More on peat bogs

This National Geographic article givsx you much more depth and info than the newspaper articles.

Brenda Ekwurzel is a climate scientist with the Union of Concerned Scientists in Washington, D.C. She said the West Siberian Lowland indeed falls within a hot spot but added that whether thawing peatlands will accelerate global warming remains an open question.

Ekwurzel noted, for example, that while the peatlands have the potential to release large quantities of carbon dioxide and methane, changes in the soil and groundwater could lead to increased tree growth, which acts as a carbon sink.

“If it turns out the net impact is increased carbon dioxide and methane emissions to the atmosphere, this would lead to warming and subsequent feedback or amplification cycles,” she said.

Smith, the UCLA geographer, is now trying to determine what will happen in western Siberia if temperatures continue to rise, causing the currently frozen peatlands there to thaw and dry out.

Such a scenario would certainly cause the peatlands to decompose and release vast amounts of the carbon dioxide that has been accumulating for the last 11,500 years. However, peat cores taken throughout the region show no evidence for such catastrophic warming in the past, despite evidence that the peat has previously undergone warming episodes.

“That’s why it is such a debate,” Smith said.

WorldChanging discusses terraforming the earth.

It’s important to note that the source of this story is not a peer-reviewed, multiply-confirmed piece of research in Nature, Science or the PNAS. It’s an article in New Scientist about a presentation from a group of researchers just back from Siberia. This doesn’t mean that the findings are wrong, only that we should be skeptical until they’ve been confirmed. But that such permafrost melting would result in the release of abundant methane is not a new theory, and New Scientist notes that independent research points to methane “hot spots” already forming in the region.

For the moment, then, let’s assume that the article is generally correct: the permafrost melt is getting faster, and the boggy ground beneath is releasing its pent-up methane. There are two important things to know about this situation: the amount of methane that would be released is projected to be in the multi-gigaton range — one source says 70 billion tons, another says “several hundred” billion tons; and methane is 21 times more powerful a greenhouse gas than carbon dioxide. In essence, the release of (say) 100 billion tons of methane would be the functional heat-trapping equivalent of 2.1 trillion tons of CO2. To put that number into perspective, the total annual output of greenhouse gases from the US is about 7 billion tons of CO2 equivalent.

This is a big deal.

But there’s actually a third important thing to know: although CO2 takes upwards of a century to cycle out of the atmosphere naturally, methane (CH4) takes only about ten years. Why the difference? Chemical processes in the atmosphere break down CH4 (in combination with oxygen) into CO2+H2O — carbon dioxide and water. In addition, certain bacteria — known as methanotrophs — actually consume methane, with the same chemical results. These processes have their limits, however; an abundance of methane in the atmosphere can overwhelm the oxidation chemistry, making the methane stick around for longer than the typical 8-10 years, and the commonplace methanotrophic bacteria evolved in an environment where methane emerges gradually.

These are pretty much the only two natural methane “sinks.” There are a few small-scale human processes that can make use of methane (for the production of methanol for fuel, for example) and function as artificial sinks, but such efforts would be hard-pressed to capture methane released across nearly a million square kilometers. This, then, is where we start to consider the option of planetary engineering.

Both of the natural processes are, in principle, amenable to human intervention. The oxidation of methane into CO2 and water is a well-understood phenomenon, and relies on the presence of OH (hydroxyl radical); upwards of 90% of lower atmosphere methane is oxidized through this process (PDF). But OH is something of a problem chemical, in that it’s also a key oxidation agent for many atmospheric pollutants, such as carbon monoxide and NOx. Although we could produce OH to enhance the natural chemical oxidation process, the side-effects of pumping enough OH into the atmosphere to oxidize all of that methane would be unpredictable, but almost certainly quite bad.

If you think I’m suggesting this option in a casual or flippant manner, you need to read Terraforming Earth essays one, two and three. Planetary engineering — including the widespread release of genetically modified organisms to combat atmospheric changes — should only be considered when more readily reversed and managed solutions are no longer available or functional. In the case of the Siberian methane, the more cautious options are extremely limited. We’re no longer in a position to stop the melting, even by ceasing all greenhouse gas production today; the temperature increases we’re seeing now are the results of greenhouse gases put into the atmosphere decades ago.

This is cheering. Even if it would help, the odds that the threat will be avoided by governments getting serious about reducing emissions seem much too slim. So it’s nice to be reminded there’s a third possible scenario where things turn out alright.

I wonder, I wonder if such a scheme, possibly quite risky, would meet as much resistance by sceptics and the like, as reducing emissions?

…My quotes may seem DeLongian, but I’m only quoting a small portion. Read the whole thing, and thank god for WorldChanging.

4 thoughts on “More on peat bogs

  1. I wonder, I wonder if such a scheme, possibly quite risky, would meet as much resistance by sceptics and the like, as reducing emissions?

    It was warmer, even much warmer, in the past. Ecosystems survived. We never poured free radicals to that extent in the atmosphere.

    Doing an unknown geochemical experiment to counter another geochemical experiment that is within precedented range whose consequences’ extent is unknown is insanely risky.

    We know how much warmer this planet may become in an extreme case. It would mean profound change, but it is mostly managable.

  2. “the odds that the threat will be avoided by governments getting serious about reducing emissions seem much too slim”

    I’m afraid you are all too likely to be proved right here, although I don’t think it is going to be fair to blame all this on governments, the people who elect them also have some part to play in the story.

    I can’t help but be struck by the similarities between the climatic issues and the demographic ones. In neither case do we seem capable of coming up with an adequate response.

    The time scales involved undoubtedly form part of the picture, as does the fact that the science needed to understand the problem is evolving in real time along with the problem itself (Hegel: the owl minerva flies only after dusk). In this case we may get a consensus on the underlying science in both issues only after it is too late to effectively to do much about the problem. Meantime politicians need to get elected, and focus on the here-and-now issues that voters want to know about. In this sense we have badly adapted political systems.

    Obviously in both cases we need to act before we have reached a consensus understanding (in the case of demography we still don’t know the long term TFR equilibrium settings, and we don’t know the underlying rate of extending life expectancy out into the future) and this will imply a certain level of risk and uncertainty in what we do.

    Unfortunately I don’t understand the fundamentaly science sufficiently to be able to assess the idea of using using genetically-modified forms of methanotrophic bacteria to act as a sink. The question would seem to be: “what else might happen?”, or be careful what you ask for.

    So, in the balance, and as a short-term stopgap, while we get a bit clearer what to do, I think it really would make sense to be putting in place a much more rigourous set of energy use controls than those we currently contemplate, difficult as that may be to achieve.

    Also, I’m still not sure whether the real issue will be global warming or global cooling (see comment on your other post).

    And yes, I am back from holiday, but no, I won’t be back to posting just yet :).

  3. I saw an interesting piece in either Sunday’s Times or Saturday’s Guardian (I forget which now) about a guy who has hit upon the idea of spraying salt into clouds. This, he argues, would make the clouds whiter, thus allowing them to reflect more sunlight. He thinks it would be very practical and (most importantly) fairly cheap to pump enough salt up there to balance out the amount of CO2 and methane we are pumping into the atmosphere.

    The article also had a pretty cool graphic of robot ships trawling the oceans, pumping salt into the atmosphere in much the way that steamships pump out steam.

  4. Methanotrophic bacteria would transform methane in carbon dioxide. Unless that process affects only airborne methane, it would be equivalent to burning methane as natural gas, without any useful work. A bad move I reckon.

    DSW

Comments are closed.