The World Climate Research Programme (WCRP) has launched a Lighthouse Activity (LHA) on Climate Intervention Research. As current emissions reduction commitments are not sufficient to meet the Paris Agreements’ temperature goals, and global mean warming is likely to exceed 1.5°C above the pre-industrial level in the 2030s, overshoot narratives and climate interventions are increasingly being brought up as options to complement emissions reduction efforts and reduce or reverse warming. Climate interventions (CI) refer to deliberate large-scale manipulations of the planetary environment with the aim to counteract anthropogenic climate change. Following this definition, CI includes large-scale Carbon Dioxide Removal (CDR; also known as Greenhouse Gas Removal, or Negative Emissions Technologies) and Solar Radiation Modification (SRM; also known as Solar Reflection Modification, Albedo Modification, or Radiative Forcing Management).

CDR describes human activities that aim to intervene in the Earth’s carbon cycle by removing atmospheric carbon dioxide (CO2), through the enhancement of existing, or creation of new carbon sinks relying on biological, geochemical, or chemical removal processes, or a combination thereof.
Recent scientific assessments based on future scenario designs indicate that holding anthropogenic warming at Paris Agreement compatible levels is implausible without the implementation of CDR at scale. Furthermore, ambitious mitigation scenarios project the world to require net-negative CO2 emissions by mid-century to compensate for a carbon budget overshoot. Such a deliberate reduction in atmospheric CO2, through global net-negative CO2 emissions warrants the consideration of CDR implementations as a climate intervention activity.
However, there are significant uncertainties concerning the efficacy and side-effects of CDR implementation at scale, the additionality of multiple CDR implementations and the Earth system’s response to net-negative emissions.

SRM approaches aim to directly impact the Earth’s net radiation balance by either reflecting a percentage of incoming solar radiation back to space or reducing the amount of infrared radiation retained by Earth.
SRM is increasingly proposed as a complement to long-term emissions reductions and adaptation since it is not intended to reduce greenhouse gas (GHG) emissions and does not address the causes of anthropogenic climate change. Therefore, other environmental harms from increased concentrations of CO2 and other GHGs (e.g., ocean acidification) would continue even with SRM implementation.
While SRM might rapidly reduce global warming, the extent to which SRM could reduce climate change impacts, risks, or hazards has not been robustly established in the scientific literature, nor has the extent to which SRM might introduce new risks to people and ecosystems at both global and regional scales.

In addition to environmental risks, there are substantial technical, societal, political, ethical, and economic challenges associated with the implementation of proposed CDR and SRM approaches at the scale needed to slow or halt global warming.

The WCRP LHA on climate intervention research will explore potential future scenarios that include CI implementations and provide an objective overview of expected Earth system risks and opportunities, remaining key uncertainties, and associated knowledge gaps based on the rapidly evolving CI context/scene. By providing an unbiased and objective perspective on proposed climate interventions and identifying and promoting best practices for research, we aim to foster rigorous, transparent, and globally inclusive research to further our understanding of CI and its implications. Only by advancing our understanding of the Earth system’s responses to CI, will we be able to provide the basis for well-informed climate policies, potential future CI governance, including litigation.

Please direct your queries on this LHA to the WCRP Secretariat contact point Hindumathi Palanisamy (This email address is being protected from spambots. You need JavaScript enabled to view it.)

Interim Scientific Steering Group

Name Function Affiliation Country
Nadine Mengis Co-Chair GEOMAR Germany
Daniele Visioni Co-Chair Cornell University USA
Miranda Boettcher Member SWP, Berlin Germany
Nana Ama Browne Klutse Member University of Ghana Ghana
Ines Camilloni Member University of Buenos Aires Argentina
Jim Haywood Member University of Exeter UK
Peter Lawrence Member UCAR USA
Chris Lennard Member Univ. Of Cape Town South Africa
Andrew Lenton Member CSIRO and CDRMIP Australia
Lisa Miller Member SOLAS Canada
Julia Pongratz Member Univ. Munich and lead of CDRterra Germany
Romaric Odoulami Member African Climate and Development Institute South Africa
Karen Rosenlof Member NOAA USA
Roland Séférian Member CNRM France


Climate intervention

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