Detection, monitoring, modelling, and attribution capabilities for Solar Radiation Modification (SRM) activities and assessing their impacts on Earth's climate and ecosystems

Expected Outcome:

Projects are to contribute to all of the following outcomes: European Union’s, Member States’ and Associated Countries’ policy making is supported with robust evidence and their visibility in deliberations of SRM strengthened. Evidence and new knowledge related to the points below supports the European Union’s, Member States and Associated Countries’ contributions to relevant international review and assessment processes of SRM, notably by the IPCC:

• Civil society, researchers, public authorities as well as policy and decision makers have access to a solid scientific-technological knowledge foundation concerning the detection, attribution and deterrence of SRM activities as a contribution to an emerging multilateral governance system spanning both SRM-related research and technological development.
• The development of a global SRM governance framework is supported through advanced knowledge, generated by desk research, modelling, earth observation, the documentation of development pathways of various SRM technologies and their potential impacts on the earth system and its parts (oceans, large-scale atmospheric circulation, regional climate such as monsoons as well as changes in precipitation), as well as on societies (impact on decarbonisation pathways, livelihood security, nature dependent value chains etc.) and ecosystems. These are considered substantial gaps by the Intergovernmental Panel on Climate Change (IPCC), Convention on Biological Diversity (CBD) and Group of Chief Scientific Advisors.
• Aerosol and cloud modelling capabilities for global and regional models concerning Stratospheric Aerosol Injection (SAI), Marine Cloud Brightening (MCB) and Cirrus Cloud Thinning (CCT)/Mixed Phase Cloud Thinning (MCT) and their effects on atmospheric chemistry and dynamics are enhanced as a solid scientific-technological base for a detection and deterrence system.
• Policy makers and public authorities have access to robust space-borne, ground-based, air-borne and in-situ EO data (e.g. Copernicus) based on any relevant physical, chemical or social, societal data for the purpose of detection, assessment and attribution for outdoor SRM-development activities. Knowledge about SRM-induced changes to be expected in ecosystems, like shifted precipitation patterns and altered light quality, associated marine and terrestrial net primary production, and on sensitive habitats is enhanced. The knowledge generated shall inform, in the context of SRM technology governance, the detection, monitoring and attribution policy, in the sense of an ecological alert system focused on protecting global biodiversity.

Scope:

Support provided under this topic must not be used to advocate, promote, or support the development of SRM. The conduct of SRM field experiments as well as the conduct of technical and operational SRM research is out of the scope. The activity aims at enhancing the capabilities to detect, monitor and attribute SRM-related research, innovation or deployment activities. The activity shall be conducted in line with the precautionary approach as outlined by the European Group on Ethics [1] , in accordance with the conclusion of SAPEA reports, the IPCC reviews, and build on the decisions of relevant international bodies, mainly CBD and support the ambitions of the Ocean Pact. In recent years, SRM has been the subject of increased debate amongst a variety of stakeholders. The debate encompasses multiple perspectives, including the scientific and technical challenges, inherent risks, governability and ethical considerations of proposed methodologies. SRM encompasses a range of strategies aimed at reducing global warming by reflecting the Sun's energy away from Earth or allowing excessive energy to leave the atmosphere through means other than reducing greenhouse gas concentrations. While the focus of relevant multilateral environmental agreements is fully on rapid greenhouse gas (GHG) emissions reduction and adaptation to climate change, SRM is being proposed by some actors as an additional measure to reduce warming and address negative impacts of climate change. In this framework, the Council conclusions on EU Energy and Climate diplomacy [1] of 21 April 2026 expressed concern that “ large scale climate interventions, in particular solar radiation modification, pose significant risks for the climate, the environment, security, and geopolitics” . Critical uncertainties regarding the effectiveness and wide-ranging impacts of SRM currently obstruct comprehensive risk analysis and evidence-based policy. Knowledge gaps coupled to a lack of robust, formal governance is particularly concerning, as the potential for unilateral deployment by state or private actors could trigger significant international tensions. Historically, SRM has been addressed within the framework of the CBD, specifically through Decision X/33 [1] adopted at COP10 and decision XI/20 adopted at COP11 [4] . Reaffirmed at CBD COP16, these decisions maintain what is widely recognized as a de-facto moratorium on the deployment of SRM and other geoengineering technologies to prevent irreversible ecological damage. The project under this topic should address critical knowledge gaps identified by the IPCC, CBD and Group of Chief Scientific Advisors related to the absence of an evidence-supported governance framework on SRM. The action shall enhance detection, monitoring, and attribution capabilities for SRM by leveraging EU leadership in Earth observation utilizing space-borne, ground-based, and in-situ data. This includes physico-chemical, and social, societal, media or any other relevant data. This robust monitoring framework should be designed to detect and attribute outdoor experiments and deter potential unilateral deployments by private or state actors. All deployment and field experiment-type activities are out of scope of this topic. In the absence of field trials different methods of physico-chemical measurements have to be validated against each other in a natural environment and modelling plays a crucial role for enhancing reliability, applicability and attribution capacity. To that end, the project is expected to significantly advance high-fidelity modelling of aerosol-cloud interactions, specifically targeting SAI, MCB, and CCT/MCT and develop a solid scientific basis for understanding how these methods affect atmospheric chemistry and dynamics. The project under this topic should contribute to the establishment of a potential future ecological early-warning system focused on protecting global biodiversity and expected to predict and monitor how SRM-induced changes, such as shifted precipitation patterns and altered light quality, might disrupt photosynthesis and associated marine net primary production, and sensitive habitats. By identifying these unintended consequences, the project aligns with the CBD and ensures that ecological protection remains a central pillar of any climate intervention research. SRM is mainly criticized for reasons including ethical concerns, general mistrust of technocratic interventions, lack of international governance and regulatory frameworks, risk of termination shock, as well as unknown long- and short-term side effects and high uncertainty. To achieve the goals of the project, the activity should therefore bridge the gap between technical disciplines and the humanities. Only through this transdisciplinary lens can the multifaceted threats to our ecosystems and societies be addressed. In December 2024 the European Commission’s Scientific Advisory Mechanism’s Group of Chief Scientific Advisors and European Group on Ethics have published expert advice on the limitations and requirements for research activities related to SRM technologies recommending inter alia highest possible transparency and open science practices. Further, the scientific advisory mechanism recommends setting limits to public support to SRM deployment technolog