Manipulating the Earth’s natural systems to counter global warming has long been viewed as a last-ditch option by many in the climate fight.
But advocates for geoengineering have grown more outspoken in recent years about the need to at least research the controversial climate fix, which includes methods such as spraying aerosols directly into the atmosphere to reflect the sun’s rays.
Supporters say rapidly warming temperatures — and insufficient progress in reducing planet-warming emissions — has created new space to talk about geoengineering. And while many readily acknowledge the risks, they say there’s peril too in allowing climate change to continue at its current pace.
“There is a serious risk that we will not get it together to mitigate and adapt [to climate change] sufficiently,” said Jessica Seddon, director of Yale University’s Deitz Family Initiative on Environment and Global Affairs.
Seddon said critics’ fears about the misuse of geoengineering have historical precedent. But she added they also constitute “a failure of imagination” and “very lopsided pessimism about humans.”
“It’s just in some ways insane to me that we can’t look at it that way and have a little more faith that maybe we could get it together to behave differently than maybe we have in the past,” she said.
Seddon delivered the analysis earlier this month at a panel hosted by SilverLining, a Washington, D.C.-based nonprofit group that has advocated for more geoengineering research.
The SilverLining discussion itself was notable for a couple reasons. Not only was it held in tandem with the renowned American Geophysical Union conference, the world’s largest gathering of Earth scientists, but it also framed geoengineering in a different light — as a “climate intervention” with an ethical imperative for more research.
There is perhaps a need for a rebranding.
The last few years have seen several geoengineering experiments go awry — due largely to opposition from government officials and community advocates.
Those kinds of concerns are exactly why there must be a frank and open discussion about geoengineering, say advocates. It can lead to better guidelines around its use and research.
At the same time, some climate policy experts argue that too much moral pressure from advocates is a danger in and of itself. It could raise the risk of a research group or company — or even a national government — going rogue before proper rules are in place.
That danger increases the need for immediate global guidelines, with particular input from developing nations and the world’s most socially vulnerable communities — the places that stand to lose the most from both climate change and unintended geoengineering side effects.
“The pressure is going to increase on climate intervention before I think a lot of the policy frameworks are in place, and people are going to take action,” said Bruce Hewitson, the South Africa National Research Chair on Climate Change and director of the Climate System Analysis Group at the University of Cape Town, at a separate panel hosted by the American Geophysical Union earlier this month.
“I foresee increased polarization around that.”
A history of controversy
Solar geoengineering has been a touchy subject for decades.
The concept revolves around a gamut of hypothetical strategies humans could use to artificially cool the planet by manipulating the sun’s rays.
Two of the most widely discussed ideas involve spraying reflective aerosols directly into the atmosphere or using particles to enhance the growth of bright clouds, both of which would beam sunlight away from the planet and lower global temperatures.
Scientists have published numerous studies over the years examining the potential risks and benefits of geoengineering. Some suggest the strategies could have unintended side effects, like negative impacts on precipitation patterns or atmospheric ozone concentrations, while other studies suggest that the benefits may outweigh the risks.
Experts also have pointed to the potentially catastrophic consequences of starting a large-scale geoengineering initiative, temporarily cooling the planet and then abruptly abandoning the project. It’s a scenario that could lead to an outcome known as “termination shock,” in which global temperatures rapidly skyrocket up again, threatening life on Earth.
Still, most of these studies to date have relied on model simulations rather than real-world experiments. That’s because solar geoengineering has, for most of its decadeslong history, been a largely hypothetical concept.
In recent years, though, worsening climate impacts worldwide amid global struggles to meet the Paris targets have punted the issue into more concrete discussions.
Experts widely agree that the world is all but certain to overshoot the 1.5-degree temperature target, the Paris Agreement’s most ambitious goal.
And there’s growing uncertainty about the planet’s ability to meet even a less challenging 2-degree target — a recent United Nations report warned that the treaty’s current slate of global climate pledges puts the world on track for as much as 3.1 degrees Celsius of warming by the end of this century.
At the same time, extreme weather events like hurricanes, wildfires, floods, droughts and heat waves are intensifying worldwide, while glaciers melt and global sea levels rise.
The growing global urgency to curb the worst impacts of climate change has helped spur an increased interest in geoengineering research, with some groups attempting or beginning field experiments within the last few years — sometimes amid local public opposition.
“Despite decades of efforts, greenhouse gas emissions are still too high, and overshooting the 1.5 C global-warming goal becomes likelier every year,” said Jesse Reynolds, chief of staff at the Degrees Initiative, a nonprofit that works to increase representation from developing nations in global conversations around geoengineering, in an email to POLITICO’s E&E News.
