The international scientific process that supplies climate scenarios for the Intergovernmental Panel on Climate Change (IPCC) has formally dumped the controversial high-emissions “RCP8.5” and “SSP5-8.5” warming pathways that dominated global climate research and policy discussions for more than a decade.
The change comes through the CMIP7 ScenarioMIP framework, developed under the Coupled Model Intercomparison Project (CMIP), the global modelling collaboration that provides the future climate projections used throughout Intergovernmental Panel on Climate Change (IPCC) assessment reports. The new scenario framework will underpin the IPCC’s upcoming Seventh Assessment Report (AR7).
In a newly released paper, ScenarioMIP researchers wrote that the previous high-end emissions pathway “has become implausible” because of changing emissions trends, technological developments and existing climate policies. The paper states: “For the 21st century, this range will be smaller than assessed before: on the high-end of the range, the CMIP6 high emission levels (quantified by SSP5-8.5) have become implausible.”
The now-retired scenarios — including RCP8.5, SSP5-8.5 and SSP3-7.0 — were widely used across IPCC-linked research, government climate assessments, central bank stress testing, insurance modelling and international policy analysis. For years, the pathways were frequently presented as “business as usual” futures involving massive fossil fuel consumption and extreme population growth.
Science and policy commentator Roger Pielke described the development as “an absolutely huge development in climate science,” arguing the modelling pathways had shaped “tens of thousands of research papers,” legacy mainstream media reporting and policy frameworks worldwide. He wrote that “the scenarios that have dominated climate research, assessment, and policy during the past two cycles of the IPCC assessment process are implausible.”
Pielke argued the change has major implications because many governments and institutions built policy around the scenarios. He pointed to climate assessments in countries including the United States, United Kingdom, Germany, Canada, Australia and Japan, along with financial stress-testing systems used by central banks and regulators.
The CMIP process itself operates independently of the IPCC but is deeply intertwined with it. CMIP develops the emissions pathways and climate model experiments that are then assessed and synthesised by IPCC working groups. ScenarioMIP, a specialised branch within CMIP, is responsible for creating the socioeconomic and emissions scenarios used in those projections.
Climate policy critic Electroverse said the “panic pathway” had fuelled years of catastrophic headlines involving “drowned cities, crop collapse, mass death and economic ruin,” while influencing Net Zero policy, insurance warnings and school material. The scenarios had now been downgraded to “an extreme ‘what-if’ exercise” rather than a realistic projection of the future.
While the new CMIP7 framework removes the most extreme pathways from its central modelling structure, debate remains over whether the replacement “HIGH” and “MEDIUM” scenarios are still too pessimistic compared with current emissions and energy trends. Pielke argued the revised framework was “a real course correction” but said “the plausibility vacuum at the heart of the architecture has yet to be addressed.”
IPCC scientists have just ditched one of the climate establishment’s favorite tools. “RCP 8.5” (the red-hot pathway used in tens of thousands of climate studies) has now been judged “implausible.”
For years, this unrealistic scenario, based on extreme fossil fuel use and… pic.twitter.com/k6B3ZPFnjs
— Electroverse (@Electroversenet) May 6, 2026
Image credit: redcharlie
