Geoengineering Approaches For Mitigating Methane Emissions  

Jamais Cascio has another post on geoengineering, this time looking at recent reports on methane emissions from the melting permafrost - Methane: It's Not Just From Your Cheeseburger. The interesting new take out is that most CO2 oriented geoengineering approaches won't work to mitigate large volumes of methane released into the atmosphere, which narrows the solution space considerably.

So that 50 gigatons of methane? That's the equivalent of 3600 gigatons of carbon dioxide, in terms of greenhouse effect.

To put that into comparison: the Earth's atmosphere holds a total of about 3000 metric gigatons of carbon dioxide.

This would more than double the concentration of CO2e in the atmosphere.

So this is not just huge, it's really freaking huge.

There's still nothing conclusive showing an overall increase in atmospheric concentration at this point, though, so hopefully that means that we haven't seen a catastrophic level of release (yet).

As I said, we still don't know if this is the methane hydrates beginning to melt. If it is, then even going to zero CO2 emissions now won't do a damn thing. Ocean thermal inertia will keep the temperatures up undersea for a good while, even if we stopped all carbon outputs now. Thermal inertia alone would keep us warming on land for a couple of decades, too, after we zero out, but that's comparatively less catastrophic than the hydrates.

Albedo-modification geoengineering (stratospheric sulfates, "space mirrors," that sort of thing) won't do much to change ocean temperatures in a short enough period to stop hydrate melts. At best, it would moderate atmospheric temperatures enough to stave off some of the most disastrous effects of a temperature spike. It seems highly likely to me that this is going to be a major point of political and scientific debate in the next few years, and we'll probably see some early attempts by early in the next decade.

CO2 sequestration geo (iron or urea dumps in the ocean, bioengineered supertrees, that sort of thing) won't do a damn thing about methane, even if it worked.

Probably the only possible geoengineering response with a direct impact on the methane would be some kind of in-situ methane conversion to CO2, either with chemistry or with methanotrophic bacteria.

It's hard to imagine a geoengineering project gone wrong that would be worse than a methane hydrate melt; a big methane hydrate event appears to be connected to one of the largest extinctions in geological history (bigger than the KT event killing the dinosaurs). 90+% of all species gone.

I've made it abundantly clear that I don't think geo is a good idea. It's a pretty damn crazy idea, in a lot of ways. But if this methane report is as bad as it looks to be, crazy ideas may be all that we have left.