Scenario Evolution Process

The Scenario Evolution Process (SEP) is a global, research community-led initiative to evaluate and update the Shared Socioeconomic Pathways (SSPs). Although the outcome of this process is not predetermined, today’s interconnected challenges demand a toolkit that reflects holistic responses to complex challenges. Whether the SSPs require a minor update or a fundamental redesign will be decided by the research and policy community.

The multi-year process (2026–2030) includes information gathering, workshops, academic publications, and other approaches to  reach consensus on the elements of the next generation of scenarios that would  better support resilient, equitable, and sustainable development. The first and most critical step in this process is understanding your perspective. The current stage of SEP is focused on gathering the baseline data that will shape our strategic direction for 2026. 

Please fill in the survey and let’s get started!

News and Updates

2 - 5 March 2026 | More SEP Q&A sessions this March

ICONICS is hosting additional Q&A sessions on the Scenario Evolution process on the 2nd and 5th of March.

To register for the Q&A sessions, please use the following links:

 

12 February 2026 | Introductory Webinar

Webinar recording: Link to recording / passcode: 67&p.C@g

Additional Q&A sessions will be held on 2 March and 5 March. See the above entry for details.

In this webinar, speakers outlined the motivation, vision, and process for SEP, including three connected activities:

  • A multi-stage survey for both scenario producers and users of scenario-based information, designed to broaden perspectives, incorporate feedback from a wide audience, and reduce Global North bias.
  • An academic literature exchange, gathering recommendations toward an updated scenario framework.
  • A series of workshops to engage with a diverse range of communities.

This launch marks the beginning of a multi-year, community-driven effort to develop more inclusive, policy-relevant socioeconomic scenarios for global climate and development research.

This website, hosted by the Pardee Institute for International Futures at the University of Denver serves as a platform for coordinating key SEP activities, including an initial global survey, which will inform subsequent workshops, academic contributions, and expert discussions. Visitors are invited to take the survey.

Timeline

Information Collection Phase

short timeline diagram

 

Overall Timeline for SEP

medium timeline diagram

 

Timeline: The Big Picture

long timeline diagram

Overview

Scenario Evolution Process (SEP) is a multi-year, community-driven initiative designed to understand how the Shared Socioeconomic Pathways (SSPs) were used andwhat the research community desires from future scenarios. This information will be used to chart  a path for an appropriate evolution from the SSPs that goes beyond climate mitigation and adaptation to integrate nature, sustainable development, and social equity into the core of the future narratives.

SEP is envisaged as a re-evaluation of the architecture of the SSPs, guided by a community-based process. Through this global survey and upcoming workshops,  the scientific community is asked to provide critical input on issues such as:

  • What domains should future scenarios apply to?
  • Should scenarios remain primarily exploratory ("what-if" thought experiments) or evolve into solution-oriented ("how-to") tools for resilience building?
  • Should pathways remain static trajectories, or should we introduce "path-switching" to model how societies might pivot in response to crises? How?
  • Should "wildcards," tipping points, and shocks (e.g., pandemics, conflicts) be included in narratives? How?
  • Is it necessary to extend time horizons beyond 2100 to capture long-term earth system feedbacks?

Who is Coordinating SEP?

The Scenario Evolution Process (SEP) is a community-wide initiative, coordinated by ICONICS (The International Committee on New Integrated Climate Change Assessment Scenarios).

The ICONICS Steering Committee

ICONICS serves as the primary coordinating body for the project. Leading experts from the Integrated Assessment Modeling (IAM) and Impacts, Adaptation, and Vulnerability (IAV), IPBES, and climate science communitiesexusre the scientific integrity and strategic continuity of the scenarios.

  • Co-Chairs: Kristie Ebi (University of Washington), Bas van Ruijven (IIASA).
  • Committee Members: Tim Carter, Edwin Castellanos, Alex de Sherbinin, Katja Frieler, Matthias Garschagen, Stephane Hallegatte, Paula Harrison, Tomoko Hasegawa, Kasper Kok, Elmar Kriegler, Brian O'Neill, Keywan Riahi, Alex Ruane, Vanessa Schweizer, Nicholas Simpson, Anna Sörensson, Kiyoshi Takahashi, Detlef van Vuuren, and Anita Wreford.
  • Support: Marina Andrijevic, Carole Green, Inga Menke, Jonathan Moyer

Commitment to Diversity

A core mandate of the SEP is to expand participation beyond the traditional research hubs. Working groups and consultations are structured to ensure representation from the Global South, gender balance, and early-career researchers, ensuring the next generation of scenarios reflects the diversity of the global community.

ICONICS Logo

ICONICS

The International Committee On New Integrated Climate change assessment Scenarios (ICONICS) develops, facilitates, and promotes the use of socioeconomic development pathways to support interdisciplinary research and assessment of climate change-related risks, and to support exploration of the effectiveness of adaptation and mitigation policies and actions across spatial and temporal scales to reduce those risks within the context of the Sustainable Development Goals.

