Solar Radiation Modification (SRM) refers to a range of techniques which aim to limit global warming by reducing the amount of solar radiation reaching the Earth’s surface (reflecting sunlight or increasing how much heat escapes back into space). Examples of SRM include:
- Marine Cloud Brightening (MCB), which involves the injection of sea salt aerosols into persistent marine low clouds (to increase their reflectivity)
- Stratospheric Aerosol Injection (SAI), which involves releasing reflective particles into the upper atmosphere to increase the reflection of sunlight back into space.
- Cirrus Cloud Thinning (CCT), which seeks to reduce the amount of cirrus clouds by injecting ice-nucleating substances in the upper troposphere – ultimately resulting in planetary cooling.
Views on SRM research are diverse, and conversations can be contentious. Some are concerned that the research and development of SRM would distract from vital efforts to reduce emissions. Others view SRM as a potential opportunity to limit heating, avoid dangerous ecological tipping points, and protect humanity from the worst impacts of the climate crisis. Many remain undecided, but see a need to study risks, uncertainties and potential benefits.
The European Union has asked for support in examining the conditions for research on SRM. Over the next three years, the Co-CREATE project will examine the governance principles and guidelines for responsible Solar Radiation Modification research. This will ultimately support decision-making on whether or not, and under which circumstances, SRM research and experiments may be warranted from scientific and societal viewpoints.
With few exceptions, proposed governance regimes for SRM research have come from scientific experts speaking on behalf of wider society. Instead, the Co-CREATE project engages with diverse stakeholders and rightsholders, including marginalised and affected communities such as indigenous peoples in the Arctic and across the Global South. This collaborative approach will anchor project results in a diversity of voices, cultural contexts, and value systems, reflecting the grappling of society with this complex and contentious issue.