Solar radiation management (SRM)—that is, combating global warming by spraying particulates into the stratosphere to block sunlight heating the Earth[1]—is no longer the stuff of science fiction.[2] It is a matter of grave concern to the United States and the planet as a whole. 

This is why Congress last year instructed a group of federal agencies “to provide a five-year plan . . . with a scientific assessment of solar and other rapid climate interventions in the context of near-term climate risks and hazards.”  The White House Office of Science and Technology Policy is leading this effort, and in August asked for public comment on “research associated with climate intervention.” The urgency of this was underscored by the recent announcement that one company has started a pilot SRM project as a commercial venture, selling “cooling credits” based on the amount of warming averted by particulates it is launching into the stratosphere from Mexico.  

It is not surprising that policymakers have begun to think seriously about SRM; realistically speaking, we were going to exceed 20 C of global warming before the ink was dry on the 1992 Rio Treaty (a.k.a the United Nations Framework Convention on Climate Change), whose express purpose was to avoid that outcome. And while it’s promising that the administration is figuring out what research we need on SRM science, the flip side is the need to create a global SRM governance structure. Individual countries – or even individuals, since its relative cheapness has already spurred private efforts– unilaterally undertaking SRM is a frightening prospect.[3] 

Considerable effort has indeed been devoted to international SRM governance. But prospects for success will largely hinge on the United States’ participation which, unfortunately, will only happen with unprecedented effort. The fate of the 1982 United Nations Law of the Sea treaty is instructive: Bill Clinton signed and sent it to the Senate for ratification in 1996, where it has languished ever since. This is despite the fact that the Senate Foreign Relations Committee twice unanimously recommended ratification, as have the Pentagon, the Chamber of Commerce, the American Petroleum Institute, Sierra Club, Greenpeace, etc. 

The fate of that treaty—one with broad domestic and global support addressing an issue that has been the subject of international cooperation and governance for hundreds of years—does not bode well for the United States’ prospects of participating in a multilateral SRM pact. It will be far, far more difficult to ratify a treaty concerning technology that can affect the global climate and is orders of magnitude more complex, unfamiliar, and consequential. 

As such, it is critical that the United States immediately begin an intensive effort to familiarize Congress with SRM governance issues, starting with legislation that creates a comprehensive domestic governance regime covering SRM activities undertaken from within or affecting the United States.

Initial SRM governance legislation should focus on a permitting regime for experimentation undertaken from within the United States. This might require smaller-scale experimentation to inform a designated federal agency of the date, time, and location of the deployment, the type and volume of material to be used, the bona fides of the researchers, etc.[4] More importantly, federal permitting should be required once experimentation volumes increase above a certain threshold. (And, since federal permitting entails the environmental disclosure requirements of the National Environmental Policy Act (NEPA), rather than leave it to the usual process of initial agency rulemaking about what should be included in such an environmental impact statement, followed by litigation, followed by revised rulemaking, etc., Congress can simplify this by specifying the requirements for SRM NEPA analysis.)

This initial legislation should also criminalize unpermitted larger-scale SRM deployment by non-state actors that affects climate or weather in the United States. Individuals acting on their own accord is a serious threat, as low costs make SRM deployment by private citizens a real possibility, enabling them to inject sufficient aerosols to materially alter the planet’s temperature—and, equally frightening, severely destabilizing international relations.

Solar radiation management is an evolving policy response that requires a governance structure to avoid potentially catastrophic climate responses or international conflict. This issue is critical to our national security, and the 118th Congress should prioritize it, starting with the House Science, Space, and Technology Committee holding hearings on the vital need for an SRM domestic governance structure. Like it or not, attempts at SRM are coming, and we need to be prepared for them.  

[1]This particular form of SRM is known as “stratospheric aerosol injection”. There are other forms of SRM, such as “marine cloud brightening”, but their effects are far more localized.

[2]SRM has been the subject of some serious science fiction, e.g., Neal Stephenson’s Termination Shock(William Morrow, 2021); Kim Stanley Robinson’s The Ministry for the Future (Orbit, 2020).

 [3]$15 billion – affordable for one or more of the Elon Musks of the world – could materially lower temperatures for the entire globe. Stratospheric aerosol injection tactics and costs in the first 15 years; Environmental Research Letters, Vol. 13, No. 12.  

 [4]On paper, some skeletal reporting obligations have existed for decades. More than 50 years ago the 1971 Weather Modification Reporting Act, P.L. 92-205 mandated that anyone engaging “in any weather modification activity in the United States” submit such reports as required by the National Oceanic and Atmospheric Administration (NOAA), and criminalizing failure to comply with these requirements; in 1976, NOAA mandated reporting for a variety of activities, including “modifying the solar radiation exchange of the earth or clouds, through release of gases, dusts, liquids or aerosols into the atmosphere”. NOAA has recently recognized that its 1-page, check-the-box forms (last revised in 1981) are no longer adequate, and has sought public comment on how these should be updated. 

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