A significant majority of climate scientists believe that humanity will attempt to dim the sun through large-scale interventions before the end of the century, driven by the world’s failure to significantly reduce greenhouse gas emissions, according to an exclusive survey conducted by New Scientist. This growing consideration of “solar geoengineering” or “solar radiation modification” (SRM) comes with serious concerns about unintended consequences and the possibility of unilateral action.
The Rising Appeal of Solar Geoengineering
The survey, which polled nearly 800 researchers who contributed to the Intergovernmental Panel on Climate Change (IPCC)’s most recent assessment report, found that two-thirds expect interventions to “tweak the atmosphere” before 2100. Many experts express worry that this shift could be driven by a “rogue actor”—a private entity, billionaire, or nation-state—without a coordinated global framework for decision-making and risk mitigation.
“The concept of solar geoengineering worries me greatly, but I can see it is becoming more attractive as the world fails to address the problem of reducing greenhouse gas emissions,” stated James Renwick of the Victoria University of Wellington.
Methods of Solar Geoengineering
These interventions would likely involve manipulating Earth’s albedo—the amount of sunlight the planet reflects back into space. Proposed techniques include:
- Stratospheric aerosol injection: Spraying particles into the upper atmosphere to reflect sunlight.
- Marine cloud brightening: Spraying salt particles into low-lying ocean clouds to enhance their reflectivity.
Shaun Fitzgerald at the University of Cambridge’s Centre for Climate Repair highlights the growing awareness that current efforts to address climate change have been insufficient. “What are our real options? We might not like them, but it’s a case of not liking those and not liking the current trajectory that we’re on.”
Triggering Drastic Action: A Divided Opinion
Experts remain divided on what level of warming would justify such interventions. Just over 20% believe consideration should begin if global temperatures surpass 2°C above pre-industrial levels – a scenario that is increasingly likely. Others favor waiting for more extreme warming, while the majority believe there is no warming threshold that justifies manipulating the atmosphere.
Risks and Concerns
While theoretically, solar geoengineering could cool temperatures and buy time to reduce emissions, nearly all respondents emphasized the significant risks:
- Reduced motivation to cut emissions: A major concern is that climate interventions might distract from the urgent need to reduce greenhouse gas emissions.
- Disruption to rainfall patterns: Such interventions could severely impact agriculture and food security in vital regions.
- “Termination shock”: The sudden catastrophic warming that could occur if interventions were abruptly stopped.
- Unknown consequences: Many respondents cited the risk of unforeseen, potentially disastrous outcomes.
- For example, research has shown that enhancing cloud-cooling properties over the Indian Ocean could reverse drought in north Africa, but cause one in East Africa.
The Need for International Governance
The survey revealed widespread agreement—81%—that a new international treaty or convention is necessary to govern decisions related to large-scale deployment. “This is a global technology. No one can opt out of a geoengineered world. By the same extension, no one can opt out of a warmed world where we’ve rejected geoengineering,” notes Andy Parker at the Degrees Initiative.
A Shift in Perception
The growing interest in solar geoengineering represents a significant shift. Hundreds of millions of dollars in funding are flowing into the field, and research is increasingly presented at scientific conferences. In the UK, ARIA distributed £57 million in grant funding for SRM research, including small-scale outdoor experiments.
Just over one third of respondents have become more supportive of SRM research (though not necessarily deployment), and 49% support small-scale outdoor experiments to better understand risks and benefits.
Controversies and Reputational Risks
However, the field remains controversial: 45% consider it a taboo area of research. Some 11% have actively avoided contributing to SRM research due to concerns about professional reputation, as it signals a failure of climate science’s original goal: persuading the world to reduce emissions.
Overall, the survey results underscore the complex and potentially dangerous path that climate intervention is taking. While the possibility of cooling the planet through manipulation of sunlight is gaining traction, the inherent risks and the need for global cooperation are undeniable.
Given that a majority of the experts surveyed see the use of solar radiation management in the coming century as likely, there is a critical need to collect robust real-world data on the feasibility and potential impacts of such earth cooling approaches. – Mark Symes, ARIA’s climate-cooling programme
