Five geoengineering approaches being considered for use in the Arctic and Antarctica are highly unlikely to help the polar regions, would harm ecosystems, face major geopolitical challenges, and most likely reduce our chances of reaching net zero by 2050.
This is according to a new assessment by an international research team, including the University of Southampton, which examined technological fixes intended to delay or mitigate the impacts of climate breakdown.
Published in Frontiers in Science , the assessment suggests these geoengineering proposals are likely to cost tens of billions while reducing the pressure on policymakers and carbon-intensive industries to reduce greenhouse gas emissions. They are also likely to introduce additional ecological, environmental, legal, and geopolitical problems.
"The polar regions are among the harshest environments on Earth, where even basic logistics are extremely difficult," says Dr Alessandro Silvano from the University of Southampton.
"Implementing geoengineering at this scale would demand an unprecedented human presence in the polar regions-something far beyond what has ever been attempted. Yet proposed ideas overlook these realities.
"Logistical hurdles, geopolitical tensions, environmental harms, and the sheer scale of such interventions are often underplayed in discussions. Turning these concepts into real-world action introduces a whole new level of complexity-a perspective largely missing from the current narrative."
Geoengineering is a divisive topic among experts. Some cite large uncertainties in effectiveness, risks of negative consequences, and major legal and regulatory challenges. Others argue that geoengineering could buy time while the world cuts emissions, and warn against dismissing proof-of-concept research.
To conduct the new assessment, an international research team looked at five geoengineering approaches that have received the most attention to date:
- stratospheric atmospheric injections (SAI) - releasing sun-blocking chemicals such as sulfur dioxide into the atmosphere to reduce the sun's warming effect
- sea curtains - preventing warm water from reaching and melting glaciers
- sea ice management - artificially thickening ice to slow melting or scattering glass microbeads on remaining sea ice to increase its reflection of solar radiation
- basal water removal - pumping ice melt away from underneath ice sheets to reduce ice loss
- ocean fertilisation - adding nutrients like iron to polar oceans to trigger blooms of phytoplankton-microscopic creatures that sequester carbon into the deep ocean when they die
The team measured each proposal against its likely effectiveness and feasibility, potential negative consequences, cost, existing governance frameworks, scale and timing, and the likelihood of appealing to those vested in avoiding emissions cuts.
According to the expert assessment:
- None of the ideas currently benefit from robust real-world testing. No field experiments exist for sea curtains in icy conditions. Ideas that had been tested were either unsuccessful or small-scale
- Deploying large-scale infrastructures, such as sea curtains, into the real world faces enormous, likely insurmountable logistical challenges
- All proposals would bring environmental challenges and damages
- Each proposal is estimated to cost tens of billions to set up and maintain. These costs are likely underestimates, and could be higher still when the cost of knock-on consequences is factored in
- No governance frameworks exist to regulate SAI or sea ice management. All proposals were found to require extensive political negotiation and the creation of new governance structures and infrastructure. The current geopolitical conditions represent a major challenge to any meaningful polar geoengineering deployment
- Most of the proposals cannot be deployed at a large enough scale, quickly enough, to effectively tackle the climate crisis within the limited time available
- All proposals risk appealing to those looking to avoid emissions cuts
Although the authors acknowledge the importance of explorative, proof-of-concept research, they say that continuing to pursue these five polar geoengineering proposals could shift focus from the urgent systemic change needed to cut greenhouse gas emissions. This, they argue, risks splitting monetary and research resources when time is of the essence.
"Mid-century is approaching, but our time, money, and expertise is split between evidence-backed net zero efforts and speculative geoengineering projects," said lead author Prof Martin Siegert from the University of Exeter.
"We're hopeful that we can eliminate emissions by 2050, as long as we combine our efforts towards reaching zero emissions. The good news is that we have existing goals that we know will work. Global heating will likely stabilise within 20 years of us reaching net zero. Temperatures would stop climbing, offering substantial benefits for the polar regions, the planet, and all lifeforms."
The paper Safeguarding the Polar Regions from Dangerous Geoengineering: A Critical Assessment of Current Concepts and Future Prospects is published in Frontiers in Science and is available online.
