Building SSPs for Climate Policy Analysis: A Scenario Elicitation Methodology to Map the Space of Possible Future Challenges to Mitigation and Adaptation

TLDR

The scientific community is developing Shared Socio-economic Pathways (SSPs) to replace SRES scenarios, requiring contrast along mitigation and adaptation challenge axes. This paper proposes a backward approach to select the most relevant SSPs from a large model database for specific decisions. The method identifies drivers of mitigation and adaptation challenges, generates a large scenario set through modelling, and then selects a few SSPs that span the uncertainty space, enabling decision‑specific scenario choice.

Abstract

The scientific community is now developing a new set of scenarios, referred to as Shared Socio-economic Pathways (SSPs) to replace the SRES scenarios. To be used to investigate adaptation and mitigation, SSPs need to be contrasted along two axes: challenges to mitigation, and challenges to adaptation. This paper proposes a methodology to develop SSPs with a “backward” approach. The methodology is based on (i) a priori identification of potential drivers of mitigation and adaptation challenges; (ii) a modelling exercise to transform these drivers into a large set of scenarios; (iii) a posteriori selection of a few SSPs among these scenarios, such that they cover the uncertainty space in terms of challenges to adaptation and mitigation. This methodology is applied to the selection of a few SSPs, but it could also be applied to any specific decisions faced by decision-makers. From a large database of runs built by many models, the methodology would allow selecting the most relevant scenarios for a specific decision, i.e. scenarios that best predict when the analyzed choice performs poorly or well.