Well-publicised polar geoengineering ideas will not help and could harm, warn experts

Five well-publicised polar geoengineering ideas are highly unlikely to help the polar regions and could harm ecosystems, communities, international relations, and our chances of reaching net zero by 2050.

image of arctic sea ice
Credit: NASA/Sinead Farrell

This is according to new research by an international team, including the University of Edinburgh, which looked at five of the most developed geoengineering proposals currently being considered for use in Antarctica and the Arctic.

The polar regions are home to fragile communities and ecosystems, as well as most of the world’s ice. Technological ‘geoengineering’ approaches have been proposed to delay or address the impacts of climate breakdown in these regions.

Published in Frontiers in Science this new review finds that these publicised polar geoengineering ideas are likely to cost billions in set-up and maintenance, while reducing pressure on policymakers and carbon-intensive industries to reduce greenhouse gas emissions. The proposals where also found likely to introduce additional ecological, environmental, legal, and political challenges.

These ideas are often well-intentioned, but they‘re flawed. As a community, climate scientists and engineers are doing all we can to reduce the harms of the climate crisis—but deploying any of these five polar projects is likely to work against the polar regions and planet.

Prof Martin Siegert (lead author) University of Exeter

The proposals

To conduct the new assessment, the researchers looked at five geoengineering proposals that have received the most attention to date:

  • stratospheric aerosol injections (SAI): releasing sunlight-reflecting particles such as sulfate aerosols into the atmosphere to reduce the sun’s warming effect
  • sea curtains/walls: flexible, buoyant structures anchored to the seabed to prevent warm water from reaching and melting ice shelves
  • sea ice management: pumping seawater onto sea ice to artificially thicken it, or scattering glass microbeads onto sea ice to boost its reflectivity
  • basal water removal: pumping subglacial water away from underneath glaciers to slow ice sheet flow and reduce ice loss
  • ocean fertilization: adding nutrients such as iron to polar oceans to stimulate blooms of phytoplankton—microscopic creatures that draw carbon into the deep ocean when they die.

They measured each proposal against their likely scope of implementation, effectiveness, feasibility, potential negative consequences, cost, and existing governance frameworks that would allow timely deployment at scale. They also assessed each proposal’s potential appeal to those vested in avoiding emissions cuts.

 

According to the review

Effectiveness and feasibility

None of the ideas were found to currently benefit from robust real-world testing. No field experiments were found to exist for sea curtains or sea ice reflection; SAI had only been tested with computer modelling, ocean fertilization experiments were inconclusive, and glacier water removal had not been demonstrated beyond limited drilling.

The authors note that the polar regions are some of the world’s harshest environments to work in, and even simple logistics are challenging to deploy. They assert that the scale of polar geoengineering would require a human presence in the polar regions unlike anything we have considered to date, and say that many of the ideas do not consider these challenges

Negative consequences

Each of the five ideas were found to risk intrinsic environmental damage, with sea ice management carrying particular ecological risks, such as glass beads darkening the ice, and water pumps requiring vast infrastructure. The authors also found that the risks of SAI include ozone depletion and global climate pattern change; sea curtains risk disrupting habitats, feeding grounds and the migration routes of marine animals including whales, seals and seabirds; glacier water removal risks contaminating subglacial environments with fuels; and ocean fertilization carries uncertainty as to which organisms will flourish or decline, as well as the potential for triggering shifts in natural ocean chemical cycling

Cost

The authors estimate that each proposal will cost at least $10 billion to set up and maintain. Among the most expensive are sea curtains, projected at $80 billion over 10 years for an 80 km structure. They caution that these costs are likely underestimates, because they are likely to climb higher once knock-on consequences, such as environmental and logistical impacts, are considered

Governance

The authors found no existing governance frameworks to regulate SAI or sea ice management. Sea curtains and glacier water removal would fall under Antarctic Treaty provisions, while ocean fertilization is treated as marine pollution and restricted under United Nations rules. They caution that each proposal would require extensive political negotiation and the creation of new governance structures and infrastructure

Scale and timing

The authors conclude that, even if the proposals offered some benefit, none can be deployed at sufficient scale, fast enough, to tackle the climate crisis within the limited time available

Vested interest appeasement 

The authors found that all proposals risk appealing to those seeking to avoid emissions cuts. They note that claims about sea ice management preserving Indigenous Peoples’ rights and environments are misleading, and stress that only rapid decarbonization can achieve this without the introducing additional risks.

Split resources

Geoengineering is a divisive topic among experts and affected communities. Some cite large uncertainties in effectiveness, risks of negative consequences, and major legal and regulatory challenges. Others warn against dismissing proof-of-concept research, and argue that geoengineering could buy time while the world cuts emissions.

Although the authors acknowledge the importance of explorative research, they say that continuing to pursue these five polar geoengineering proposals could shift focus and urgency from the deep systemic change needed to cut greenhouse gas emissions. Geoengineering, they argue, therefore risks splitting monetary and research resources when time is of the essence.

The key message is that proposed geoengineering ideas for the Arctic and Antarctica are dangerous, environmentally irresponsible, incredibly expensive, politically and ethically unpalatable, and unlikely to be effective as climate solutions. They are a dangerous distraction from what we really need to do to address the climate crisis, which is to reduce our greenhouse gas emissions urgently and dramatically. Reaching net zero emissions by mid-century is possible, realistic and requires all of our collective efforts, so the focus needs to be on that, rather than getting distracted by the false promises and vested interests of geoengineering.

Dr Sian Henley The University of Edinburgh
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