Sign In
Australia; New Zealand; International; VIC
Media release
From:
Well-publicized polar geoengineering ideas will not help and could harm, warn experts
Five well-publicized 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.
This is according to a new assessment, published in Frontiers in Science, 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.
Yet this new review finds that five polar geoengineering proposals 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 were 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,” said lead author Prof Martin Siegert from University of Exeter.
"If we instead combine our limited resources towards treating the cause instead of the symptoms, we have a fair shot at reaching net zero and restoring our climate’s health,” said co-author Dr Heidi Sevestre from Arctic Monitoring and Assessment Programme Secretariat.
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.
"Mid-century is approaching, but our time, money, and expertise is split between evidence-backed net zero efforts and speculative geoengineering projects,” said Prof Siegert. “We're hopeful that we can eliminate emissions by 2050, as long as we combine our efforts towards reaching zero emissions."
"While research can help clarify the potential benefits and pitfalls of geoengineering, it’s crucial not to substitute immediate, evidence-based climate action for as-yet unproven methods. Crucially, these approaches should not distract from the urgent priority of reducing emissions and investing in proven mitigation strategies,” said Dr Sevestre.
They note that while their assessment focuses on the polar areas, other geoengineering ideas, such as marine cloud brightening and space-based solar reflectors, also need to be assessed against these criteria.
“The good news is that we have existing goals that we know will work. Global heating will likely stabilize within 20 years of us reaching net zero. Temperatures would stop climbing, offering substantial benefits for the polar regions, the planet, and all lifeforms,” said Prof Siegert.
Expert Reaction
These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.
Professor Tim Naish, Antarctic Research Centre, Victoria University of Wellington, and a co-author of this paper, comments:
“This paper puts a line in the sand by comprehensively showing that technological intervention, otherwise known as geoengineering, will not save the polar regions from catastrophic meltdown. The only realistic approach with a chance of keeping our planet below the 2°C safe guardrail set by the Paris Climate Agreement, and thus keeping our polar regions intact, is deep and rapid reductions of carbon emissions to net zero by 2050.
“This is why my co-authors and I reached the conclusion that we must focus our collective resources and intellectual horsepower on treating the root causes rather than the symptoms of climate change.
“Over the last 20 years our researchers in Aotearoa New Zealand, along with our international colleagues, have amassed a compelling body of evidence that shows a tipping point exists at 1.5-2°C global warming. When we cross this tipping point, one third of the Antarctic Ice Sheet will melt unstoppably, causing global sea-levels to rise unstoppably by 10-20 m. This will leave future generations with a big problem to deal with. Even on our current climate trajectory, the Intergovernmental Panel on Climate Change estimates one billion people will be impacted by coastal flooding due to sea-level rise by the end of the century.
“If we needed even more motivation, this latest assessment tells us to get on with the mahi and decarbonise now!”
Dr Shaun Fitzgerald FREng, Director of the Centre for Climate Repair, University of Cambridge, UK
“The paper correctly highlights the need for emissions reduction. And whilst we have been saying this for a long time, it is right to keep saying it.
“The authors say ‘some scientists and engineers claim that a mid-century decarbonization target will not be reached…’ This is true, but it isn’t just ‘some scientists and engineers’ who are concerned about the ramifications of this – it is in line with the findings of the IPCC. The IPCC says ‘global warming is expected to surpass 1.5°C above pre-industrial levels, even if pledges are supplemented with very challenging increases in the scale and ambition of mitigation after 2030 (high confidence)’.
“The key question is how we should respond to these concerns. The authors say ‘geoengineering in sensitive polar regions would cause severe environmental damage and comes with the possibility of grave unforeseen consequences’. Unfortunately, we are faced with severe environmental damage without geoengineering. So, rather than saying we should not look further into geoengineering, we should instead be seeking a debate about the relative risks of either trying to learn more about our options of geoengineering or preserving a paucity of knowledge and watching the environmental damage unfold before our eyes whilst we decarbonise the world.
“Both are possible pathways. But who should decide whether research into geoengineering is undertaken? There are many on the front line of the effects of climate change and who are least able to adapt, such as those from low lying islands in the Pacific where sea level rise from melting glaciers threatens to wipe out their countries, who deserve to be listened to. And many of them are eager to see if there are indeed ways of keeping the ice on Greenland and Antarctica whilst we get greenhouse gas levels down. This paper only covers one viewpoint whereas we need to ensure different perspectives and interests are also represented in a discussion.”
