By Olivia Colangelo

Solar Radiation Management (SRM), an idea introduced in the 1960s, aims to reduce Earth’s surface temperature by reflecting sunlight back into space. Contrary to popular belief, an SRM deployment would work to offset some of the impacts of climate change rather than reduce the amount of Carbon emissions and greenhouse gasses in the atmosphere.

SRM involves three primary techniques which would focus on the same objective: allowing more heat and infrared radiation to escape into space. The first method, marine cloud brightening, uses ocean salt crystals to increase the reflectivity of clouds. Similarly, cirrus cloud thinning involves the use of aerosol particles to thin clouds that lie higher up in the atmosphere.

Diagram of 3 potential implementations of Solar Radiation Management. (Photo courtesy of Carnegie Climate Governance Initiative).

The most viable technique involves releasing aerosols, such as sulfur dioxide particles, into the stratosphere to block sunlight. This process could be carried out via balloons or specialized planes that are capable of flying at high altitudes.

This idea was largely inspired by volcanoes, which release aerosol particles upon eruption. When Mount Pinatubo erupted in 1991, sulfur dioxide was expelled high into the atmosphere. This had the effect of temporarily cooling the planet by approximately 1 degree Fahrenheit (0.5 degrees Celsius).

Because attempts to curb CO2 have proven unsuccessful, scientists turn to SRM and solar geoengineering approaches as a last resort. Though cost-effective, SRM implementations pose skepticism among scientists and government officials. In the event of an oversight, solar engineering can deplete the ozone layer, which is responsible for shielding earth from ultraviolet radiation. SRM has the potential to exhaust the population’s crop supply, thus limiting food resources. Aside from this, Solar Radiation Management requires unreserved international collaboration, which is simply not viable in the world’s current political state.

Professor of global sustainability governance at Utrecht University, Frank Biermann provided his insight on the matter, “Governments should consider solar geoengineering in the same way they do chemical weapons, biological weapons, nuclear testing and Arctic mining.” In other words: proceed with caution.

The Biden-Harris Administration has taken SRM into serious consideration despite the risks and uncertainty associated with solar geoengineering. The White House recently published a report which encompasses SRM’s societal outcomes, ecological repercussions, and environmental impact. The plan also provides answers as to how implementations could be carried out in alignment with foreign affairs. Though SRM may have significant drawbacks, it is important to compare those risks with the current hazards associated with extreme global warming and the ongoing climate crisis.