There’s a book I got years ago – I think it might have been a stocking stuffer – called The Miseries of Human Life. The book was originally printed in 1806, and dwells not on true horrors like war and poverty, but specifically on the minor miseries of our lives. Those things that seem to afflict us all, simply for the crime of being human. It’s things like hangnails, or food that slips out from under your knife when you try to cut it. It’s people conversing across you at a bar, or being suddenly overcome with sleepiness while listening to someone talk, even though you’re genuinely interested, and respect the speaker.
One such misery of modern life is the fact that every speck of good news about climate change seems to fall into the category of “well, it’s still bad, but it’s not as bad as we feared”. We never get unambiguously good news. I hope that will change in my lifetime, but as it stands, it’s a minor frustration, like a sock that keeps slipping down your heel as you walk.
So, there’s good news! It seems that methane emissions from melting permafrost aren’t as bad as we feared!
Permafrost runs like a frozen belt of soil and sediment around Earth’s northern arctic and sub-arctic tundra. As permafrost thaws, microorganisms are able to break down thousands of years-old accumulations of organic matter. This process releases a number of greenhouse gases. One of the most critical gasses is methane; the same gas emitted by cattle whenever they burp and fart.
Because of this, scientists and public agencies have long feared methane emissions from permafrost to rise in step with global temperatures. But, in some places, it turns out that methane emissions are lower than once presumed.
In a comprehensive new study by a collaborative from the University of Gothenburg, Ecole Polytechnique in France and the Center for Permafrost (CENPERM) at the University of Copenhagen, researchers measured the release of methane from two localities in Northern Sweden. Permafrost disappeared from one of the locations in the 1980’s, and 10-15 years later in the other.
The difference between the two areas shows what can happen as a landscape gradually adapts to the absence of permafrost. The results show that the first area to lose its permafrost now has methane emissions ten times less than in the other locality. This is due to gradual changes in drainage and the spread of new plant species. The study’s findings were recently published in the journal Global Change Biology.
“The study has shown that there isn’t necessarily a large burst of methane as might have been expected in the wake of a thaw. Indeed, in areas with sporadic permafrost, far less methane might be released than expected,” says Professor Bo Elberling of CENPERM (Center for Permafrost), at the University of Copenhagen’s Department of Geosciences and Natural Resource Management.
This is good news. Methane doesn’t last as long in the atmosphere as carbon dioxide, but it’s much more powerful as an insulator in our atmosphere, and the reason climate change is so dangerous is the speed at which it’s happening. Anything that means it’s moving slower than it could be is good for us. It means that we have just a little bit more time to act.
What’s even better is the reason why the researchers think there’s less methane production:
According to Professor Elberling, water drainage accounts for why far less methane was released than anticipated. As layers of permafrost a few meters deep begin to disappear, water in the soil above begins to drain.
“Permafrost acts somewhat like the bottom of a bathtub. When it melts, it’s as if the plug has been pulled, which allows water to seep through the now-thawed soil. Drainage allows for new plant species to establish themselves, plants that are better adapted for drier soil conditions. This is exactly what we’re seeing at these locations in Sweden,” he explains.
Grasses typical of very wet areas with sporadic permafrost have developed a straw-like system that transports oxygen from their stems down into to their roots. These straws also act as a conduit through which methane in the soil quickly find its way to the surface and thereafter into the atmosphere.
As the water disappears, so do these grasses. Gradually, they are replaced by new plant species, which, due to the dry soil conditions, do not need transport oxygen from the surface via their roots. The combination of more oxygen in the soil and reduced methane transport means that less methane is produced and that the methane that is produced can be better converted to CO2 within the soil.
“As grasses are outcompeted by new plants like dwarf shrubs, willows and birch, the transport mechanism disappears, allowing methane to escape quickly up through soil and into the atmosphere,” explains Bo Elberling.
The combination of dry soil and new plant growth also creates more favorable conditions for soil bacteria that help break methane down.
Like I said – less methane is good even if it’s just being replaced by CO2. Ready for the even better news? There doesn’t seem to be a big increase in CO2 either.
“When methane can no longer escape through the straws, soil bacteria have more time to break it down and convert it into CO2,” Bo Elberling elaborates.
As a result, one can imagine that as microorganisms reduce methane emissions, the process will lead to more CO2 being released. Yet, no significant increase in CO2 emissions was observed by the researchers in their study. This is interpreted as being the result of the CO2 balance, which is more heavily determined by plant roots than the CO2 released from the microorganisms that break down methane. Crucially, even though methane ends up as CO2, it is considered less critical in climate change context as methane is at least 25 more potent greenhouse gas as compared to CO2.
The article goes on to talk about the role precipitation could play in affecting this – more water probably means more methane – but I find this genuinely encouraging. It’s another indication that if we can get our act together, the ecosystems around us will probably help us in our efforts to stabilize the climate. This is also information that we could put to use in trying to mitigate permafrost emissions in other areas, as we look to engaging in stewardship of a rapidly changing planet.
It’s worth remembering, sometimes, that the indifference of our universe means that sometimes things work out in our favor in ways we didn’t expect. Obviously that’s no guarantee of a good outcome, but it does give me more motivation to do what I can now, so that as those bits of good luck come our way, we’re better able to make use of them.
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