Over at The Volokh Conspiracy, Jonathan Adler notes that the NAS is starting to look into the possibility of geoengineering to roll back human changes in the climate. For those of you who haven’t heard, geoengineering is the process of deliberately changing the climate to compensate for the effects of greenhouse gases.
There’s no shortage of reasons it might not work. The most obvious is that climate is not fully understood as it is, and so massive alterations may have unintended consequences and make things worse. Especially if the methods of geoengineering result in permanent changes, this could be disastrous. It’s also true that no global change will impact each climatic region equally and so any geoengineering scheme will likely have at least some countries objecting to its use even in the abstract.
Those are fairly compelling objections, though I should also mention another common objection that I don’t find compelling at all: the moral hazard argument. If geoengineering works, that might destroy the incentive to reduce CO2 emissions. Well, yes, probably so. And who cares? The reason to reduce CO2 is that it has bad effects, not that they’re little sin molecules that it’s intrinsically immoral to release. A weaker version of this argument does have some merit; that is if geoengineering only works partially it may merely delay problems that could be actually prevented by emissions elimination. But that’s a reason for simply being very careful to make sure it works completely or almost completely, not a reason for abandoning the entire concept without study.
The methods themselves sound something like science fiction, not least of the reasons why is that at the moment that’s what they are. Among the methods proposed are orbital mirrors to redirect a tiny fraction of the sun’s light away from the earth, reflective sulfur particles in the upper atmosphere doing much the same thing, using iron to grow large blooms of plankton as a carbon sink, and a number of other clever and slightly alarming ideas.
I have no idea if any of this will turn out to work even in theory, much less whether it will be practical at cost scales below tens of trillions of dollars. If it does, it may well not be practical from a legal standpoint in that the tangle of environmental treaty obligations may not ever allow such a project to get off the ground.
But there’s no way to know without studying the problem in detail. I’m glad the NAS is at least looking into the problem. If it doesn’t pan out, it doesn’t pan out. But if it does, it might be very good news for this planet.