Joshua Horton
Harvard John A. Paulson School of Engineering and Applied Sciences
Key Points
• Scenarios of solar geoengineering deployment powerfully shape governance considerations and hence must be scrutinized.
• “Emergency” scenarios that envision rapid deployment are scientifically questionable and politically problematic for democratic countries.
• “Breakout” scenarios that imagine clandestine technology development are unrealistic.
• More conventional scenarios offer a more appropriate basis for thinking about possible future governance of solar geoengineering deployment.
When considering governance of solar geoengineering deployment, much depends on the specific deployment scenario that is envisioned. Scenarios are important because they establish the parameters of possible action, and contain assumptions about structures and behaviors. In this brief, I will comment on two deployment scenarios that often feature in discussions about solar geoengineering: “emergency” and “breakout.” In both cases, closer inspection reveals that key scenario elements are either unwarranted, undesirable, or unrealistic, rendering any deriva-tive analysis liable to lead to flawed, perhaps even dangerous, conclusions.
The emergency scenario imagines that accelerating climate change may result in a “climate emer-gency” necessitating rapid deployment of solar geoengineering to forestall catastrophe. In the literature, potential crises are frequently viewed in terms of climate tipping points, or thresholds beyond which abrupt, nonlinear effects take hold. Melting ice sheets and sea ice, and thawing permafrost are commonly offered as examples of climate tipping points. More recently, a group of scientists has advanced the “Hothouse Earth” hypothesis, according to which the cumulative effects of multiple positive feedbacks could push the Earth into a new, much less hospitable state (Steffen et al. 2018). Although the tipping point concept is entrenched in climate policy discourse, there is substantial disagreement within the scientific community about its theoreti-cal soundness and considerable skepticism regarding storylines based on crossing tipping points (IPCC 2013).
Whether emergency deployment is justified in terms of tipping points or in reference to some other event such as a weather-related disaster, declaring a “state of exception” to ordinary poli-tics in order to meet a (socially constructed) crisis risks a process of political degeneration in which rights are suspended, dissent is suppressed, power is concentrated, and decision-making is rushed and myopic. “Emergency” activities may have little or no connection to the precipitat-ing event, and may evolve from temporary measures to standprecipitat-ing policy. Framprecipitat-ing deployment
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of solar geoengineering as a response to a “climate emergency” entails both questionable science and perilous politics, and should be approached with caution (Horton 2015).
The second, breakout scenario envisions a solar geoengineering capability developed in secret and subsequently deployed. Small-scale research and development activities such as computer modeling, laboratory experiments, and even limited field tests might conceivably be conducted in secret, but the larger scale trials that scientists regard as necessary before full deployment would be unlikely to go undetected. Multiple high-altitude aircraft operating from numer-ous, geographically restricted airfields would be readily observable through a variety of means, including remote sensing. Large amounts of material – perhaps millions of tons – would need to be obtained and stored prior to dispersal. Billions of dollars would likely be required to pay for such testing. And hundreds to thousands of individuals would probably be involved in such an endeavor, all of whom would need to maintain strict confidentiality if their activities were to remain undisclosed. It is highly unlikely (though not impossible) that field trials of such magni-tude could be carried out covertly for any extended period of time, and hence unlikely (though again not impossible) that reliable, quickly deployable solar geoengineering technology could be developed in secret.
Other deployment scenarios common in the literature are equally unrealistic. Countries ponder-ing deployment as an act of desperation might possess resources sufficient to develop the tech-nology. But full deployment would require continuous stratospheric aerosol release for decades, at a minimum, and it is unlikely that such countries would be powerful enough to withstand the range of commercial, financial, diplomatic, and (in the extreme) military pressures that other states opposed to deployment could bring to bear to halt implementation. A “greenfin-ger” scenario (Victor 2008) in which a private actor sought to implement solar geoengineering would also likely fail: lacking even the rudimentary trappings of statehood, such as territorial sovereignty or a monopoly on the legitimate use of force, individuals or companies would likely face great difficulties mustering the infrastructural, political, and security capabilities necessary to carry out long-term deployment in the face of international opposition.
In contrast to emergency, breakout, and similar scenarios, more conventional scenarios such as
“temporary, moderate, and responsive” deployment offer a superior basis on which to pursue governance research (Keith and MacMartin 2015). Such scenarios should be grounded in a vision of international relations dominated by states operating in a context of complex interdepen-dence and responding to a multiplicity of positive and negative incentives. Far from overlooking the potential for rash actions, conflicting interests, and international tensions, this perspective anticipates such possibilities. Scenarios built on more typical understandings of world politics are more apt to generate useful insights about governance of solar geoengineering deployment than are storylines that rest on implausible assumptions or risky characterizations.
Unconventional scenarios, however, do point toward at least two avenues of constructive research. First, the enduring appeal of emergency framing, despite its weak empirical founda-tions and hazardous political implicafounda-tions, suggests that scholars should take seriously the possi-bility that actors may invoke a climate emergency as justification for deployment. The research
community should actively consider governance architectures designed to guard against this possibility. And second, solar geoengineering researchers should more fully appreciate the need for robust monitoring, not only during deployment, but prior to deployment. Strong monitor-ing capabilities are important for ensurmonitor-ing both that any implementation would be adaptive and flexible, and that any large-scale field experiments are successful and observable; visibility is essential to building trust.
References
Horton, J.B. 2015. “The Emergency Framing of Solar Geoengineering: Time for a Different Approach.” Anthropocene Review 2 (2): 147-151. https://doi.
org/10.1177/2053019615579922.
IPCC. 2013. Climate Change 2013: The Physical Science Basis. Cambridge, UK: Cambridge University Press. www.ipcc.ch/report/ar5/wg1.
Keith, D. and D.G. MacMartin. 2015. “A Temporary, Moderate, and Responsive Scenario for Solar Geoengineering.” Nature Climate Change 5. http://doi.org/10.1038/
NCLIMATE2493.
Steffen, W. et al. 2018. “Trajectories of the Earth System in the Anthropocene.” PNAS. www.
pnas.org/cgi/doi/10.1073/pnas.1810141115.
Victor, D.G. 2008. “On the Regulation of Geoengineering.” Oxford Review of Economic Policy 24 (2): 322-326. http://doi.org/10.1093/oxrep/grn018.