Solar Radiation Modification: Approaches, Risks, and Ongoing Research to Cool the Planet

Understanding Solar Radiation Modification (SRM) Technologies

According to НВ — Техно: As global temperatures continue to rise, solar radiation modification (SRM) methods are gaining attention as potential tools to lower Earth’s temperature by reflecting sunlight away from the surface. These techniques involve dispersing reflective particles into the atmosphere or enhancing the brightness of ocean clouds to reduce solar absorption. Cutting-edge research is being driven by organizations like the UK’s Advanced Research and Invention Agency (ARIA) and the US National Oceanic and Atmospheric Administration (NOAA).

A significant natural experiment occurred 35 years ago in June 1991, when the eruption of the Pinatubo volcano in the Philippines injected approximately 20 million tons of sulfur dioxide into the stratosphere. This event temporarily cooled the planet by about 0.5 °C for nearly two years, demonstrating SRM’s climate impact potential. However, as climate expert Ekaterina Zaharieva notes,

“these technologies show promise but remain far from mature.”

Current Research and Field Trials

ARIA has allocated £56.8 million to fund 22 SRM research projects, including five involving field experiments. Among these initiatives are:

• Thickening Arctic sea ice by pumping seawater onto its surface in Canada during 2024−2025, potentially increasing ice thickness by up to 32 cm.
• Further fieldwork planned for two sites in Nunavut in 2026.
• Winter 2027−2028 tests focused on electrically charging fog droplets to study changes in their reflectivity.

On the international stage, the European Parliament issued a briefing on May 28, 2026, advocating a moratorium on deploying SRM within the EU. Similarly, the UN Convention on Biological Diversity has imposed restrictions on certain SRM field experiments. Efforts to reach a global consensus through UN Environment Assembly discussions have yet to succeed, highlighting the complexity of the issue. Climate scientist Keith Shine commented,

“There may come a time when the risks of SRM are considered less severe than the risks of insufficient climate action.”

According to the European Parliamentary Research Service (EPRS), developing specialized aircraft and delivery systems for SRM could take roughly a decade. NOAA launched a long-term program in 2020 called Earth’s Radiation Budget to study SRM, and in 2025, NOAA researchers simulated combining stratospheric aerosols with enhanced marine cloud brightness, increasing reflectivity by about 10%. Despite these advances, current projections estimate a 2.8 °C rise in global temperatures above pre-industrial levels, raising serious concerns. Keith Shine warns,

“Without significant changes in emission reduction strategies, we are on track to exceed the Paris Agreement’s 1.5 °C target soon.”

Meanwhile, ship emissions have historically brightened ocean clouds, offsetting 3−5% of warming caused by greenhouse gases. However, as shipping transitions to cleaner fuels, this cooling effect is diminishing.

While SRM technologies hold potential for mitigating global warming, they remain under intensive investigation and international debate. Given the accelerating pace of climate change and the slow progress in cutting greenhouse gas emissions, SRM might offer an alternative response. However, ethical, environmental, and geopolitical challenges must be addressed through global cooperation and regulatory frameworks.

Ongoing research and vigilant monitoring of SRM’s impacts are essential to safeguard ecosystems and avoid unintended planetary consequences, ensuring any future deployment is responsible and sustainable.

As we explore innovative solutions to combat climate change, it's important to consider the broader environmental impacts of human activity. For instance, recent findings reveal that over 260,000 metric tons of microplastics entered our oceans through rivers in 2022, highlighting another pressing issue that requires urgent attention. Understanding the implications of these pollutants can provide valuable insights into the effectiveness of initiatives like solar radiation modification. To learn more about this critical environmental challenge, see the full report on microplastics in our oceans.