Solar Climate Intervention

The “moral hazard” of solar geoengineering that Daniel Bodansky and Andy Parker examine in “Research on Solar Climate Intervention Is the Cure for Moral Hazard” (Issues, Summer 2021) is an illustration of a general phenomenon: introducing a new, potentially low-cost opportunity for reducing the risk of a loss may weaken the incentive to take other actions that prevent that risk from occurring. Some climate policy stakeholders have opposed solar geoengineering (SG) research and deployment out of concern that SG would discourage and hence substitute for emission mitigation. This prospect of new strategies influencing the use of existing strategies to combat climate change raises two important policy and political economy questions.

First, how is SG different from other approaches that reduce the risks of a changing climate? Substitution among climate change risk-reduction strategies already characterizes climate policy in practice. Investing in solar panels reduces the emission-cutting returns of energy efficiency investments, and vice versa. R&D on battery storage may enable dispatching of intermittent solar power, and reduce the returns to R&D on carbon capture and storage technology.

One may argue that substitution within emission mitigation is fine, but different from SG substitution, since the former represents various ways of preventing climate change risk, instead of potentially ameliorating the risk under SG. The same logic, however, applies to climate adaptation and resilience efforts. The emerging acceptance of the need for adaptation is clear evidence of insufficient emission mitigation over the past three decades. The failure of the single-pronged emission mitigation strategy has strengthened the incentives of individuals, businesses, and governments to invest in climate-adaptation programs.

This prospect of new strategies influencing the use of existing strategies to combat climate change raises two important policy and political economy questions.

Second, how could policymakers craft and implement a portfolio approach to climate change risk reduction? For example, would SG substitute for or complement emission mitigation? The underlying logic of the SG moral hazard critique is that decisionmakers optimize their risk reduction strategies. The analysis that SG deployment reduces the social return for a unit of emission mitigation thereby causing decisionmakers to undertake less emission mitigation presumes that decisionmakers already pursue optimal emission mitigation. The myriad imperfections and inadequacies of mitigation policy to date undermines this assumption and should give us pause about the prospect of optimizing the deployment of SG (and adaptation) to displace some emission mitigation.

Pursuing SG research and enhancing its salience among policymakers, stakeholders, and the public may represent an “awful action alert”—considering actions to block some of the incoming sunlight may galvanize public attention and enhance support for mitigation and adaptation. As my colleague Richard Zeckhauser and I emphasize in our paper “Three Prongs for Prudent Climate Policy,” such an awful action alert may spur greater emission mitigation and increase support for using every tool for reducing climate change risks. As Bodansky and Parker note in their compelling case for SG research, there is already preliminary social science research consistent with this notion. Going forward, we need to better understand the political economy of a portfolio approach to climate change risks. This suggests that a SG research agenda should address the political, economic, sociological, and international relations dimensions of SG research and deployment, in addition to the engineering and scientific dimensions of solar geoengineering.

Professor of the Practice of Public Policy

Harvard Kennedy School

Daniel Bodansky and Andy Parker’s call for more research into solar geoengineering rests on a neat but false dichotomy. They imply that research must be either constrained or extended. In practice, what is needed is neither a ban nor a free-for-all, but appropriately regulated multilateral research.

The authors are concerned about fears of mitigation deterrence or “moral hazard,” using the latter term despite widespread criticism of its inappropriateness. They argue that such fears will motivate more opposition to research, of the sort recently mounted by an international coalition of Indigenous peoples and environmental groups when Harvard researchers prepared to conduct solar geoengineering experiments in northern Sweden without first engaging with the local Saami people, or indeed other Swedish and European stakeholders.

In defending this sort of careless research management, Bodansky and Parker do not help their own case. They also slip into a rather one-sided review of the existing literature on moral hazard and mitigation deterrence, foregrounding individual effects rather than political, systemic, and emergent ones. Though it is generally accepted that in rich Western populations, exposure to ideas of solar geoengineering tends to galvanize concern over climate change, there is a striking contrast between the German and American experiments the authors cite. The German researchers showed that their participants supported stronger mitigation measures, while the Americans merely revealed that some individuals expressed more concern about climate change when they were told about a possible response that would not mean restricting their emissions. In other words, one of the experiments that Bodansky and Parker cite as rejecting moral hazard actually illustrated it.

What is needed is neither a ban nor a free-for-all, but appropriately regulated multilateral research.

Moreover, as the authors themselves acknowledge, politicians and businesses face stronger incentives than individuals to grasp at excuses for delay in climate action. Their solution is often to ignore the problem or hope for the best, deflecting attention to the reasonable—but tangential—concern that more research is necessary to deter future decisionmakers, faced with serious climate impacts, from ill-informed efforts at geoengineering. Unfortunately, the record of solar geoengineering research in providing such practical guidance is poor, with most modeling-based studies presuming away a whole range of technical and political limitations and risks that would make the carefully designed and modulated interventions they consider impossible in practice.

More research of this sort risks reinforcing unrealistic expectations of the possibilities. The authors might retort that this is exactly why more experimental research should be undertaken. Sadly, while small-scale experiments might help us understand how particular chemicals will react in the stratosphere, they offer little scope to understand large-scale climate system responses, or to help accurately attribute climate effects to geoengineering interventions. As has been long recognized, the only experiments that could answer such questions would actually constitute global-scale long-term interventions.

But the central problem of Bodansky and Parker’s piece is not their limited and partial coverage of the literature, nor their “knowledge-gap” theory of research that overestimates the learning that could be achieved through more experimentation, but their presumption that the choice we face is binary. There is a middle way, in which research is conducted in ways that minimize the risks of mitigation deterrence through prior development of binding international governance standards and procedures, including requirements for appropriate advance public engagement. Advocates for geoengineering research need to stop attempting to dismiss the risks of mitigation deterrence, and accept the challenge to collectively design research processes that minimize those risks.

Research Fellow, Lancaster Environment Centre

Lancaster University, United Kingdom

Cite this Article

“Solar Climate Intervention.” Issues in Science and Technology 38, no. 1 (Fall 2021).

Vol. XXXVIII, No. 1, Fall 2021