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A study published in Frontiers in Science looks at different polar geoengineering techniques.
Prof Matthew Watson, Professor of Volcanoes and Climate, University of Bristol, said:
“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.”
Prof Tina van de Flierdt, Head of the Department of Earth Science and Engineering at Imperial College London, said:
“This new paper provides a thorough review of some of the proposed geoengineering methods for polar regions.
“As somebody who has conducted challenging fieldwork in the Antarctic, I want to emphasize that all suggested methods are either scientifically flawed, unproven, dangerous, or logistically unfeasible. Time and money spent towards ‘engineering our way out of the climate crises’ risks omitting environmental damage and deters from the much-needed focus on accelerating proven climate mitigation and decarbonisation.”
Dr Shaun Fitzgerald FREng, Director of the Centre for Climate Repair, University of Cambridge, said:
“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.”
Prof Andrew Shepherd, Director of the Centre for Polar Observation and Modelling, Northumbria University, said:
“Our community would be stronger and healthier if geoengineering wasn’t such a divisive issue. While it’s true that interventions could be used to permit continued burning of fossil fuels, there is deep concern for our natural environment and the habitat it provides, and being motivated to preserve this is not dishonourable. Conservation is widely practised and supported in other parts of our lives, and at some point we may have to save Earth’s ice for future generations so its important we know how to do that safely.”
Dr Bethan Davies, Chair in Glaciology, Newcastle University, said:
“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 Pete Irvine, Research Assistant Professor in Geophysical Sciences at the University of Chicago and Editorial Director of SRM360, said:
“We trust our doctors to objectively lay out the pros and cons of different courses of treatment so that we can make an informed choice. We should expect the same of climate researchers. However, here we see a one-sided analysis of polar geoengineering proposals that stresses only the side-effects, downsides and potential for misuse.
“The fact is that rising temperatures are the fundamental driver of most of the changes we’re seeing in the polar regions and stratospheric aerosol injection could halt global temperature rise in a matter of years at a relatively low cost. It is not an alternative to emissions cuts, it comes with side-effects, and it could prove very challenging to govern, but it seems like it might help to greatly reduce climate risks if used wisely.
“Solar geoengineering is not a substitute for emissions cuts and adaptation, just like medications are not a substitute for good diet and exercise, but these interventions might make a significant contribution to the health of our planet.”
Dr Phil Williamson, Honorary Associate Professor at University of East Anglia, said:
“Martin Siegert and co-authors identify serious scientific flaws and apparently unsurmountable governance problems relating to novel climate interventions in polar regions. These analyses are welcome, particularly their scrutiny of (almost-certainly unrealistic) proposals for manipulating sea-ice and ice-sheet flows – that have received insufficient objective attention to date.
Their paper also provides a clear rejection of actions they consider to be geoengineering more generally. Paradoxically, this weakens rather than strengthens their overall case, with its focus on protecting both the Arctic and Antarctic from climate change impacts. That rejection is partly based on the authors’ heroic optimism that existing emission reduction pledges will not only be greatly strengthened but also fully implemented ̶ unfortunately ignoring recent back-tracking in policy commitments, as well as evidence that the current governments of USA and Russia would actually rather like an ice-free Arctic, with its economic opportunities1 trumping any environmental concerns.
The authors’ usage of the term geoengineering is itself problematic. They acknowledge that all framings in this topic area can elicit value-judgement responses; nevertheless, the term ‘climate intervention’ would seem more neutral, with longstanding ambiguities relating to the meaning of geoengineering that have yet to be satisfactorily resolved (see Annexes I and II of 2012 CBD report2). Since Siegert and colleagues include ocean fertilization as a ‘proposed concept’ in their paper, they presumably regard this carbon dioxide removal (CDR) technique as geoengineering, consistent with most other definitions of the term. Yet they specifically state that their assessment does not include CDR technologies, whilst also accepting that CDR “will have to play a role in climate change mitigation”.”
2 https://www.cbd.int/doc/publications/cbd-ts-66-en.pdf
Prof Hugh Hunt, Deputy Director of the Centre for Climate Repair, University of Cambridge, said:
“Everyone is agreed that fossil-fuel burning is heating the planet with catastrophic consequences, also that halting global warming requires rapid and deep decarbonization. The paper argues that “net zero” by 2050 will be sufficient to meet the terms of the 2015 Paris Agreement. Unfortunately we have baked in exceedance of 2C (and we have crossed 1.5C) and even remarkable global efforts to reduce emissions will not prevent our crossing 3C by the end of the century.
“The paper argues that geoengineering concepts for polar regions are not feasible and that further research into these techniques would not be an effective use of limited time and resources, and that such research is a distraction from the priority to reduce greenhouse gas emissions. But there is no evidence for this. The only cited paper on “mitigation deterrence” dates from 2016 and it is not based on any data, but rather on a supposition that geoengineering is a distraction.
“Of greatest concern, however, is that the authors do not propose a strategy for avoiding warming beyond 2C and its catastrophic impacts – sea-level rise, droughts, floods, biodiversity loss. Research in geoengineering is essential and urgent, particularly in Arctic regions where the impacts are most apparent.”
Dr Leslie Mabon, Senior Lecturer in Environmental Systems, The Open University, said:
“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.”
‘Safeguarding the polar regions from dangerous geoengineering: a critical assessment of proposed concepts and future prospects’ by Martin Siegert et al. was published in Frontiers in Science at 10am UK time Tuesday 9 September 2025.
DOI: 10.3389/fsci.2025.1527393
Declared interests
Shaun Fitzgerald: “I am involved in a number of projects on climate engineering funded by ARIA and NERC.”
Phil Williamson: “No interests to declare, as a retired employee of Natural Environment Research Council/UKRI. I was lead author of the cited 2012 CBD report on geoengineering (and a follow-up in 2016); however, no payment was involved.”
Leslie Mabon “is an Ambassador for the National Centre for Resilience, a Scottish Government-supported network committed to ensuring Scotland’s response to emergencies and hazards is informed by the best available evidence. He is also an Associate Member of the Scottish Government’s First Minister’s Environmental Council, an expert panel which informs the First Minister on best practice and the latest science internationally for responding to the climate and biodiversity crises. He does not receive renumeration for either of these positions, and in both cases, the remit of the body is simply to ensure that policy and planning decisions are informed by the best available evidence. He is also commenting in an individual capacity, and his comments are not representative of any organisations.”
Hugh Hunt: “I am Deputy Director of the Centre for Climate Repair Cambridge and we are funded by various sources, most significantly the ARIA Exploring Climate Cooling programme https://www.aria.org.uk/opportunity-spaces/future-proofing-our-climate-and-weather/exploring-climate-cooling. I have no links with industry.”
Pete Irvine: “No interests to declare”
Andrew Shepherd: “None”
Bethan Davies: “None to declare”
Matthew Watson: “I am funded by ARIA to look at volcanoes as analogues for climate engineering.”
For all other experts, no reply to our request for DOIs was received.
This Roundup was accompanied by an SMC Briefing.