Valentin STUHLFAUTH
Author
Last week, the third Scenario Forum (external link) was held at the University of Leeds, a gathering where researchers shape the climate futures that will inform the world' s most influential global assessment reports: the IPCC (external link) and IPBES (external link). Behind the scenes, one thing became clear: the models designed to envision our collective future are still failing to include the radical change needed to keep the planet liveable for today’s and future generations.
This year’s forum expanded on advancing the use of Shared Socioeconomic Pathways (SSPs)-Representative Concentration Pathways (RCPs) framework that underpin IPCC modelling, and included exploration of the transformative potential of scenarios that address health, inform policy and open-up new possibilities for the future, ahead of the next Coupled Model Inter-comparison Project (external link) (CMIP7). There was even talk of rebranding the long-confusing RCPs under the simpler label “climate dimension”. But, let’s be: cosmetic modifications can’t fix the deep conceptual tensions baked into the SSP-RCP framework used by the IPCC.
Behind these acronyms lies a persistent problem: large Economy-Environment models don’t model justice (external link) . They cannot show what a world deliberately organized around equity (between and within countries, generations, or communities) might look like. This omission is all the more striking given that the IPCC’s own AR7 chapter outline (external link) explicitly mandates an exploration of “the relationship(s) between equity, justice, and mitigation across, between and within countries and generations”. Yet when forum organizers were pressed on how they would incorporate equity into their modelling, the response was sobering, revealing that these critical dimensions remain on the margins of the so-called IPCC climate scenarios.
Let that sink in. Calls for justice, redistribution, or systems change are not debated, they are simply dismissed. “Perfect equity scenarios do not exist,” said one participant. “Equity and mitigation are orthogonal goals,” claimed another. And for colleagues working on post-growth pathways, the message was blunt: “too unrealistic.”
This kind of reasoning preserves the SSP-RCP structure by sidelining anything too transformative. Equity is treated not as a modelling dimension, but as a philosophical afterthought. As Kanitkar, Mythri and Jayaraman argued in their 2024 assessment (external link) : "Integrated Assessment Models predict inequality not because it's inevitable, but because they refuse to model anything else".
The IPCC claims, based on its mandate (external link), to be policy-relevant but not policy-prescriptive. But that’s a myth. In practice, what gets modelled is what gets considered politically plausible, and what is left out of modelling shapes real-world action. As one speaker aptly pointed out during the opening plenary: "the IPCC effectively prescribes what is considered possible".
IPCC reports are performative (external link); they don’t just reflect futures, they manufacture them (external link) and shape public discourse, policymaking, and real-world outcomes. Excluding upfront equity because it’s “unrealistic” is to deny its very possibility. Equity is not an analytical choice. It is a political and ethical one.
If realism is the bar, then let’s use it consistently. Carbon Dioxide Removal (CDR) (external link) technologies like BECCS and Direct Air Capture (external link), routinely feature in the so-called IPCC scenarios, despite their technico-financial implausibility, lack of social acceptance and ecological risks. The myth of decoupling GDP growth from emissions (external link) has been thoroughly debunked, yet it still underpins the global climate mitigation scenarios considered in IPCC assessment reports. Meanwhile, equitable post-growth models are cast out. The real question for the IPCC to answer is: whose realism, and whose future, will AR7 represent?
Ironically, the IPCC was described at the forum as primarily a “literature review exercise”. Meanwhile, IPBES, the biodiversity focused sibling institution, was praised for “doing research” via analytical frameworks. If that’s the case, then why are transformative, peer-reviewed pathways left out of IPCC modelling work?
The answer may lie in the authorship concentration. The IPCC is dominated by institutions and researchers from a handful of Western countries. If its role is to synthesize global knowledge, it must diversify its sources and frameworks or risk turning the modelling exercise into a performative ritual of consensus rather than a tool for planetary survival.
If the IPCC’s scenario architecture is to live up to its mandate, it must open-up to equity, post-growth, to new imaginaries of sufficiency and care. This means no longer outsourcing “justice” to the footnotes. It means embracing the scientific plurality of our times.
And let’s be clear, this transformation is not optional. It is necessary.