This is a radical and somewhat risky plan. But I think we should fully explore it. The best plan, Plan A, would be drastically and immediately decarbonize and

This is a radical and somewhat risky plan. But I think we should fully explore it. The best plan, Plan A, would be drastically and immediately decarbonize and cut CO2 emissions globally. However, we have ample evidence that that is not going to happen, or at least not fast enough. This is a tremendously difficult problem because it requires a supermajority of actors to agree on a course of action, despite some game-theoretic reasons not to. Without a dramatic geopolitical shift, it's simply not going to happen. Geoengineering is Plan B, strictly inferior to plan A. But it has the advantage that one sufficiently wealthy state or actor can do it unilaterally, meaning there is a non-zero chance of it actually happening. Right now I am pessimistic enough about Plan A that I expect Plan B may be necessary if we want to avoid the horrors of a +4.5c climate change. And I sincerely hope someone eventually has the balls to do it (after a massive amount of scientific due diligence to mitigate risks like termination shock.)