Fibre-based ‘curtains’ around the feet of ice shelves and drilling holes through the glacier bed were the two main technological tools discussed at recent science conferences to slow sea-level rise due to climate change.
These interventions seek to deter the human-induced breakdown of ice sheets to slowdown sea-level rise. The sixth assessment report (AR6) by the Intergovernmental Panel on Climate Change (IPCC) estimated that global sea level could rise between 0.43 m and 0.84 m by 2100 relative to 1986–2005.
During the two workshops at the University of Chicago (October 2–3, 2023) and Stanford University (December 9–10, 2023), scientists and engineers called for efforts to evaluate the risks and benefits of deploying these interventions.
They also assessed the state of knowledge, including the strengths and weaknesses, on whether engineering interventions in Antarctica and Greenland could help slow sea-level rise. The outcome of the discussions has been published in a white .
These technological interventions broadly fall under geoengineering, which is deliberate and large-scale intervention in the Earth’s climatic system to reduce global warming.
Geoengineering attracted criticism in the past. Previously, in 2021, more than 60 senior climate scientists and governance scholars from around the world launched a global initiative calling for an International Non-Use Agreement on Solar Geoengineering. They argued that such technologies cannot be fairly governed globally and come with risks, labelling it a “dangerous distraction” from urgent climate action.
Solar geoengineering involves approaches to cool the Earth by reflecting solar radiation back to space. A popular example of this technology is the spraying of aerosols in the stratosphere to block incoming sunlight.
The paper points out that there is limited scientific and economic understanding of glacial interventions, particularly regarding large-scale ice-sheet deterioration (most notably that caused by the marine ice-sheet instability) associated with ice streams and glaciers in Antarctica and Greenland.
“It will take 15-30 years for us to understand enough to recommend or rule out any of these interventions,” John Moore, professor with the Arctic Center at the University of Lapland and co-author of the paper, said in a statement.
The report is also clear that the first order of business is to stop emitting carbon into the atmosphere. “We can never say often enough that that is the first priority,” Moore noted, adding that funding this research is important to avoid panicked decisions in the future.
Potential interventions like using a fibre curtain to prevent the collapse of Antarctica’s Thwaites and Pine Island glaciers are being proposed to reduce exposure of ice shelves to warm ocean water circulating under them.
These curtains could be attached to the seabed in front of the ice shelves. Modelling studies quoted in the paper suggest that modest curtains could slow sea level rise from the melting of these glaciers by a factor of 10.
“From preliminary studies, the actual engineering required might be smaller than you might think,” Douglas MacAyeal, professor emeritus at the University of Chicago, said in a statement. “For example, the Thwaites Glacier in Antarctica might require as little as 50 miles of seabed nets and curtains to make a difference,” he added.
The other potential intervention involved drilling holes through the glacier bed to slow the flow of streams that carry meltwater off the ice sheet and into the sea.
These holes could drain water from below the ice before it affects the glacier. The other option is to artificially freeze the glacier bed.
The paper also outlines that the risks remain unclear. For instance, installing curtains could deflect warm water to nearby ice shelves, which could then potentially reduce their stability, while changing local ecology in uncertain ways.
It could also affect the people living around the area. The researchers noted that the voices of thousands of people living in and depending on the Arctic, including many Indigenous peoples, be included.
While the drilling approach might be less harmful to ecosystems, it might also not be very effective. It would require a lot of engineering under harsh conditions.
Apart from these tools, researchers also discussed other less-known proposed interventions, such as using windbreaks to interrupt blowing snow and increase mass deposition, using cables and anchors to delay the breakup of floating ice shelves, adding reflective materials to the ice surface to reduce ablation and the like.
Shambhu Kumar is a science communicator, making complex scientific topics accessible to all. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
