Contribution to IPCC AR7

Call for Global, Regional and National Scenarios

to make data available in support of the next IPCC assessment

Authors of the upcoming 7th Assessment Report of the IPCC (AR7) have written two open letters (Zenodo 20419069; Zenodo 20356173) encouraging the submission of scenario data to community databases. They highlight the Scenario Compass Initiative submission portal for global scenarios as well as parallel activities for national and regional scenarios (e.g., Africa, Latin America, South Asia, EU).

Below, you can find more information for the following calls, or directly go to the “sandbox” through which scenario data can be submitted:

• Global scenarios of emissions and socioeconomic development in an economy-wide and/or sectoral context → sandbox.scenariocompass.org
• National and regional scenarios of emissions and socioeconomic development in an economy-wide and/or sectoral context, coordinated by the IAMC Scientific Working Group on National Scenarios → national-sandbox.scenariocompass.org

Submitting scenario data to these databases is voluntary. The IPCC aims to assess all available peer-reviewed literature on scenarios regardless of whether the underlying data have been submitted to any database (see the section on use of scenario data in IPCC reports below). Those who submit scenarios retain full rights over their own data. Submission does not restrict any use or sharing by the original data producers. Submission to the database does not guarantee that any particular scenario will be included in the IPCC assessment or highlighted in any specific figure or table.

The Scenario Compass Initiative is thrilled to support the assessment for the next IPCC report!

What scenario data to submit?

In general, all submissions are encouraged. For scenarios to be considered for a quantitative assessment the following elements are helpful in facilitating specific comparisons in the report:

• Model-based: the scenario must be developed by a formal quantitative model (e.g. integrated assessment model, energy-economy model, general or partial equilibrium model, systems dynamics model, energy system optimization model, or comparable formal approach).
• Temporal coverage: to inform mitigation efforts assessment, the scenario must extend to at least the year 2040 (2100 or beyond is preferred).

Specific highlighted topics would include (this list may be updated):

• Scenarios not following a middle-of-the-road, current-trends-extended socioeconomic trajectories
• Scenarios exploring equity and justice
• Scenarios enabling cross-Working Group integration
• Scenarios exploring overshoot

When to submit?

The authors of the Seventh Assessment Report WGIII Chapter 3 write:

For the First Order Draft of the WGIII contribution to the Seventh Assessment Report, we can consider submissions until 29 September 2026. Scenarios submitted later than this date will be considered for the Second Order Draft in 2027. A more detailed timeline will follow when the timeline for the Second Order Draft will be decided.

Scenario Use in IPCC reports

All scenarios submitted to the database may be considered for inclusion in the IPCC’s Seventh Assessment Report (AR7), but submission to a database does not guarantee that any particular scenario will be included in an assessment report or highlighted in any specific figure or table. The decision on which scenarios to use for specific parts of the assessment rests entirely with the AR7 authors, based on the needs of the assessment and the quality and relevance of available data. Scenarios will not be excluded from the database, but some scenario data may be flagged as ‘not fit-for-purpose’ for parts of the IPCC Assessment Report. How exactly such ‘fit-for-purpose’ tests would be done remains up to IPCC authors and such decisions cannot be fully anticipated in this call text.

However, scenarios submitted through the Scenario Compass Initiative and the related activity for national and regional scenarios coordinated by the IAMC Scientific Working Group on National Scenarios means that:

• Authors can efficiently compare scenarios across models and studies using consistent variable definitions, units, and data formats.
• Systematic metadata enables categorisation and filtering by warming outcome, socio-economic assumptions, technology portfolio, policy assumptions, and other dimensions.
• Data availability in a structured format supports reproducibility and transparency of the assessment.

This call is issued by a group of scientists to support IPCC authors in their work. It signifies a community effort. It is not issued by the IPCC. The open letter aims to indicate to communities how they can make their data available by highlighting an open community database resource that is designed to support a comprehensive and consistent assessment.

A comprehensive overview of scenarios and modelling methods used by Working Group III of the IPCC’s Sixth Assessment Report (AR6) is available in Annex III.

Data Licensing

The following principles are adopted for both the scenario submission and public release:

• Public release of the scenario data in the Scenario Compass database: Scenario data submitted to the Scenario Compass Initiative will be accessible under community-standard licensing terms (similar to the AR6 ensemble), where data can be reused in scientific analysis but redistribution is restricted. By transferring their work to the Scenario Compass database, researchers agree that their data will be made available under these terms.
• Submission to the Scenario Compass Sandbox: Scenarios are first submitted to the Scenario Compass Sandbox by the modelling teams. Upon submission, modellers indicate whether the scenario is submitted for public use or just for testing purposes. All scenarios that are for public use go live immediately. Scenarios need to have some documentation to go public. This process allows modellers to first evaluate their scenarios with the SCI validation and feasibility/sustainability flagging information, and to use post-processing workflows including the climate-assessment categorization on preliminary work. Also after testing, modelling teams can choose to transfer their scenarios from the Sandbox to the public Scenario Compass database (see above).
• Full rights retained: Modelling teams retain full rights over their own data. Submission to the Scenario Compass Initiative does not restrict any use, sharing, or publication of the data by the original producers.
• Preliminary data handling: Scenario data that has not yet been published may be shared with AR7 authors in advance of public release, consistent with the IPCC’s procedures for handling unpublished literature. Scenario authors may request that preliminary data not be made publicly available until the associated publication is accepted. Once the scenario is in its final published form, it will be released as part of the public Scenario Compass database.
• Attribution: All users of scenario data from the Scenario Compass Initiative are expected to cite the original data source (model, team, and associated publication) and the Scenario Compass Initiative.

These terms represent a departure from the AR6 database, where data was accessible only through the primary sources until the report was published. The shift to public release of relevant scenarios upon acceptance of a corresponding manuscript or publication of a report follows the recommendations for transparency, reproducibility, and broad scientific engagement.