Proposed “geoengineering” projects designed to reduce the impacts of global warming in polar regions would be ineffective, extremely costly and environmentally dangerous, researchers have warned.
As Antarctica and the Arctic undergo significant change amid rising temperatures, some scientists and engineers have proposed novel technological “fixes”.
These have included giant floating walls to prevent warm water from reaching ice shelves, and the scattering of microbeads onto sea ice to increase its reflectivity.
Sea ice helps regulate earth’s temperature by reflecting the sun’s heat back into space, (Supplied: AAD/Tas van Ommen)
But a team of international researchers, including from Australia, has published a new assessment that finds such ideas could harm ecosystems, international relations and efforts to reduce emissions.
These are some of the radical options to engineer our way out of climate catastrophe
“These ideas are often well-intentioned, but they’re flawed,” lead author Professor Martin Siegert, from the University of Exeter, said.
“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.”
The assessment, published in Frontiers in Science, evaluated five geoengineering concepts that have received the most attention, including:
Stratospheric aerosol injections: the release of sunlight-reflecting particles into the atmosphere to reduce warmingSea curtains and walls: flexible, buoyant structures anchored to the seabed that prevent warm water from reaching ice shelvesSea ice management: artificially thickening ice by pumping seawater onto it, or scattering glass microbeads onto sea ice to increase reflectivityBasal water removal: pumping subglacial water away from underneath glaciers to slow ice sheet flow and reduce ice lossOcean fertilisation: adding nutrients such as iron to polar oceans to stimulate blooms of phytoplankton, which draw carbon into the deep ocean
The report found sea ice curtains would disrupt habitats, feeding grounds and migration routes of marine animals, including whales, seals and seabirds. (Reuters: Rob Suisted/social media)
The researchers examined the concepts against several criteria, including feasibility, effectiveness, consequence, cost and governance.
“According to our expert assessment, none of these geoengineering ideas pass scrutiny regarding their use in the coming decades,” the report stated.
“Instead, we find that the proposed concepts would be environmentally dangerous.”
The report found sea ice curtains would disrupt habitats, feeding grounds and migration routes of marine animals, including whales, seals and seabirds.
The report said the sea ice curtains could cost tens of billions of dollars each. (Supplied: Frontiers)
It warned that proposed sea ice management would require vast infrastructure in the remote polar regions, and microbeads would darken the ice.
It said basal water removal could risk contaminating subglacial environments with fuels, and ocean fertilisation could change the ocean’s natural chemical cycling.
Stratospheric aerosol injections would risk ozone depletion and changes to the global climate pattern, it said.
The report said aerosol injections would risk ozone depletion. (Supplied: Frontiers)
In relation to cost, the report found each proposal would cost at least US$10 billion to set up and maintain.
Among the most expensive concepts are sea curtains, which would cost an estimated US$80 billion over 10 years for an 80-kilometre structure, it said.
The report also warned that such proposals could be used to undermine global efforts to reduce greenhouse gas emissions.
“Geoengineering could be used by bad actors as a strategy to create the illusion of a climate solution without committing to decarbonisation,” it stated.
Co-author Dr Felicity McCormack, from Monash University, said it was vital that money is not wasted on trying to develop such projects.
Dr Felicity McCormack’s research focuses on predicting Antarctica’s future contribution to sea level rise. (X: @Monash_Science )
“Our time, money and expertise should be focused on reaching net zero emissions,” Dr McCormack said.
“Although research can help clarify the potential benefits and pitfalls of geoengineering, it is crucial that such research does not distract from the urgent priority of reducing emissions and investing in proven mitigation strategies.”
Scientists sound death knell for ‘doomed’ giant iceberg
Co-author Professor Steven Chown, also from Monash University, noted Antarctic Treaty nations recently found polar geoengineering projects “had no place in Antarctica or the waters surrounding it”.
“In considering these five geoengineering concepts, Antarctic policymakers, at their most recent meeting, have adopted a precautionary approach to geoengineering in the region, and largely agreed that none of the five concepts outlined meet essential criteria to be considered safe, responsible and feasible,” Professor Chown said.