I haven’t checked in with our second favorite greenhouse gas, methane in a while, so I hopped over to the NOAA ESRL GMD Carbon Cycle – Interactive Atmospheric Data Visualization page, did the usual bunch of clicking, and here’s what I saw:
Notice anything, how shall I put this, outstanding about the graph? Perhaps the skyward spike in observations right at the end of the data series?
Yeah, that’s what I thought.
OK, for everyone who’s new to the site, including those who just accidentally stumbled in through the Google side door while looking for True Blood rumors, let me give you the quick list of reminders on methane:
- Methane is a pretty potent greenhouse gas, between 20 and 25 times more potent than CO2, in fact, depending on who’s counting. Methane doesn’t hang around in the atmosphere nearly as long as CO2 does, but while it’s there it contributes a lot more to warming than would an equivalent amount of CO2. The agreed-upon standard is to use a 100-year window for methane’s CO2 equivalency, which is what’s used for those 20 to 25 values. Given that we have a steady stream of methane emissions from land fills, farms animals, natural gas leaks, and possibly other, much more terrifying sources, that 20 to 25 number is uncomfortably interesting.
- The first of those two main terrifying sources of methane is hydrates, basically methane trapped in tiny icy cages under water. Hydrates are scary because there’s a hell of a lot of them scattered around the globe, and we’re not exactly sure when we’ll see enough warming to start liberating them in large enough quantities to kick climate change into high gear. There have been numerous reports of scientists finding localized methane releases from hydrates, some pretty dramatic, but as far as I know nothing to panic over yet.
- The other terrifying source of methane is the immense stores of it in permafrost in the land around the Arctic. When permafrost forgets the “perma” part, it defrosts and releases whatever it contains, which is often vegetatin that decays, producing CO2 and methane. As with hydrates, there’s a mind blowing amount of frosty carbon just waiting to be transmogrified into greenhouse gases, and we’ve seen numerous reports of permafrost melting and emitting seemingly large amounts of methane, but there’s no evidence yet of anything from an Irwin Allen disaster movie.
- For all the talk about tipping points and abrupt climate change, large-scale releases of methane from hydrates and/or permafrost will likely happen over a time frame that’s slow in human terms — decades to centuries — even if abrupt on a geological scale. But remember that not all of that methane has to be released for things to get seriously ugly. Even a small portion of it would be very unwelcome.
- My understanding is that we’re not really sure why we get the roller coaster effect seen in the graph. Why the surge from roughly 1986 until 1999? Why the ensuing lack of growth to about 2006, followed by another surge, complete with the current spike? The last few years’ rise is thought to be from various wetlands around the globe and not permafrost, but again, I don’t think there’s a solid scientific consensus regarding the major trends in that graph. Similarly, the immense fires this summer in Russia might have played a role in the spike — methane is a byproduct of incomplete combustion of biological material — but I haven’t seen any statement to that effect. (If anyone here knows something more definitive, please leave a comment.)
- We should not read anything particular into these numbers, especially when we see a spike like that in the latest observations; we should instead wait for results from real scientists doing real science. Having done my responsible bloggerly duty and delivered that prudent warning, I have to admit that I would feel much better if the blasted observations would stop going up.
- I suggest you remain on the outlook for wackaloon pronouncements about methane, as in Monckton’s recent statement:
In fact, melting permafrost is nothing but a good thing: despite the lurid tales of methane trapped in the permafrost and waiting to erupt and give the planet a fever, methane is really a non-issue now that the Russian pipeline to Europe has been repaired. There has been no noticeable increase in atmospheric methane since the repairs were completed in the year 2000. If the permafrost were to thaw, billions of acres of productive agricultural land would become available.
The less said about that howler, the better.
- So, how worried should we be about methane? I think it’s clear that:
- Given our global policy paralysis regarding CO2 emissions, we certainly don’t need yet another source of radiative forcing adding to the accumulating problem. That methane trend line continuing to rise is unequivocally a bad thing.
- We really do seem to be playing Russian roulette when it comes to hydrates and the permafrost. Will they start to contribute in a major way to climate change next year or do we have another 50 years of breathing room? As best I can tell from reading everything I can find on the topic, I don’t think anyone has more than an educated hunch about it. But if those sources do start to kick in well above their current levels, we’ll have an almost unimaginably big problem on our hands. In that scenario we wouldn’t be able to stop those leaks from hydrate deposits and/or permafrost, and even a crash effort to reduce CO2 emissions won’t help, thanks to the very long atmospheric lifetime of that gas. Short of actively removing CO2 from the atmosphere, every ton of it we emit is an irreversible step closer to hideous human impacts from climate change, including ocean acidification. Love is fleeting, but CO2 is effectively forever.
- It would be an exceedingly good idea to find a way to reduce our CO2 emissions a lot, and soon. The extra warming they trigger only increases the probability that methane will turn an already bad situation into a runaway problem.
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