Study Reveals Geoengineering Risks for Polar Regions

Recent research from the University of Exeter has raised significant concerns about the viability and safety of geoengineering projects aimed at combating climate change in polar regions. Led by geoscience professor Martin Siegert, the study, published in Frontiers in Science on September 9, 2023, assessed five prominent geoengineering methods and concluded that they could cause severe environmental harm with potentially catastrophic global repercussions.

The five geoengineering approaches under scrutiny include stratospheric aerosol injection (SAI), sea curtains, sea ice management, basal water removal, and ocean fertilization. While some proponents argue these methods could buy time in the fight against climate change, the researchers emphasize that they fail to meet essential criteria for responsible climate intervention.

Stratospheric Aerosol Injection and Its Challenges

Stratospheric aerosol injection involves deliberately releasing aerosols into the atmosphere to reflect sunlight and cool the Earth. Research currently focuses on four aerosol types: sulphur dioxide, titanium dioxide, and calcium carbonate. However, the study highlights that this method may create more problems than it solves. For instance, during polar winters, there is no sunlight to reflect, rendering the approach ineffective for half of the year.

Moreover, SAI poses the risk of termination shocks. If such a project were halted suddenly, global temperatures could surge within 10 to 20 years due to the greenhouse gases previously masked by the aerosols. Implementing SAI would require continuous operation for an extended period, yet there is no international framework to ensure funding or accountability if the project fails. The estimated cost for 30 countries to participate in such an initiative could reach $55 million annually.

Technical and Environmental Hurdles of Sea Curtains

Another proposed method, the construction of large underwater sea curtains, faces significant technical and environmental challenges. These structures aim to block warm ocean water from reaching polar ice sheets. However, installing such heavy foundations in the rugged seabed poses logistical difficulties. The Amundsen Sea in Western Antarctica, known for its harsh conditions, is only accessible for a few months each year, complicating operations.

The costs associated with sea curtains are staggering, with estimates suggesting over $1 billion per kilometre. Additionally, barriers in the water could disrupt marine life, creating further ecological ramifications. The selection of materials for these structures is critical, as they must not release toxic compounds into the water.

Concerns Over Sea Ice Management and Basal Water Removal

The study also criticizes sea ice management techniques, which involve scattering glass microbeads to increase ice reflectivity. The researchers point out that this method could require up to 360 million tonnes of microbeads annually, equivalent to the total global production of plastics. Concerns about the ecotoxicity of these beads and their potential to create a net warming effect on Arctic ice have been raised, suggesting that sea ice management may be economically unviable compared to direct emissions reduction strategies.

Basal water removal, intended to slow glacier movement by extracting subglacial water, is deemed flawed. This method is not only emissions-intensive but also requires ongoing monitoring and maintenance, further complicating the effort to mitigate glacier melt.

The Case Against Ocean Fertilization

Ocean fertilization, which involves adding nutrients like iron to stimulate phytoplankton growth, may sound promising but brings its own uncertainties. The researchers argue that controlling which species dominate in fertilized areas could disrupt local food chains. The scale of deployment needed for this method raises additional questions about its feasibility and effectiveness.

In conclusion, the study by Martin Siegert and his colleagues underscores the pressing need for “climate-resilient development” that prioritizes decarbonization and better management of protected areas. The researchers advocate for a shift in the relationship between humanity and the planet, emphasizing that tackling the root causes of climate change is essential for a sustainable future.

As global efforts continue to decarbonize, overcoming reliance on fossil fuels and transitioning to renewable energy sources will present significant challenges but remains the most promising avenue to avert catastrophic climate change.