Five well-publicised geoengineering proposals to reduce the impact of climate change in the polar regions are “extremely unlikely” to work, and are a risk to the environment, say NZ and international experts in a new paper.
The researchers looked at ideas like injecting aerosol clouds into the atmosphere to block heat from the sun, or building underwater structures to protect ice shelves from warmer seawater.
The authors argue that further research into such techniques would not be an effective use of limited time and resources, and they also distract us from the critical priority of rapidly lowering our greenhouse gas emissions.
The Science Media Centre asked NZ co-authors of the study to comment. Feel free to use these comments in your reporting or follow up with the contact details provided.
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.
Conflicts of interest: Professor Naish is a co-author of this paper. “I don’t have any conflicts. My part of the research was funded by the NZ Antarctic Science Platform. I am currently Chair of the World Climate Research Programme.”
Our colleagues at the UK Science Media Centre gathered third-party expert comments. See below for a selection and read the full comments here.
Dr Shaun Fitzgerald FREng, Director of the Centre for Climate Repair, University of Cambridge, UK, 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.”
Conflict of interest statement: “I am involved in a number of projects on climate engineering funded by ARIA and NERC.”
Dr Bethan Davies, Chair in Glaciology, Newcastle University, UK, 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.”
Conflict of interest statement: “None to declare.”
Dr Leslie Mabon, Senior Lecturer in Environmental Systems, The Open University, UK, 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.”
Conflict of interest statement: “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.”
Prof Matthew Watson, Professor of Volcanoes and Climate, University of Bristol, UK, 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.”
Conflict of interest statement: “I am funded by ARIA to look at volcanoes as analogues for climate engineering.”