My Thinking Evolves on Climate Change and Geoengineering

An engineered phytoplankton bloom, designed to
lock carbon on the seafloor, seen from space.

When folks talk about climate change for a lay audience they typically omit a discussion of geoengineering (meaning trying to deliberately lower the earth's temperature using technology), I imagine because they don't want to complicate the issue and the implications are uncomfortable. For one thing many of the strategies miss many of the worst effects of climate change; seeding the atmosphere with reflective chemicals like sulfur dioxide to decrease warming, for example, does nothing to combat ocean acidification. For another geoengineering would have to be an ongoing process, especially if we continue to burn carbon—better to use this opportunity to move to a renewable-based economy and put fossil fuels behind us.

I also suspect that it seems like a bit of a cheat, a way for humanity to wriggle out of the dire consequences of its actions.

But I've had in the back of my mind the vague idea that we'd end up doing it on a massive scale anyway, because we'd hit some point where the effects of climate change would be so extreme that it would be worth trying as a last-ditch effort to avoid a cataclysm. A new paper on the economics of geoengineering has changed my thinking on this somewhat:

This paper begins with the realization that there are really two different externalities involved in the climate change problem, that they have near-opposite properties, that they interact, and that it seems difficult to say offhand which one is more threatening than the other. The first externality, described by the above quotes, comes in the usual familiar form of a public goods problem whose challenge is enormous because so much is at stake and it is so difficult to reach an international governing agreement that divides up the relatively expensive sacrifices that would be required by each nation to really make much of a dent in greenhouse gas (GHG) concentrations. The classic governance problem here is to limit the underprovision of a public good from free riding.

A second less-familiar externality shows up in the scary form of geoengineering the stratosphere with reflective particles to block incoming solar radiation. This geoengineering-type externality is so relatively cheap to enact that it might in principle effectively be undertaken unilaterally by one nation feeling itself under climate siege, to the detriment of other nations. The challenge with this second global externality also appears to be enormous, because here too so much is at stake and it also seems difficult to reach an international governing agreement. If the first externality founders on the "free rider" problem of underprovision, then the second externality founders on what might be called the "free driver" problem of overprovision. If the first externality is the "mother of all externalities," then the second externality might be called the "father of all externalities." These two powerful externalities appear to be almost polar opposites, between which the world is trapped.

The problem of climate change is at root a collective action problem. A small group of people gain fabulous wealth from pollution, and a much larger group—literally the remainder of humanity—unevenly shoulder the costs. What I hadn't fully grasped up until now is that geoengineering has a similar problem. Without international coordination, it's eminently possible to face equally dire consequences from a panicked geoengineering scheme whipped up by some nation in mortal peril (like the Maldives). As Ryan Avent says:

What seems increasingly important to understand, however, is that the need for international cooperation will be if anything more serious in a world that doesn't act to control emissions (or control emissions enough to prevent substantial warming)... 

Just as serious a concern, however, is that pressure for geoengineering solutions will grow as the effects of warming intensify. Large, northerly countries like Canada and Russia have an almost unchecked ability to adapt but smaller and more equatorial places will quickly run out of options. It is unrealistic to suppose that unilateral geoengineering schemes won't be an inevitable result.

Such schemes could pose huge risks. Successful, precisely deployed efforts might nonetheless have unpredictable and substantial side effects or unpleasant distributional costs. Without a forum to address such effects, geopolitical tensions could worsen in a hurry. Even more frightening, uncoordinated efforts could be too successful, flipping earth from a warming scenario to a dangerously cold one.

So really, there is no escape from the desperate need for international coordination, geoengineering escape hatch or no.