Geoengineering Sounds Like a Quick Climate Fix, but Without More Research and Guardrails, It’s a Costly Gamble − with Potentially Harmful Results

While theoretically capable of cooling the planet, solar radiation management could have drastic side effects by shifting patterns of global atmospheric circulation that can lead to more extreme weather events. It also does nothing to reduce harms of excess greenhouse gases, including ocean acidification. A 2022 study published in the scientific journal Nature predicted that stratospheric aerosol injection could alter global precipitation patterns and reduce agricultural productivity.

Cloud brightening, while effective in theory, also needs more research to make sure that efforts to expand lower-level reflective clouds that can help cool Earth’s surface do not also increase the prevalence of the high-altitude clouds that warm the planet.

Space mirrors placed between the Sun and Earth could theoretically block 2% of incoming solar radiation and stabilize global temperature. But the technology is at least 20 years away from implementation and would cost trillions of dollars. More importantly, the overall global impact of shading Earth’s surface is largely unknown. It will decrease regional ocean and air temperatures in ways that may affect changes in the jet stream, rainfall, snow cover, storm patterns and possibly even monsoons. Much more research is needed to clarify these uncertainties.

Removing Carbon Dioxide from the Air
Carbon dioxide removal technologies generally carry lower risks than manipulating solar energy.

Carbon capture and storage removes carbon dioxide from power plants and factories and stores it underground in deep geological reservoirs. This has proven potential, but it raises concerns that leaks might contaminate aquifers, harm public health and ultimately fail to keep carbon out of the atmosphere.

The technology is also expensive and depends on the proximity of suitable reservoirs for storage.

Direct air capture, designed to pull carbon out of the air, is still in its early stages but offers the advantage of being able to reduce existing levels of carbon dioxide in the atmosphere. This, too, is costly, at upward of $600 per metric ton of carbon dioxide captured today, but innovators are getting funding from the U.S. government.

There are also natural ways to remove carbon. Planting trees, for example, can remove carbon directly from the atmosphere, but this is not enough. If all the land available for reforestation were replanted, it would still not be enough to reverse current global warming trends.

Ocean fertilization is another geoengineering hack intended to boost carbon sequestration, but research is at an early stage. The technique provides nutrients such as iron to increase the growth of phytoplankton, which use dissolved carbon from the atmosphere to grow their shells and tissue. But it may also have unintended effects for the food chain that could harm ocean life.

The Legal Void
Beyond safety, another important question involves accountability.

There’s a good chance that geoengineering meant to help one region would harm others. That’s because ocean and weather systems are globally interconnected.

So, who gets to decide which projects can go ahead? Right now, that’s a legal void.

There is no regulatory framework that can determine who is liable if something goes wrong. Multinational alliances, individual states, corporations and even rich individuals can act independently without consulting anyone. In the event of harm that crosses national boundaries, there is currently no clear path for recourse.

Striking the Right Balance
None of this is to say that the world should dismiss geoengineering.

Carbon dioxide removal techniques, such as planting trees and increasing soil carbon sequestration – retaining more organic carbon in fertile soils – may provide additional benefits to ecosystem services by increasing species diversity and boosting agricultural productivity. These are all positive outcomes and should be part of a global climate response.

Some forms of stratospheric aerosol injection might avoid the destruction of ozone and have short life spans in the atmosphere. However, more rigorous research, transparent global governance and robust legal and ethical frameworks to manage risks and ensure equity are needed first.

I believe all the technologies must be complemented by deep and sustained efforts to reduce emissions and transform the energy system to avoid the global impacts of sea-level rise, soaring temperature, droughts, storms, floods, fires, famine, species extinction and increasing human conflict.

As Riley Duren, a systems engineer from NASA, said in an interview with the space agency: “Geoengineering is not a cure. At best, it’s a Band-Aid or tourniquet; at worst, it could be a self-inflicted wound.”

David Kitchen is Associate Professor of Geology, University of Richmond. This article is published courtesy of The Conversation.