The game theory of using geoengineering to fight climate change

The possibility of employing geoengineering could help break the political deadlock on a global climate change deal, according to a new paper.

Why it matters: Deliberately trying to engineer the climate to offset warming is risky and as yet untested. But with the effects of climate change compounding and further international agreements stalled, there may be no choice but to try — or at least threaten to do so.

As climate change worsens and climate politics remain polarized, the door opens for solar geoengineering, which would involve injecting aerosols into the atmosphere to reduce the amount of sunlight reaching the Earth and directly slow warming.

• Solar geoengineering would be much cheaper than drastically cutting carbon emissions, but it carries with it as yet unknown risks of side effects. That's why many environmentalists remain opposed to even experimenting with geoengineering.

Yes, but: A new paper in the journal Humanities & Social Sciences Communications suggests that the possibility of geoengineering could reframe the climate debate.

• Using game theory (more or less as described in this scene from "A Beautiful Mind"), Gernot Wagner and Adrien Fabre make the case that countries most vulnerable to climate change and most willing to engage in deep emissions cuts might prefer trying geoengineering, even with all its risks, rather than accept insufficient climate action.
• At the same time, those countries less worried about climate change might be more willing to compromise on deeper emission cuts if they fear that the other side would choose geoengineering over a weaker climate deal.
• The upshot is that just the existence of the option of geoengineering can nudge the two opposing sides into agreeing on tougher climate action.

Yes, but: Game theory aside, the worse climate change gets, the more likely one or more countries might try geoengineering to save themselves. That's why we'd be better off ramping up experiments on geoengineering now, so we know better what it can do — and what it shouldn't do.

• "We need to know whether or not this should be part of the climate portfolio," says Kelly Wanser, the executive director of SilverLining, a nonprofit focused on averting near-term climate risk.

Go deeper: Geoengineering might work best in small doses