We Need an International Agreement on Climate Intervention
"Storm at Dusk" by NASA's Marshall Space Flight Center is licensed under CC BY-NC 2.0
By Nicolás Esguerra
In Kim Stanley Robinson’s climate fiction book The Ministry for the Future, the Indian government unilaterally decides to cool the planet Earth after an extreme heat wave kills millions of people. Indian military planes fly into the stratosphere, spraying particles of sulfur dioxide that increase the atmosphere’s reflectivity. As a result, sunlight bound for Earth reflects back into space, temporarily lowering global temperatures.[1]
Though fictional, the book’s depiction of events is not so farfetched. Intervention in the global climate, often called geoengineering, would be relatively easy to accomplish. The type depicted in the book is called solar climate intervention.[2] The scientific processes behind it are generally well understood: they would mimic the cooling effect that the planet experiences after a large volcanic eruption, when ash particles deflect solar radiation.[3]
Solar climate intervention would not necessarily require new technologies. It would also be remarkably fast and cheap to deploy. Global temperatures could lower within a matter of weeks, and the National Academies of Sciences, Engineering, and Medicine estimate that the cost of cooling the Earth by 1°C—nearly the 1.1°C of human-induced warming since the late nineteenth century—would top out at $15 billion per year.[4] Given this price tag, many countries—and even a billionaire with a messiah complex—could unilaterally employ solar climate intervention on short notice.[5]
As climate change manifests and builds urgency to deploy climate intervention, the international community should create an agreement governing its research and potential use. In August 2021, the Intergovernmental Panel on Climate Change, a UN body that regularly assesses climate science, published a report declaring that the effects of global warming are already here.[6] Worsening storms, heatwaves, droughts, wildfires, and other disasters and atypical weather patterns have entered daily life around the globe. The report also emphasized that the window of opportunity for the Paris Agreement’s goal of “pursuing efforts to limit the [global] temperature increase to 1.5°C” is closing.[7] Even worse, increasing concentrations of greenhouse gases raise the risk of the climate reaching “tipping points” that accelerate warming.[8] Given this urgency, the drumbeat for climate intervention is only growing louder.[9]
Policymakers should act now to create an international agreement that governs the types of climate intervention that pose the greatest risk to the climate and have low technical barriers to implement. For example, scientists consider greenhouse gas removal to be relatively low risk, while solar climate intervention is fraught with “ethical, political, and environmental consequences,” according to the National Academies.[10] While the planet would be generally cooler, there would be localized adverse effects on human lives, natural resources, and ecosystems in vulnerable regions, belying solar climate intervention’s “cheapness.”[11] Changes in precipitation, for example, would likely cause harsh droughts or extreme rainfall in areas that would not have experienced them otherwise—disruptions to seasonal monsoons in South Asia or rainfall in arid North Africa being two such possibilities.[12] Solar climate interventions would also fail to address existing environmental problems (like ocean acidification, which some experts call the “forgotten crisis” of climate change) and create new issues (like ozone depletion at the poles).[13] Given the geographical distribution of these harms and benefits, countries should have a say in climate intervention governance that weighs the risks of climate intervention against the risks of continued warming. In the words of Yale University’s Martin Wolf, a postdoctoral fellow who recently completed his dissertation on climate science, we need an international agreement that “emphasizes global equity as much as a global average temperature.”[14] The agreement could be part of—or modeled on—the United Nations Framework Convention on Climate Change, which is structured to accommodate emerging science. Ideally, it would also involve the same countries and acknowledge that, combined with measures to reduce greenhouse gas emissions, the temporary use of climate intervention might help solve the climate crisis.
To get there, the international community should create a transparent governance structure that promotes research while putting up guardrails, such as limiting outdoor experiments and banning private projects. The agreement should facilitate scientific collaboration by creating global research goals, an independent scientific advisory body, and monitoring systems to determine effects on precipitation and temperature. Countries should also commit public funding to climate intervention research. As Harvard physicist David Keith wrote in an October 2021 New York Times op-ed, “geoengineering research budgets are minuscule, and much of the work is accomplished after hours by scientists acting outside their institutions’ priorities.”[15] Lack of funding should be easy to address. Research might confirm that climate intervention is a bad option, but that should encourage, not deter, our efforts to understand it.
Some argue for an outright international ban.[16] Climate intervention, the argument goes, poses too great a risk to the planet and creates a moral hazard by decreasing high-emitting countries’ willingness to cut emissions.[17] But such a measure would introduce its own risks. An outright ban and stringent limits on scientific study might fail to secure participation from China, Russia, the United States, and other countries that already support climate intervention research.[18] Failure to include these key countries could be dire. The first U.S. National Intelligence Estimate on climate change, released in October 2021, describes unilateral testing or use of climate intervention without an international agreement as “a growing risk” that can exacerbate geopolitical flashpoints over the next two decades.[19]
Spoiler alert: In Robinson’s book, climate intervention does not prove disastrous. With some ingenuity and luck, humanity solves the climate crisis and goes on to live in harmony with nature. The real world is unlikely to be so straightforward. But as we barrel toward a climate future yet unknown, every option should be on the table—and every country should have a seat.
