysis they found a coastal permafrost carbon release of 22 Megatonnes (.022 Gigatonnes) of carbon per year from erosion. Additionally they estimate that 66% of the old carbon that is washed into the ocean degrades downstream and is released into the atmosphere instead of sinking to the sea floor. Previous research had thought that carbon from coastal erosion washed into the ocean without releasing into the atmosphere.
Once you combine the carbon eroded with the 66% downstream degradation, the total atmospheric release is 44 Megatonnes (.044 Gigatonnes) of carbon per year which is much larger than the previously estimated 4 Megatonnes of carbon per year. This large difference may be because of methods used in previous research, unaccounted for changes in coastal elevation (the higher the cliff, the harder for the waves to reach it) or not counting the sub-sea degradation.
Either way, the idea that we may be under-counting the amount of carbon released from thawing and eroding Siberian permafrost has some serious implications for all of us. We are currently polluting the atmosphere with carbon at a rate of 31.6 Gigatonnes per year and rising. As we continue to burn carbon, the permafrost in Siberia will thaw and erode faster, increasing from the current rate of .044 Gigatonnes per year.
We are quickly running out of time and atmospheric space to stop runaway climate change. If even half the sub-sea permafrost is released as atmospheric carbon, we’ve surpassed 565 Gigatonnes. Hopefully the increased and continued thawing of the Siberian permafrost isn’t the bit that busts our carbon budget.