Plan to cool Earth by spraying sulfate particles into the atmosphere sparks controversy

With 2024 marking the first year global temperatures exceeded 1.5 degrees Celsius above 19th-century averages, scientists are reconsidering a plan to reflect sunlight back into space to cool the planet.

As global emissions continue to rise and carbon removal technologies struggle to scale, researchers are looking toward a technique known as Stratospheric Aerosol Injection (SAI). The method is inspired by the 1991 eruption of Mount Pinatubo, which released volcanic particles that cooled the Earth by approximately 0.5 degrees Celsius.

Climate models suggest that injecting roughly 12 million tons of sulfur dioxide (SO₂) into the stratosphere annually could offset 1 degree Celsius of warming.

Researchers are now proposing a phased research program, similar to medical clinical trials, to evaluate the safety and efficacy of the technology. The initial stage would release a minute amount of SO₂—too small to impact the climate—to verify the accuracy of current computer models.

Subsequent phases would increase the scale to study how the particles disperse in the atmosphere. The goal of the program is to provide transparent scientific evidence for policymakers, ensuring they can make informed decisions before a worsening climate crisis forces drastic action.

The debate over geoengineering interventions—specifically Stratospheric Aerosol Injection (SAI)—presents a fundamental policy crossroads: is it a vital survival mechanism or a planetary-scale gamble? Proponents argue that rigorous research does not equate to a green light for deployment. Rather, it serves as a strategic "scientific hedge," establishing the guardrails necessary to clarify risks and preempt reckless unilateral action in the future.

The primary friction point is not technical feasibility, but global governance. In the absence of a robust multilateral oversight framework, the prospect of "tuning" the Earth's thermostat remains a geopolitical minefield. A single nation acting unilaterally could trigger catastrophic unintended consequences, shifting precipitation patterns and inducing localized droughts or floods far beyond its own borders.

For Vietnam, a nation at the frontlines of climate fragility, the stakes are existential. While the threat of sea-level rise inundating the Mekong Delta makes any potential cooling solution attractive to Hanoi, the risks are equally profound. If geoengineering disrupts the seasonal monsoons and rainfall cycles that serve as the lifeblood of the country’s agricultural sector, the intervention could prove as damaging as the warming it seeks to mitigate. Consequently, the trajectory of global SAI research remains a matter of vital national interest for Vietnam, regardless of where the science is conducted.

While this issue does not directly disrupt Vietnamese-American business operations—from the vibrant hubs of Little Saigon to the nail salon industry and local phở restaurants—the community continues to monitor climate change developments with deep concern. Many families maintain close ties to relatives in Vietnam’s coastal regions and the Mekong Delta, where the existential threats of typhoons, flooding, and saltwater intrusion directly endanger the safety and livelihoods of their loved ones. These environmental challenges remain a significant point of interest for the diaspora, often weighing on the minds of those managing remittances or navigating visa processes such as F2B, H-1B, or EB-5 categories to support their families back home.