Terraforming Earth IV: The Question of Methane
Terraforming Earth is the effort to use large-scale engineering to affect geophysical processes in a way to avert radical changes to the environment -- that is, to make Earth "Earth-like" again. I touched on the idea first here, expanded on it here, and explored some of the more philosophical questions here. In all of these pieces, however, you'll note that this terraforming work is thought to be an option for some time down the road, after other solutions are exhausted. There's no argument in those three essays that we should start large scale engineering efforts now.
Today's email brought news that should make us think hard about how soon we might want to bring such efforts to bear.
Many of you sent me links to the article in today's Guardian UK newspaper (linking to a New Scientist article) outlining a "tipping point" in the Siberian arctic: the permafrost appears to be melting. This is happening due to a combination of natural arctic temperature cycles, global warming (Siberia is warming faster than any other place on Earth), and a feedback effect from melting snow -- the darker ground absorbs more heat, resulting in faster melting of adjacent permafrost. Siberian permafrost covers a million square kilometers of ground that's largely peat bog; the peat has been producing methane for centuries, but that methane has been trapped under the permafrost. With the permafrost melting, the methane would be released into the atmosphere, accelerating global warming by a substantial amount. How quickly the methane would be released remains an open question -- would it take years to release it all? Decades? A century or more? Clearly, this situation demands a great deal more study.
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.
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The idea of the emerging
The future is not written in stone, but neither is it unbounded. Our actions, our choices shape the options we'll have in the days and years to come. We can, with all too little difficulty, make decisions that call into being an inescapable chain of events. But if we try, we can also make decisions that expand our opportunities, and push out the boundaries of tomorrow.
The Earth's environment, particularly its climate, is not a linear, obvious-cause and immediate-effect system. This has a number of implications, but the one that troubles many of us who pay close attention is the resulting potential for "phase change" shifts in the climate system, where seemingly-small perturbations lead to a major change in how the climate behaves (the classic example of this kind of change is a pile of sand with grains dropping down on the peak; some will slide down, some will stack up, but eventually the entire peak will collapse, radically changing the shape of the pile). As we develop the tools and techniques to better understand the overall global climate and ecological system, these "tipping points" should be at the top of our list of processes to identify and, if at all possible, defend.