Releases

This release compiles the scenarios from release v1.1 (August 5, 2026) as well as the ScenarioMIP scenarios (release v0.1, September 1, 2026) and all scenarios submitted to the SCI Sandbox and requested to be transferred until early October 2026. Specifically, more than 300 scenarios including results from the model-comparison project ELEVATE and from 20 single-model studies submitted by 15 modelling teams.

All scenarios were assessed using the latest available version of the simple climate model MAGICC (v7.6.0a3), based on emissions-harmonization using reference data up to 2023. Scenarios were also evaluated using the criteria for historical vetting and feasibility/sustainability flagging (2026-08-03, https://scenario-evaluation-criteria.iamconsortium.org/2026.08.03/). See also the related Python package at https://scenariocompass.readthedocs.io/.

Scenarios were categorized according to their temperature pathways as described in Riahi et al. (2026), see https://scenariocompass.org/methodology/categories.

This release compiles the scenarios from release v1.1 (August 5, 2026) as well as the ScenarioMIP scenarios (release v0.1, September 1, 2026).

This release updates the initial release v1.0 (February 16, 2026) with the following changes:

• All scenarios were assessed using the latest available version of the simple climate model MAGICC (v7.6.0a3), based on emissions-harmonization using reference data up to 2023.
• The climate categorisation (see Riahi et al. (2026), see https://scenariocompass.org/methodology/categories) was redone using the updated climate assessment MAGICC v7.6.0a3 instead of MAGICC v7.5.3 used in release v1.0.
• Scenarios were evaluated using the criteria for historical vetting and feasibility/sustainability flagging (2026-08-03, https://scenario-evaluation-criteria.iamconsortium.org/2026.08.03/). See also the related Python package at https://scenariocompass.readthedocs.io/.

This release includes all scenarios from the ensemble used for the IPCC's Sixth Assessment Report (Byers et al., 2022, doi: 10.5281/zenodo.5886911) that had sufficient information for climate-assessment as well as scenarios published until the end of 2025 that were submitted to the SCI Sandbox.

All scenarios were assessed with respect to their temperature diagnostics using the same setup as used for AR6, specifically the same emissions harmonisation and the climate model MAGICC v7.5.3.

Scenarios were also evaluated using the criteria for historical vetting and feasibility/sustainability flagging as described in the Supplementary Material of the first submission of the SCI manuscript (Riahi et al., 2026, doi: 10.21203/rs.3.rs-8891091/v1).