Equitable cooperation explorer

What is on this page. The cards cover the energy-system, land and emissions indicators that the paper's scenarios resolve, in this order: emissions and transfers, renewable capacity, final energy and efficiency, coal power, energy-system CO₂, non-CO₂ gases and methane, emissions by sector, fossil supply, renewable generation, low-emission electricity, hydrogen, carbon storage, land-use CO₂, then transport. Indicators that exist only as historical series, such as vehicle sales or fossil fuel subsidies, are not reported by scenario models and are not shown.

Fair shares and carbon debt. Each region receives a share of the carbon budget under a fairness principle. A region whose cumulative emissions exceed its allocation carries a carbon debt. It can pay the debt down by cutting emissions faster at home, by removing emissions at home, or by financing action in other regions.

The two corners. Under unlimited transfers (U, up-pointing triangle in the paper figures) finance between regions is unlimited, the physical transition matches the cost-effective source pathway, and the fair share is settled by financial transfers. Under lowest transfers (L, down-pointing triangle) finance is held to the lowest level at which the model remains feasible, the higher-responsibility regions cut fossil fuels faster at home, and the regions with less historical responsibility gain room relative to the source pathway. A cross marks the source pathway.

The fair-share variants. ECPC shares the budget by equal cumulative emissions per person, CAPC adjusts that share for capability, and the year is when responsibility starts to count (1990, 2015 or 2025). ECPC 2015 on the SSP2 narrative, the paper's reference case, is selected at first. ECPC 2015* is ECPC 2015 with a ten-year delay before transfers begin. Further pairs change the narrative (SSP1), the cooperation channel (novel carbon removal only) or the discount rate (1%). Each pair has both corners.

The carbon budgets. Two budgets, both counted from 2020 and both allowing overshoot: one consistent with about 2 °C at a two-in-three chance and one with 1.5 °C at an even chance. The budget binds the emissions the fair-share rules cover. Land use, international shipping and aviation sit outside it, so total CO₂ over 2020 to 2100 lands within a few percent of the budget for every line.

Transfers, investment and consumption. Transfers and investment are present values at 2025 of flows from 2026, in market exchange rate dollars. Consumption changes are the same present value against the no-new-policy baseline or against the source pathway.

Separate comparison run, for orientation only. The Low marker pathway of the ScenarioMIP-CMIP7 scenario set is a MESSAGEix-GLOBIOM-GAINS run (SSP2, Low Emissions) and the nearest public MESSAGEix pathway to the 2 °C source. It is shown so that the paper's scenarios can be placed against a published CMIP7 pathway from the same model. Switch it on to see the same indicators from that run for the World and for every region. * The series drawn here are not the ScenarioMIP series as reported: the harmonised release starts in 2023, so for 2020 to 2025 the cumulative CO2 figure uses our source scenario, which follows the same history before the first model timestep in 2030; regional series are the model's native reporting rather than the harmonised release. For the scenario data itself, use the IIASA ScenarioMIP explorer at scenariomip.apps.ece.iiasa.ac.at. Cite: Riahi, K., van Vuuren, D.P., et al. (in preparation), Overview of the Socioeconomic, Emissions and Land Use Futures of the ScenarioMIP-CMIP7 Pathways; scenario data Riahi, K., van Vuuren, D.P., et al. (2026), Scenario data of the ‘Socioeconomic, Emissions and Land Use Futures: The ScenarioMIP Pathways for CMIP7’, release v0.1, Zenodo, doi:10.5281/zenodo.22296051, CC BY 4.0; framework van Vuuren, D.P., O'Neill, B.C., Tebaldi, C., et al. (2026), The Scenario Model Intercomparison Project for CMIP7 (ScenarioMIP-CMIP7), Geoscientific Model Development 19, 2627, doi:10.5194/gmd-19-2627-2026; the Low marker run Fricko, O., Wu, Y., Zhang, S., et al. (2026, to be submitted), listed with the other model papers at scenariomip.apps.ece.iiasa.ac.at/documentation.