About the Author
Nicolás (Nico) Esguerra is a master's student at the Yale Jackson Institute for Global Affairs. A former relief worker, he is studying international climate policy, with a focus on adaptation, resilience, and disasters.
Endnotes
1. Kim Stanley Robinson, The Ministry for the Future (New York: Orbit, 2020).
2. Many scientists use the precise but somewhat inartful term “albedo modification.” The more technocratic “solar radiation modification” is also popular. See Elliot Diringer and Kelly Wanser, “Toward international cooperation on solar climate intervention,” Center for Climate and Energy Solutions, July 13, 2020, https://www.c2es.org/2020/07/toward-international-cooperation-on-solar-climate-intervention/; “Climate Intervention: Reflecting Sunlight to Cool Earth,” National Research Council, 2015, https://doi.org/10.17226/18988; “Introduction to Solar Radiation Modification,” Carnegie Climate Governance Initiative, https://www.c2g2.net/introduction-to-solar-radiation-modification/.
3. This type of solar engineering is more specifically referred to as “stratospheric aerosol injection.” See “Introduction to Solar Radiation Modification,” Carnegie Climate Governance Initiative.
4. “Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance,” National Academies of Sciences, Engineering, and Medicine, 2021, https://doi.org/10.17226/25762; The Intergovernmental Panel on Climate Change estimates that “global surface temperature was 1.09 [0.95 to 1.20]°C higher in 2011–2020 than 1850–1900.” See “Summary for Policymakers,” in Climate Change 2021: The Physical Science Basis, Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, ed. Valérie Masson-Delmotte et al. (Cambridge University Press, 2021).
5. Mark Harris, “Billionaire Geoengineering,” New Scientist 247, no. 3298, September 5, 2020, pp. 18–19, https://doi.org/10.1016/S0262-4079(20)31528-1; Kelsey Piper, “The Climate Renegade,” Vox, May 24, 2019, https://www.vox.com/the-highlight/2019/5/24/18273198/climate-change-russ-george-unilateral-geoengineering; Florian Rabitz, “Going Rogue? Scenarios for Unilateral Geoengineering,” Futures 84, November 1, 2016, pp. 98–107, https://doi.org/10.1016/j.futures.2016.11.001.; Daniel Bodansky, “The Who, What, and Wherefore of Geoengineering Governance,” Climatic Change 121, September 9, 2012, pp. 539–551, http://dx.doi.org/10.2139/ssrn.2168850.
6. “Summary for Policymakers,” Climate Change 2021: The Physical Science Basis.
7. The Paris Agreement’s temperature goal is to “[hold] the increase in the global average temperature to well below 2°C above pre-industrial levels and [pursue] efforts to limit the temperature increase to 1.5°C above pre-industrial levels.” Article 2.1(a), Paris Agreement to the United Nations Framework Convention on Climate Change, Dec. 12, 2015, T.I.A.S. No. 16-1104.
8. “Summary for Policymakers,” Climate Change 2021: The Physical Science Basis.
9. Tien Nguyen, “Will the World Ever Be Ready for Solar Geoengineering?,” Chemical & Engineering News, March 16, 2018, https://cen.acs.org/environment/climate-change/world-ever-ready-solar-geoengineering/96/i13.
10. “What Is Solar Geoengineering?” Union of Concerned Scientists, October 29, 2020, https://www.ucsusa.org/resources/what-solar-geoengineering; “Climate Intervention: Reflecting Sunlight to Cool Earth,” National Research Council.
11. For example, ocean iron fertilization can potentially deplete oxygen levels in nearby waters, creating “dead zones.” See Jeff Tollefson, “UN Decision Puts Brakes on Ocean Fertilization,” Nature 453, no. 7196, June 1, 2008, pp. 704–704, https://doi.org/10.1038/453704b.
12. “Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance,” National Academies of Sciences, Engineering, and Medicine.
13. “What Is Solar Geoengineering?”; Marlene Moses, “Ocean Acidification Is Global Warming’s Forgotten Crisis,” Climate Home News, May 15, 2017, https://www.climatechangenews.com/2017/05/15/ocean-acidification-global-warmings-forgotten-crisis/.
14. Martin Wolf (Postdoctoral Associate, Yale School of the Environment, Yale University), in discussion with the author, October 2021.
15. David Keith, “What’s the Least Bad Way to Cool the Planet?,” opinion, New York Times, October 1, 2021, https://www.nytimes.com/2021/10/01/opinion/climate-change-geoengineering.html.
16. “The UN Must Take on Geoengineering Governance,” Geoengineering Monitor, March 11, 2019, https://www.geoengineeringmonitor.org/2019/03/the-un-must-take-on-geoengineering-governance/.
17. Nguyen, “Will the World Ever Be Ready for Solar Geoengineering?”; Albert Lin, “Does Geoengineering Present a Moral Hazard?,” Ecology Law Quarterly 40, no. 3, 2013, https://escholarship.org/uc/item/7th0d0pd.
18. “National Intelligence Estimate: Climate Change and International Responses Increasing Challenges to US National Security Through 2040,” Office of the Director of National Intelligence, October 21, 2021, https://www.dni.gov/files/ODNI/documents/assessments/NIE_Climate_Change_and_National_Security.pdf.
19. “National Intelligence Estimate,” Office of the Director of National Intelligence.