The European Commission Receives Recommendations on SRM

On December 9, 2024, the European Commission – the executive arm of the European Union (EU) – received a formal Scientific Opinion on SRM from their group of chief scientific advisors. While in general the advisors urge a cautious approach toward SRM, they also recognise that SRM might provide valuable benefits if global temperatures overshoot target levels. The advisors put forward five policy recommendations to guide future European activities related to SRM, which are summarised below:

• Recommendation 1: Prioritise emissions cuts. Policies should aim to limit overshoot as much as possible.
• Recommendation 2: Adopt an EU-wide moratorium on deployment of SRM. This recommendation is based on the view that near-term deployment would violate both the precautionary and “do no harm” principles.
• Recommendation 3: Negotiate a global agreement on SRM that prohibits deployment in the foreseeable future but allows for outdoor research that “does not pose risks of local and transboundary environmental or social harms”. Negotiations should be informed by a comprehensive public consultation. This agreement should reiterate and strengthen the existing de facto (though in practice immaterial) ban on “hostile” use of SRM under the Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques (ENMOD). The agreement should also be supplemented with a monitoring system and prohibit the use of “cooling credits” derived from SRM.
• Recommendation 4: Promote responsible research on SRM, including with public funding, supported by a robust ethical framework – but not at the expense of research on mitigation and adaptation. Research conducted outdoors should be restricted to small-scale experiments and follow appropriate guidelines. A moratorium should be placed on large-scale outdoor experiments, defined as “associated with a risk of significant transboundary effects and harm beyond the place of intervention”.
• Recommendation 5: Conduct a periodic reassessment of SRM science every 5 to 10 years, possibly in connection with ongoing intergovernmental assessments. Such reassessment could provide the basis for revising these recommendations. In addition, citizen assemblies tasked with considering SRM should be initiated, and advanced tools for detecting and attributing the effects of SRM should be developed.

Taken together, these recommendations would pair strict limits on SRM deployment and large-scale outdoor experiments with expanded, publicly funded research on SRM, including small-scale outdoor experiments.

We reached out to three experts to share their views on these recommendations.

While I largely agree with the recommendations, my caveats regard their operationalization: the devil lies in the details as they say.

I strongly support prioritizing climate change mitigation and enhancing resilience and adaptation for better preparedness in view of the coming climate disruptions. The EU should indeed prevent SRM being used to offset emissions and the EU and member states must implement or even enhance their binding long-term mitigation targets.

SRM deployment must remain off the table for now, but responsible EU-led research on risks and uncertainties is vital: the lack of EU research funding to date jeopardizes its ability to shape international governance.

Preventing uncoordinated and ungoverned deployment starts with international cooperation on monitoring. In the absence of joint or networked monitoring efforts, any international decisions to not use SRM would not be credible. Furthermore, preventing uncoordinated SRM use that comes with significant risks of contributing to international tensions or even conflict will only be possible if there is robust international assessment of the devastating outcomes in case of such uncoordinated deployment.

Greater transparency in research, international assessments, and accessible information on its findings are key for any form of cooperative decision-making on use or non-use.

The benefits and risks of reflecting sunlight back into space to counteract global warming remain highly uncertain, with significant ethical concerns and socio-political governance challenges. The recommendations on SRM by the European Union’s science advisors mark a critical moment in global climate governance for this contentious technology. The advisors’ call for a moratorium on SRM deployment highlights growing recognition of its potential risks – such as regional weather disruptions, biodiversity impacts, and governance challenges, particularly unilateral actions that could disadvantage the Global South. On benefits, a moratorium underscores the urgent need for establishment of robust international frameworks to regulate SRM research and potential deployment.

While this precautionary approach may limit outdoor experimentation, it may align with calls for better understanding of the risks, benefits, and equity implications of SRM. From a developing world perspective however, emphasis on interpretation of the recommendations is expected to consider opportunities for inclusive research, transparent communication, and capacity building to ensure strengthened and equitable participation in shaping the SRM discourse. The recommendations should serve as a reminder to prioritize proven climate solutions but importantly recognize SRM’s continued presence as an option. Maintaining momentum in research and international dialogue on SRM is essential to ensure any decisions are evidence-based, inclusive, and aligned with global climate goals and interests.

The recommendations released by the Group of Chief Scientific Advisors to the European Commission would restrict SRM deployment and large-scale outdoor tests while promoting responsible SRM research. These recommendations are crucial for effectively regulating research and the possible use of these technologies. In particular, research and governance are currently highly skewed toward countries in the Global North. In addition, due to the vast knowledge gap, public trust is fragile, and misinformation is a growing threat in the Global South in the context of SRM.

The Intergovernmental Panel on Climate Change (IPCC)’s Sixth Assessment Report documented that SRM could offset some of the effects of increasing greenhouse gases without a quantitative evaluation. Although past research implies that temperature-related climate dangers like severe heat and extreme rainfall might be reduced nearly universally, understanding the regional hydrological response to SRM is still hazy.

It is essential to promote a scientific understanding of the physical impacts of SRM at the national level, along with knowledge of climate change and the impacts of various potential SRM responses locally. To ensure effective and fair SRM governance, climate-vulnerable communities in the Global South must lead and participate in research and decision-making processes, as they are most impacted by climate change and have the most at stake.

The views expressed by Perspective writers and contributors are their own and are not necessarily endorsed by SRM360. The goal of our Perspectives is to present ideas from diverse viewpoints, further supporting informed discussion of sunlight reflection methods.