ICONICS facilitates this mission through:

  • Vertical integration: developing and applying integrative, cross-scale, and cross-sectoral scenarios;
  • Horizontal integration: fostering interaction across scientific disciplines engaged in climate change research to develop, apply, and evaluate integrated scenarios bridging climate change, projected risks, adaptation, and mitigation; and
  • Broadening the scope: promoting adaptation and mitigation research to support achieving the Sustainable Development Goals.
Learn More About ICONICS
Pardee Logo

Pardee

The Pardee Institute for International Futures, located at the University of Denver’s Josef Korbel School of International Studies, is a research center dedicated to analyzing long-term, global, human, and social systems to improve the human condition. It utilizes the International Futures (IFs) modeling system, which forecasts data for 188 countries up to 2100 to guide policy-making on development and sustainability.

Key Aspects of the Pardee Institute:

  • Focus Areas: The institute focuses on forecasting, strategic analysis, and policy trade-offs regarding global changes in population, economics, health, and infrastructure.
  • International Futures (IFs): This core, open-access, and integrated, modeling tool combines data, system dynamics, and human insight to explore potential, long-term scenarios.
Visit Pardee Institute

Support SEP

Realizing SEP’s vision requires coordination, inclusivity, and continuity. While the process is being launched by volunteer researchers across institutions and disciplines, it urgently needs support to sustain the technical and organizational backbone necessary for success:

  • Coordination and facilitation: Enable the core team to manage the evolving, multi-stakeholder process and maintain transparency and momentum.
  • Community engagement: Support a robust series of global and regional workshops, consultations, and co-development events, especially to ensure representation from underrepresented regions and disciplines.
  • Travel and participation support: Ensure equitable participation of researchers and practitioners from across the Global South and low-income settings.

Partnership opportunities

We are seeking in-kind and financial support from partners committed to strengthening the foundations of global climate, biodiversity and development research. Contributions could include:

  • Hosting or co-organizing workshops and coordination meetings
  • Providing travel funds or participation grants
  • Supporting part-time coordination and technical staff

The SEP offers funders a unique opportunity to help shape the infrastructure of future scenario-based research—fostering an open, inclusive, and globally relevant scientific foundation for decades to come.

For more information or to discuss partnership opportunities, please contact sep@du.edu.

History of Scenarios

The scientific modeling of the Earth’s future is an exercise in navigating uncertainty. Over the past five decades, the international research community developed increasingly sophisticated frameworks to couple the dynamics of human civilization—economics, demography, and governance—with physical Earth systems.

To understand where the Scenario Evolution Process (SEP) is going, we must first understand the frameworks that informedits creation.

  • 1. Foundation

    1970s-1980s

    The conceptual bedrock of modern integrated assessment modeling (IAM) was laid in the early 1970s with the Club of Rome’s The Limits to Growth. Early models introduced the use of system dynamics to model global interactions between population, industrialization, and resources. The key insight from this era—which remains central to the SSPs today—was that the future is not a single linear forecast, but a fan of possibilities determined by policy choices and feedback loops.

  • 2. Sequential Modeling

    1990-2010

    The need for standardized inputs for climate models became acute with the establishment of the Intergovernmental Panel on Climate Change (IPCC) in 1988. This led to the "Sequential Process," where socioeconomic narratives were developed to inform emissions estimates. The estimates were input into climate models.

    • SA90 & IS92 (1990–1992): The first generation of IPCC scenarios provided essential data for early assessment reports but were often "flat," lacking deep narrative descriptions of the geopolitical or social worlds that produced the emissions.
    • SRES Revolution (2000): The Special Report on Emissions Scenarios (SRES) marked a paradigm shift. For the first time, scenarios were organized around qualitative storylines ("families" like A1, B1) rather than just numbers. This highlighted that different socioeconomic choices could lead to similar emission outcomes but vastly different capacities to adapt.

  • 3. Parallel Process & The SSPs

    2010-2025

    By the late 2000s, significant advances in science produced more information on the full range of greenhouse gas emissions at the same time that socioeconomic information in the SRES was becoming increasingly outdated.

    To resolve this, the community adopted the Parallel Process that decoupled physical climate targets (Representative Concentration Pathways, or RCPs) from socioeconomic narratives (Shared Socioeconomic Pathways, or SSPs), facilitating  multi-dimensional assessments of risk. Researchers could ask: “What does a 2°C world look like in the context of global cooperation (SSP1) versus regional rivalry (SSP3)?”. The resulting SSP-RCP Matrix became the standard for the IPCC AR5 and 6 and operational tools like the Network for Greening the Financial System (NGFS).

  • 4. Next Evolution

    2025-2030

    The SSPs were designed primarily for climate-centric research. Today’s interconnected challenges—biodiversity loss, deep inequality, and the Sustainable Development Goals (SDGs)—may require a more holistic approach.

    Current gaps identified by the community include:

    • Artificial Baselines: The concept of "no-policy" worlds is increasingly unrealistic.
    • The Equity Gap: Inequality and redistribution mechanisms are not explicitly modeled enough to answer "just transition" questions.
    • Nature & Society: Scenarios are needed to integrate nature and human well-being, not just as inputs for climate, but as goals in themselves.

    The Scenario Evolution Process is the community-led response to this mandate, moving from "Climate Scenarios" to "Holistic Socioeconomic Scenarios" for the AR7 cycle and beyond.