Modeling Climate Change - Scenario CMIP7
The Art
The Science
The Scenario Model Intercomparison Project for CMIP7
“Editorial Statement: This article describes the design of the next version of emission scenarios that will be used for the 7th phase of the Coupled Model Intercomparison Project, which in turn will be used for the 7th Assessment Report of the Intergovernmental Panel on Climate Change. It provides the story lines for the creation of the emission scenarios and therefore it envisions future trajectories of policies and energy use. Models in CMIP 7 will use these scenarios to run simulations of future climate change using the scenarios as the main forcing. The authors carefully considered all community comments and maintained an open approach to develop these scenarios
Short Summary: We propose a set of seven plausible 21st century emission scenarios, and their multi-century extensions, that will be used by the international community of climate modeling centers to produce the next generation of climate projections. These projections will support climate, impact and mitigation researchers, provide information to practitioners to address future risks from climate change, and contribute to policymakers’ considerations of the trade-offs among various levels of mitigation.
Figure 1 Proposed scenarios for CMIP7 ScenarioMIP, showing (a) GHG emissions pathways as a function of time for each of the proposed scenarios (based on GWP-100) and (b) the associated global average temperature outcomes using the probabilistic FaIR ensemble used in IPCC AR6 (Smith, 2025; Smith et al., 2024). The shaded area for emissions shows ±8 GtCO2around the expected marker scenario value while for temperature outcomes, it shows the 33–67 percentile range of the distribution for the same expected marker scenario. […] Scenarios are (H) High, (HL) High-to-Low, (M) Medium, (ML) Medium-to-Low, (L) Low, (LN) Low-to-Negative and (VL) Very Low. The final emission trajectories will depend on the finalized IAM runs but are expected to be roughly consistent with the illustrations provided here. The final temperature outcomes will be known only at completion of Earth system models' experiments, and will, for this phase of ScenarioMIP, include also the effects of carbon cycle feedbacks. …
…The overall set of scenarios covers a plausible range of global emissions in 2100, from around −10 to −20 GtCO2 yr−1 up to levels of about a third greater than today's emissions. It is expected that the temperature results from the scenarios range from around 1.5 to almost 3.5 °C increase in 2100 over the 1850–1900 level….”
The Scenario Model Intercomparison Project for CMIP7 (ScenarioMIP-CMIP7), Van Vuuren, D. P., O'Neill, B. C., Tebaldi, C., Sanderson, B. M., Chini, L. P., Friedlingstein, P., Hasegawa, T., Riahi, K., Govindasamy, B., Bauer, N., Eyring, V., Fall, C. M. N., Frieler, K., Gidden, M. J., Gohar, L. K., Högner, A., Jones, A. D., Kikstra, J., King, A., Knutti, R., Kriegler, E., Lawrence, P., Lennard, C., Lowe, J., Mathison, C., Mehmood, S., Nicholls, Z., Prado, L. F., Zhang, Q., Rose, S. K., Ruane, A. C., Sandstad, M., Schleussner, C.-F., Seferian, R., Sillmann, J., Smith, C., Sörensson, A. A., Panickal, S., Tachiiri, K., Vaughan, N., Vishwanathan, S. S., Yokohata, T., Zecchetto, M., and Ziehn, T.: The Scenario Model Intercomparison Project for CMIP7 (ScenarioMIP-CMIP7), Geosci. Model Dev., 19, 2627–2656, https://doi.org/10.5194/gmd-19-2627-2026, 2026.
Received: 05 Dec 2024 – Discussion started: 30 Jan 2025 – Revised: 09 Dec 2025 – Accepted: 07 Jan 2026 – Published: 07 Apr 2026
CMIP7 differs from the previous model in eliminating the most extreme high emissions scenario and also strongly suggests the difficulty in achieving the lowest emissions goal of not more than 1.5°C over 1850-1900 levels.
That the featured art is derived from the overlay of graph (a) -greenhouse gas emissions over time, over graph (b) - temperature change over same time period, emphasizing the correlation and interdependency of the two models.