Dr Bethan Davies, Chair in Glaciology, Newcastle University, UK
“Geoengineering has received increased attention in recent years, as it sadly looks increasingly likely that it will be very difficult to meet the net zero goals by 2050, needed to keep global warming below the levels identified in the Paris agreement. Much of this geoengineering work has lacked adequate and thorough scrutiny from polar scientists and geopolitical experts, which as a community has been slow to respond to these. This therefore is a very welcome perspective paper that carefully explores the scope of implementation, effectiveness, feasibility, negative consequences, cost and governance. The paper is very clear that interventions such as stratospheric aerosol injection, sea curtains, sea ice management, basal water removal and ocean fertilisation lack evidence that they are effective in achieving their stated goals, are prohibitively costly, and would be challenging to install and govern given the geopolitical complexities of the Arctic and Antarctic. The geopolitical challenges that these interventions would pose is clearly laid out, as are the feasibility and effectiveness, negative environmental consequences and prohibitive costs. It is important that we don't look to polar geoengineering as some kind of easy solution to the climate crisis, and one that means that we can avoid the worst impacts of failing to meet the net zero goals agreed at the Paris COP. Fundamentally, the paper shows clearly and farsightedly that these polar geoengineering interventions are a dangerous distraction from reducing carbon emissions and do not pose a realistic or cost effective solution.
“The manuscript is thorough - it reviews well the existing shape of the literature. Til now, this has largely been fairly one sided, with most of the scholarly debate focused around those who support or conceptualise these interventions. The answering debate is long overdue. It highlights clearly how not only do these interventions pose highly significant political, cost and governance interventions, but there are also significant concerns about technological viability and effectiveness, i.e. whether they would actually work.
“The real world implications are well considered. Before geoengineering is considered a feasible action, the political, cost and feasibility implications all need significant further study. Effectiveness is well considered through reviewing the modelling and other studies that have been undertaken into these geoengineering interventions. “There is a difference between polar and non-polar geoengineering - this argument comes from leaders in the polar science community and so is focused in that area. The community would welcome more debate in this area from those in different fields.”
Dr Leslie Mabon, Senior Lecturer in Environmental Systems, The Open University, UK
“This study is a review paper, which means that rather than conducting new research themselves, the author team brought together a breadth of existing scientific evidence on different types of geoengineering and assessed the main similarities and contestations across the studies that have been done to date. The authors follow on from previous groups of scholars to express concern over geoengineering as a climate change response. For example, in 2022, over 60 global climate change scholars signed an open letter calling for an International Non-Use Agreement on Solar Geoengineering. In both cases, scientists' concerns have circled round the same areas: the risks are not well enough understood, the governance frameworks are not well developed, and society's time and money is better spent on reducing emissions and preventing harmful climate change through proven approaches such as renewable energy deployment and behaviour change.
“One of the most important real-world implications the authors draw out from this study is that for most of the technologies they review, the adequate governance frameworks are not in place. This matters because even if the technical and scientific case for geoengineering could be made, without the right governance arrangements to enable negotiations between countries, geoengineering technologies are unlikely to be able to be deployed in time to respond to the most urgent climate threats our society faces. It is also notable that the authors engage with some of the ethical and moral arguments around geoengineering. All of this serves as a reminder that, as the study authors note, geoengineering is a social and political issue as well as a technical and scientific one. It is therefore vital that scholars from the arts, humanities and social sciences are engaged in weighing up the evidence for and against contentious approaches such as geoengineering, alongside natural and physical scientists."
Prof Matthew Watson, Professor of Volcanoes and Climate, University of Bristol, UK
“Climate Engineering is a complex and important idea and anathema to many people who are concerned about climate change. This is understandable, given the scale of the challenge and the inherent risks in proposed engineering solutions to climate change. The authors do a good job of highlighting those risks, but do not specifically deal with those risks within the context of the risks from climate change itself. What they highlight is a series of concerns, felt by many, but in a very one sided way, and seem to have found only the research that supports their arguments. For example, it simply isn't correct to say SAI is only studied in models: Mt Pinatubo, 1991, demonstrated and quantifies the effects of sulfate aerosol cooling, and there is much still be learned from natural analogues.
“When approaching the conclusions of the paper I noted a summary section on feasibility, risks and costs. I first assumed that the authors had considered conventional mitigation as a counterweight, in the same way the authors had approached the climate engineering technologies. That would have been incredibly useful, but instead the paper reads like a group of concerned scientists presenting a perspective with an unreasonable amount of surety. The paper would have been better if it did not use the words safeguarding or dangerous in the title. Those regions are not safeguarded at the moment, far from it, and continued ice loss presents dangerous risks that were not considered here, noting that the authors are passionate about polar regions, and have spent their lives studying them.
“Whilst the cost of climate engineering is indeed likely to be somewhat higher than science budgets, it is much, much lower than conventional mitigation and/or adaptation. This, in my view, does not make climate engineering more attractive, but again might have been illuminated in the paper. The authors' central tenet, that mitigation will work, looks horribly unrealistic (I wish it weren't) given the recent proclamations around, for example, drilling the North Sea dry.
“It may be that climate engineering is not the route out of our current malaise. I hope so. We need to continue to have discussions, like the ones around this review, and, critically, we need to know more, before making such definitive prognoses.”
Multimedia
Attachments
Note: Not all attachments are visible to the general public. Research URLs will go live after the embargo ends.
