Geoengineering. Gernot Wagner

influence on national climate policies. The fossil-fuel lobby is one. Both carbon removal and solar geoengineering might be high up on the agenda if the goal is to delay CO₂ cuts as long as possible. That applies to fossil-fuel companies lobbying democratically elected leaders. It would apply even more so in so-called “petrostates,” where the national oil company is the government. Saudi Arabia comes to mind, with or without the public trading of Saudi Aramco shares. Oil is the source of the Saudi royal family’s power, and it clearly wants to maintain that status quo. The same goes for many other countries in the Middle East and well beyond.

Some of the more enlightened oil majors may have set themselves more or less ambitious decarbonization targets. All of them implicitly or explicitly emphasize “net” decarbonization – at the very least implying that direct air capture or other forms of carbon removal will very much be part of their corporate strategy. Moving only a small fraction of the vast marketing dollars traditionally spent on sowing confusion, or worse, on climate action to lobbying for either carbon removal or solar geoengineering ought to have quite a bit of (undue) influence on national policies.

      Then there is direct action by nonstate actors. Billionaires have typically topped that list. David Victor coined the term “Greenfinger” for a “self-appointed protector of the planet.”²¹ The screenplay writes itself. Greenfinger would have a rather conflicted identity. On the one hand, he would act in defiance of James Bond and his government. On the other, he might well see himself as acting on behalf of humanity, out of a desire to fill a void left by governments’ reluctance to deploy solar geoengineering.

The trouble with this picture of a billionaire savior? It’s not quite that easy. First, there is the raw math. Annual costs somewhere in the single-digit billions of dollars might be cheap for many governments. But even the average billionaire would deplete his or her wealth quite rapidly. Spending perhaps $5 billion consistently over many years might take a $100 billion fortune. That is a rather exclusive club. Bill Gates, among others, has shown interest in solar geoengineering, helping to fund David Keith’s work over the years and contributing $4 million of the first $10 million in funding for Harvard’s Solar Geoengineering Research Program, formally launched in 2018. This kind of research is indeed wise. It is also far from anything resembling full-scale deployment. Jeff Bezos made news in early 2020 with a $10-billion climate commitment. He would have to give in the order of that amount every year to sustain a deployment program.²² Although that may well be theoretically possible, it is far from likely.

      Much more importantly, any effort to move toward rapid deployment now would be too premature. Some governments might even consider private moves toward deployment by an act of terrorism and meet such attempts by force.²³ And there are lots of ways to outlaw or otherwise prevent private actors from deploying solar geoengineering against a government’s wishes. Billionaires tend not to give money to provoke. On the contrary, anyone wanting to push toward deployment despite formal policies and social norms would truly have to be committed to the cause and, even then, it may not be possible.

      All of this at least applies to centralized deployment of stratospheric aerosols, for example by newly designed high-flying planes. That might be the most cost-effective lofting technology known today, but it certainly is not the only one. Nobody knows for sure, as none of these methods has been tested, but anything from high-altitude balloons to rail guns might work. What these alternatives have in common is that, at least for balloons, they are less effective and costlier than planes. They are also highly decentralized methods of deployment. That might have rather high appeal to those seeking to go it alone – whether that involves rogue nations or nonstate actors.²⁴ Chapter 6 explores this scenario in detail.

For now, let me just say that the who of solar geoengineering is very much in contention. More importantly, the who may not be a single actor, or even a single type of actor. It may also not be a single solar geoengineering method. Cutting CO₂ is not monolithic. Carbon removal is not either. While solar geoengineering’s characteristics lend themselves best to one global, centrally coordinated method, the “rational” implementation policy, detailed in Chapter 4, is far from the only scenario, and it might be far from the most likely one.

      The geoengineering dilemma

      The prisoner’s dilemma is famous for boiling down the conundrum of why two perfectly rational individuals – rational, that is, other than having committed the crimes that put them in this situation in the first place – act selfishly and tell on each other, even though cooperating would be better for them as a whole.²⁵ Each player acts in their self-interest, given the circumstances. Both end up worse off as a result. It’s a simple manifestation of the free-rider phenomenon governing CO₂ emissions cuts.

      Game theory is stock full of many more such dilemmas. Many attempt to capture the world in simple 2×2 matrices involving payoffs for various actions, some more contrived than others. (Game theory, of course, is not alone. See “Trolley Problem.”)²⁶ Despite some very real limitations, these thought experiments are often useful and instructive, explaining much broader points without all the verbiage. Bear with me. We will use the same logic throughout the rest of this chapter to try to understand the broader climate-policy dynamics at work.

      The desire to cut CO₂ emissions, or the lack thereof, can be summarized in a simple 2×2 matrix, as shown in Table 1.1.

In the table, bold letters with subscripts represent the moves, letters without subscripts represent the outcomes. It would be a bold move to claim that this table represents all of climate policy, but it does boil down some of the most important logic to its bare essentials. H implies high mitigation, L low. The outcome is simple: Unless both players agree to want H, the outcome will be L.

       Table 1.1. Climate mitigation policy as a result of players’ preferred moves: A high-mitigation agreement (H) is only possible if both players choose H over low (L) mitigation.27

Moves by players 1 \ 2	H2	L2
H1	H	L
L1	L	L

      Technically, Table 1.1 represents a weakest-link negotiation game. It’s the simplest possible way to show why getting to H is so difficult: Why should one nation, state, or other jurisdiction do more than the rest, if the rest will just stick to doing L?²⁸ While the logic encapsulated in this very question demonstrates the collective-action problem at the core of climate policy, it also immediately shows some pathways to try to overcome this situation. Indeed, books have been written on just that subject. Scott Barrett’s Why Cooperate? is a good place to start.²⁹

      First, cutting CO₂ emissions may not be as costly as often assumed.³⁰ Solar photovoltaic costs alone, for example, have famously declined by around 90% in the past decade alone. That might, in fact, be the most important caveat to our game here, and a hopeful one at that. Much of the delay in climate action, after all, may not be because of the lack of international coordination but because of domestic political obstacles.³¹ There, too, of course, solar geoengineering might play a role, invoking a type of moral hazard, or its inverse (see Chapter 7), though that’s not the type of interaction modeled here.

Another important caveat is that it may indeed be in some countries’ self-interest to pursue more ambitious policies around cutting CO₂ in order to persuade others to do the