Melting permafrost

Allie Wilkinson writing in ArsTechnica brings us some bad news:

Evidence from caves in Siberia indicates that a global temperature increase of 1.5° Celsius may cause substantial thawing of a large tract of permanently frozen soil in Siberia. The thawing of this soil, known as permafrost, could have serious consequences for further changes in the climate.

Up until new we have been exceptionally lucky in that about half of the carbon we have emitted into the atmosphere has been absorbed by the biosphere, however at some point our luck will run out and various carbon sinks will stop absorbing carbon and start releasing it.

Comments:

  1. Great article, cheers Dan. Related story at New Scientist.

    This really drives home a sinking realisation. While pretty much all our political and research structures continue to develop around a 2 degree target, the reality is turning out to be very different. As a researcher, I see the various UK funding councils fitting into that 'how do we fix the climate problem' way of thinking. This is leaving us with no systematic research agenda to address what are looking to be fairly likely outcomes, including a global permafrost hand-grenade thrown into the climate system.

    Our research institutions have foresight enough to see the change in currents ahead but they're ignoring the massive waterfall and the drop beyond.

    That's a huge generalisation, I'm sure there are many working on these kind of what-ifs. My point is, those what-ifs need a much more strategic, broad attack. We are managing to push ourselves towards territory that, really, not that many people bothered to consider in depth because no-one thought we'd be this stupid. We are this stupid. So we have mainly only vague statements like "may threaten the very fabric of civilisation" etc.

    For anyone who thinks our civilisation has some value worth fighting for, we're going to have to do a lot better than that. If we are going to be this stupid, can we at least do it intelligently?

    • Dan O., I was pleased that the Ars and New Scientist articles did not flog the tundra-carbon-feedback-bomb panic, which does not have much support among scientists. I am a bit chastened that you still read it in there.

      Note that at the link you provide are the words "As for the methane that could be released into the atmosphere, Schuur estimates that emissions will be equivalent to between 160 and 290 billion tonnes of carbon dioxide. That sounds like a lot, but is little compared to the vast amount humans are likely to emit, says Lenton. 'The signal's going to be swamped by fossil fuel [emissions]'. He says 'the dangers of the permafrost greenhouse gases have been overhyped, particularly as much of the methane will be converted to carbon dioxide by microbes in the soil, leading to a slower warming effect.'"

      We are being quite stupid indeed. But this particular aspect is a concern that is widespread in the public but not among scientists. It's not quite as baseless as the "Gulf Stream shutdown" one was a few years back. But both concerns were extremely overdrawn and basically inaccurate.

  2. "I am a bit chastened that you still read it in there."

    It turns out I didn't read it properly or indeed engage my brain very well. Somewhere in my skull, the radical change in landscapes described got mixed up with the permafrost bomb idea and I short-circuited. Given I was talking about responding intelligently, I'm just gonna nip off and give myself a good kicking.

  3. You may as well know what the Weather Channel is presenting:

    http://www.youtube.com/watch?feature=player_embedded&v=2IjG-OgW99s

  4. There's this 39 page UNEP report (PDF) from November 2012 that got some airing e.g. at Science Daily. Note the list of papers on p.10 of the report.

    There are massive uncertainties: "The release of CO2 and methane will persist for a hundred years or more after atmospheric CO2 stops increasing (Figure 22), influencing the climate system for centuries (Koven et al. 2011, Schaefer et al. 2011). The decay of thawed organic material is slow because the soil will still be cold and wet (Koven et al. 2011, Schaefer et al. 2011; Schneider von Deimling, 2012). Also, the thawing of permafrost may persist for decades or even centuries after anthropogenic greenhouse gas emissions have stopped (Schaefer et al. 2011)." (p.19)

    And from the same report here's a list of papers with Gt Co2 equivalent estimates for 2100, 2200 and 2300.

    So: not a permafrost bomb, but definitely some juggernaut potential there? If human co2 emissions were reduced to zero but permafrost emissions have got going, will there still be a permafrost carbon feedback as the UNEP report implies? Will there be enough other feedbacks / inertia to keep it going for several centuries? What role for negative feedbacks? Plants and peat are mentioned.

    And, really, how the bejeesus are we meant to think about these kind of timescales?


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