“Everyone agrees that cutting emissions is the top priority, but in this context solar radiation management (SRM) is receiving more attention.”
Pushback from local communities
The growing attention to geoengineering has led to public outcry in some cases.
Harvard University officially ended a high-profile solar geoengineering experiment in March after suffering years of setbacks.
Known as the stratospheric-controlled perturbation experiment, or SCoPEx, the project focused on a geoengineering strategy that would spray reflective aerosols directly into the atmosphere.
Organizers planned to carry out one of its first field tests in the Arctic city of Kiruna, Sweden, in 2021, a small-scale experiment they said would carry no safety concerns for local communities. But opposition from environmental groups and Indigenous communities in the region eventually led to the project’s suspension.
And a cloud-brightening experiment led by the University of Washington, which began trials in Alameda, California, earlier this year, shut down in June after city council members voted to block the project.
Geoengineering startup Make Sunsets made an even more controversial splash in 2022 when it began releasing reflective aerosols into the atmosphere over Baja California, Mexico — an unauthorized experiment that Mexican officials eventually banned. The company has since quietly moved its operations back to the U.S. and now sells “cooling credits” to buyers seeking to offset their climate-warming emissions.
At the SilverLining panel held at AGU, speakers pushed for better communication with local communities about small-scale geoengineering experiments — projects they say are unlikely to cause harm and provide baseline scientific information about the potential impacts of larger-scale projects.
This information is crucial to help the world make informed decisions about whether or not to proceed with intentional geoengineering deployment in the coming years, they say.
“It’s a difficult problem of needing people to better understand what [solar radiation management strategies] are, what these approaches are, understand the urgency of the problem, the timeline problem, how quickly the climate is changing,” said Sarah Doherty, a University of Washington atmospheric scientist who led the failed Alameda experiment.
“And that these are the only approaches that have been identified that could rapidly reduce climate warming, and that the research is basic climate research,” Doherty added.
David Keith, founding director of the Climate Systems Engineering Initiative at the University of Chicago and former co-lead of the shuttered Harvard experiment, added that recent studies suggest the benefits of geoengineering are likely to outweigh any potential negative side effects — he recently co-authored a paper concluding as much.
“The issue is: What are the benefits of [solar radiation management]? And how are they distributed? And what are the costs or harms?” he said in an interview with E&E News. “Comparison suggests that the benefits are much larger than the risks, and the benefits go much more to poorer people in the world. That is just as true at 1.4 [degrees] as it is at 1.7 as it is at 2.3.”
‘Responsibility and accountability’
But many experts argue that local communities have every right to be concerned about the impacts of even small-scale experiments — and that research shouldn’t proceed without more stringent guidelines.
Multiple high-level reports in the last few years have suggested as much, recommending that more research is needed alongside more serious global conversations around rules for research and deployment, centering the concerns of developing nations and the world’s most climate-vulnerable communities.
These include reports from the U.S. National Academies of Sciences, Engineering and Medicine; the European Commission’s science advisers; and the American Geophysical Union, the world’s largest Earth science society.
Some experts say recent conversations on geoengineering ethics still aren’t taking these concerns seriously enough.
“African countries have registered strong objections to the solar geoengineering agenda,” said Prakash Kashwan, an expert on climate governance and environmental justice, in an email to E&E News.
Yet these concerns weren’t adequately recognized in the recent panel hosted by the American Geophysical Union, he said, with panelists instead opting “to make vacuous assertions about the need to involve Global South countries.”
He added that groups in Europe and the U.S. are increasingly using “narratives of urgency and moral obligations and justice” to promote solar geoengineering without deeply considering environmental justice concerns about its deployment.
“Social science research on power and inequality show that simply asserting a justice motive does not absolve us of the responsibility and accountability for climate interventions,” he said.
Shuchi Talati, founder of the nonprofit Alliance for Just Deliberation on Solar Geoengineering, also expressed concern that some groups may be pushing a moral imperative for geoengineering research or deployment too far — and that underscores the need for more immediate global agreements on more stringent global rules.
“There is a subset of civil society and governments that is responding very negatively to this framing,” she said. “Ultimately, I do think the stakes have changed in recent years. In that context, there is a deep need to move beyond the vague discussions on research governance to start implementing them.”
The stakes are even higher as the incoming Trump administration — whose positions on geoengineering remain unclear — prepares to take office, she added.
“Right now, as we see growing support for [solar geoengineering] research, there is also insufficient support for the governance needs to shape that work,” Talati wrote in an email to E&E News.
“And in the context of massive political volatility, like the incoming Trump administration, I’m deeply concerned that we cannot depend on federal entities to shape the field in a way that will serve the public good.”
