International Symposium on Climate Overshoot, CDR, and SRM: Impacts, Society, and Governance

Global temperatures are rising rapidly and are likely to exceed the Paris Agreement temperature goals sooner or later. This “climate overshoot” raises difficult questions: What kinds of physical and societal impacts can we expect? How should we respond? What roles might carbon dioxide removal (CDR) and solar radiation modification (SRM) play in managing overshoot risks?
At the same time, these options raise profound social, ethical, and governance challenges:
How should societies evaluate the risks and benefits?
Who has the right to decide if and how CDR and SRM are used?
What governance frameworks are needed at national and international levels?

This symposium brings together researchers working on climate science, CDR, SRM, and social science to explore these questions and discuss directions for addressing the climate overshoot.

– Masahiro (Masa) Sugiyama is a Professor at the Institute for Future Initiatives (IFI), the University of Tokyo. His expertise lies in long-term climate policy, with research focusing on climate and energy scenario analysis and the governance of climate engineering from a public engagement perspective. He is a Coordinating Lead Author for Working Group III of the IPCC Seventh Assessment Report. Prof. Sugiyama has also served on the Harvard SCoPEx Advisory Committee and is a member of GESAMP Working Group 41 on Ocean Interventions for Climate Change Mitigation. He holds a Ph.D. in climate science and a master’s degree in technology and policy from MIT.

– Daniele Visioni is an Assistant Professor of Earth and Atmospheric Sciences at Cornell University. His main area of research is global climate modeling and the behavior and impacts of stratospheric aerosols, related to explosive volcanic eruptions and to proposals to deliberately inject aerosols in the stratosphere to potentially ameliorate the impacts of climate change, about which he has published over 100 peer-reviewed publications. He’s the co-chair of the Geoengineering Model Intercomparison Project (GeoMIP), and the co-chair of the World Climate Research Programme Lighthouse Activity on Climate Intervention Research, through which he collaborates with research groups around the world to improve the assessments of various Climate Interventions. He is a Lead Author for the Seventh Assessment Report of the IPCC, and was a coauthor of the 2022 WMO Scientific Assessment of Ozone Depletion.

– Kaoru Tachiiri is a Senior Scientist and a Group Leader of Japan Agency for Marine-Earth Science and Technology (Earth System Model Development and Application Group, Research Center for Environmental Modeling and Application, Research Institute of Global Change). His research interests include climate-carbon cycle feedback (including Transient Climate Response to Cumulative Carbon Emissions, TCRE), and human-earth system interactions. He participated in IPCC 6th Assessment Report (AR6) WG1 as a Contributing Author of the TCRE part in Chapter 5, and is currently engaged in AR7 WG1 as a Coordinating Lead Author in Chapter 9.

– Jörg Schwinger is an expert in Earth system modelling interested in the interactions of biogeochemical cycles with the climate system. His current research focuses on the potential role of carbon dioxide removal (CDR) in climate mitigation scenarios, the interactions of CDR with biogeochemical cycles, and the reversibility of the Earth system under overshoots. He has (co-)authored numerous studies that investigate CDR options using Earth system models. More recently, he also became involved in projects that investigate interactions of CDR and solar radiation management (SRM). He is a member of the CMIP7 CDRMIP steering group, and he has been working with the Integrated Assessment modelling community to improve the IAM-ESM modelling chain for CDR methods. He is generally interested in linking his research with other disciplines to better understand societal consequences and options for mitigation of climate change.

– Shinichiro Asayama is a Senior Researcher in the Social Systems Division at the National Institute for Environmental Studies, Japan. An interdisciplinary environmental social scientist, his research examines the social, political, and ethical dimensions of energy and climate issues, with a focus on the science–policy interface of climate change. Drawing on interpretive and critical social science, he studies how discourses, framings, and narratives shape debates around carbon dioxide removal and solar geoengineering. His work has appeared in leading journals, including Nature Climate Change, Climatic Change, Climate Policy, and Energy Research & Social Science.

– Osamu Nishiura has been a researcher at the National Institute for Environmental Studies (NIES) since 2024, where he is working on developing Integrated Assessment Models (IAMs) and quantifying mitigation scenarios using them. He is exceptionally knowledgeable in Computable General Equilibrium (CGE) models and has experience developing a CGE model that represents CDR technologies.
Recently, he has been participating in the Scenario Model Intercomparison Project (ScenarioMIP) for the latest Coupled Model Intercomparison Project (CMIP 7), where he is analyzing the CDR strategies of scenarios and the impacts of introducing CDR.

– Shingo Watanabe is the deputy director of the Research Center for Environmental Modeling and Application (CEMA) at the Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), and Professor at the Advanced Institute for Marine Ecosystem Change (WPI-AIMEC), Tohoku University. His research focuses on high-resolution modeling of atmospheric waves and interactions between stratospheric aerosols, ozone, and the Earth’s environmental system. He has contributed to numerous climate research projects as a core developer of the MIROC Earth System Model (MIROC-ESM) series. He is a Steering Committee member of the Geoengineering Model Intercomparison Project (GeoMIP) and of Atmospheric Processes And their Role in Climate (APARC), a core project of the World Climate Research Programme (WCRP).

Secretariat of the International Symposium on Climate Overshoot, CDR, and SRM
Email: geomip-2026-group★g.ecc.u-tokyo.ac.jp (★→@)