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The Finnish carbon sink project Hiilipörssi ("carbon exchange") has this tagline on their English information page:

Did you know that restoring peatlands is one of the most cost-effective ways to mitigate climate change?

The project is supported by the Finnish Association for Nature Conservation which is the leading Finnish environmentalist organization, as well as the philantropic foundation Koneen Säätiö, and has received coverage from the Finnish public broadcasting company YLE eg. here.

I do not question that a living swamp is a very effective carbon sink. However, the anaerobic environments present in swamplands also produce significant amounts of swamp gases including methane, another greenhouse gas. The United States Environment Protection Agency lists methane's global warming potential as 28-36 over a period of one hundred years (whereas carbon dioxide is the baseline of 1) taking into account methane's shorter lifespan but also its greater energy absorbtion and the fact that methane is a precursor to ozone, another greenhouse gas.

Considering the marsh gas emissions of a peat bog, is restoring peat bogs beneficial in slowing down climate change?

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Wikipedia cites an estimate from a Finnish source that 6 billion tonnes of carbon are sequestered in the peat swamps of Finland. According to an estimate of world carbon emissions, that is roughly equivalent to nearly 2/3 of average annual emissions over recent years. So in that sense, the amount of carbon sequestered in peat is quite significant, and it makes sense that conserving peatlands should have a positive effect on climate.

It is certainly true that peat swamps emit greenhouse gasses, including methane, which has to be factored in. However, according to the International Peatland Society,

When considering the role of peatlands in atmospheric GHG balances, it is important to consider that they have taken up and released GHGs continuously since their formation and thus their influence must be modelled over time. When this is considered, the effect of sequestering CO2 in peat outweighs CH4 emissions. [emphasis added]

There is a metanalysis of studies that looks in more detail at the complexity of calculating net climate impacts of northern peat lands management. Keeping peatlands wetter is likely to increase methane production, but preserve overall carbon sequestration over time. Overall then, it may or may not be true that "restoring peatlands is one of the most cost-effective ways to mitigate climate change" as quoted in the original post. That may be an overstatement relative to what we really know, even if it is likely a good thing to do.

  • This answer seems to be about conserving peat bogs. What about restoration? – kviiri Apr 1 at 3:47
  • @kviiri Can you explain what the distinction would be in this context? Unless someone is talking about putting peat back into the ground after its been dug up, I think "conservation" and "restoration" of peat bogs would effectively be the same thing. – Brian Z Apr 1 at 13:15
  • What I mean is, the alternative for conserving the peat bog is using the peat, assumedly for fuel, which causes a (relatively) sharp increase in carbon dioxide in the atmosphere. Conserving the bog might be worthwhile just to avoid this spike, even if its methane output would outweigh its carbon dioxide output. Whereas for a restored bog, the spike has already been caused, removing that part from consideration. – kviiri Apr 1 at 13:34
  • To make a crude analogy: not mining and burning coal might be a smart strategy to fight climate change, but that doesn't guarantee making carbon dioxide into coal and hiding it underground is. – kviiri Apr 1 at 13:49
  • I would add that peat bogs are a one time benefit. Restore one you remove X carbon, which is useful, but no were as useful as lowering carbon emissions via means like decreasing energy use or more energy efficient technology which lowers emissions over time having a cumulative effect that will eventually add up to more then the flat X removed by building a bog. – dsollen Apr 2 at 15:53

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