A new scenario framework for climate change research: the concept of shared socioeconomic pathways

TLDR

The authors propose a new scenario framework that integrates future radiative forcing pathways with alternative socioeconomic development pathways, introducing Shared Socioeconomic Pathways (SSPs) for climate change impact, adaptation, and mitigation research. SSPs are defined as century‑scale reference pathways describing plausible societal and ecosystem trends absent climate change or policy, designed to span a space of adaptation and mitigation challenges, with an iterative process for refining basic and extended SSPs. Comparing SSP narratives to the Special Report on Emissions Scenarios (SRES) shows that SSPs can be anchored to existing scenario stories, providing a starting point for further development.

Abstract

The new scenario framework for climate change research envisions combining pathways of future radiative forcing and their associated climate changes with alternative pathways of socioeconomic development in order to carry out research on climate change impacts, adaptation, and mitigation. Here we propose a conceptual framework for how to define and develop a set of Shared Socioeconomic Pathways (SSPs) for use within the scenario framework. We define SSPs as reference pathways describing plausible alternative trends in the evolution of society and ecosystems over a century timescale, in the absence of climate change or climate policies. We introduce the concept of a space of challenges to adaptation and to mitigation that should be spanned by the SSPs, and discuss how particular trends in social, economic, and environmental development could be combined to produce such outcomes. A comparison to the narratives from the scenarios developed in the Special Report on Emissions Scenarios (SRES) illustrates how a starting point for developing SSPs can be defined. We suggest initial development of a set of basic SSPs that could then be extended to meet more specific purposes, and envision a process of application of basic and extended SSPs that would be iterative and potentially lead to modification of the original SSPs themselves.