‘Solar radiation modification’ is an umbrella term for proposed technologies that would reflect more sunlight back into space, or allow more infrared radiation to escape into space, thereby creating a net cooling effect on the Earth’s climate. Such technological options include stratospheric aerosol interventions (the most studied option), marine cloud brightening, ground-based albedo modifications, ocean albedo change, and cirrus cloud thinning. Modelling studies have shown that these could potentially offset some climate change risks, including the increase in frequency and intensity of extremes of temperature and precipitation. However, they could also introduce a range of new risks related to the change of global weather patterns, including potential harm to the environment, climate and security; social, occupational, political and economic impacts; as well as ethical, moral, legal and justice issues.
While the EU strongly focuses on its objective to achieve climate neutrality by 2050 (Climate Law), the reduction of greenhouse gas emissions by 55% by 2030 (Fit for 55 legislative package), and adaptation to climate change (Adaptation Strategy), it can be expected that interest in some forms of solar radiation modification is likely to grow in the future, if we experience temperature overshoot due to insufficient mitigation or climate tipping points are reached.
Given the complexity of the issues related to solar radiation modification, the EU needs to carefully assess its position, considering all risks and potential opportunities also in view of engaging actively in discussions on international level to address related governance issues regarding its research, small tests, and potential deployment.
The Group of Chief Scientific Advisors to the European Commission has been asked to provide recommendations to support the EU position on solar radiation modification by answering the following questions:
- How can we address the risks and opportunities associated with research on solar radiation modification and with its potential deployment?
- What are the options for a governance system for research and potential deployment considering different solar radiation modification technologies and their scale?