More methane from defrosting permafrost

One reason that predicting climate change is so difficult and research-intensive is that the whole planetary system is such a complicated mess of geochemical boxes and fluxes. A geochemical box is shorthand for some definable place that holds massive amounts of some particular element or compound. Fluxes move compounds from one box to another. You can think of the ocean as one big geochemical box for water, with evaporation being the biggest flux moving water out of the ocean and into the atmosphere. Rivers and seeping groundwater flux water back to the ocean, eventually. If you can add up all the fluxes and all the boxes, you can make a pretty good model of how the water cycle works.

The problem is much harder with climate. Water is easy to track. But climate is not a thing, it’s the sum of thousands of different things, each moving in and out of dozens of boxes all the time. Carbon dioxide, water vapor, methane, CFCs, sunlight, oceans, trees, rocks, ice, blah blah blah. An entire planet is a messy, complicated business, and we talking apes have only recently started to seriously try and understand how our planet is put together.

Take permafrost. If you go up into Canada or Siberia you’ll find miles and miles of miles and miles of permafrost just under your feet. More specifically, under the freezing muck that sits under the pretty fluffy moss that you might not think is so pretty after about thirty-five million mosquitoes and black flies erupt from said moss to feast on your precious bodily fluids. Anyway. If you dig into the muck, your shovel will hit solid ice. That’s permafrost.

Permafrost is interesting because sometimes it can melt to reveal whole wooly mammoths, or old huts made from mammoth bones by primitive but sexy Jean Auel characters. Mostly today, though, permafrost melts to reveal compacted, rotting plants. Lots and lots of compacted, rotting plants. And bubbling up like a bubbling crude from these miles and miles of rotting compacted plants is methane.

Methane is one component of natural gas, and if we could take all that methane from unfrozen, rotting Russian and Canadian bogs, we could power the world for some time. However, until someone invents a way to cheaply cover all of the boreal Arctic with plastic sheets and pipes, we’re out of luck on that score. But as a consolation prize, we get to have twice as much global warming! Isn’t that exciting?

A recent study by climate scientists from Russia, Canada, the US, UK, EU and Australia reports that there is probably going to be a lot more methane coming out of the Great Rotting North during the next century than most people assumed until now.

(T)he three-year study concluded that accounting for carbon stored deep in the permafrost more than doubles – to more than 1500 billion tonnes – previous estimates of the world’s high-latitude carbon inventory.

Methane is a global warming problem because it is a greenhouse gas, and molecule-for-molecule about twenty times more potent than carbon dioxide at trapping infrared energy. As the north thaws, more methane reaches the atmosphere and warms it more, leading to more melting of the ice and more methane release. Eventually the system will reach an equilibrium, but not before massive amounts of compacted peat rot into the air. Unfortunately, even at that point there won’t be much soil to use for farming; boreal soil is nutrient-poor and stony.

Has this happened before? Almost certainly, probably lots of times over the past few million years, as a result of natural climate changes and retreating glaciers. I stipulate that because it’s almost certainly going to be the first thing out of the global warming deniers’ mouths (they’re not a creative lot, except when it comes to lying). But then you can ask them how many of those times coincided with a sprawling human civilization of over seven billion people who were acutely dependent on a global infrastructure of just-in-time commerce and mechanized high-yield agriculture. (Hint: it’s equal to the number of times global warming deniers have been right.)


~ by Planetologist on September 18, 2008.

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