SSP Scenario Database

The Shared Socioeconomic Pathways (SSPs) will be used alongside the Representative Concentration Pathways (RCPs) to analyze the feedbacks between climate change and socioeconomic factors, such as world population growth, economic development and technological progress. IIASA began work in 2011 on quantifying one of the five SSPs. The Energy Program has spearheaded the cross-program collaboration with the Population and Ecosystem Services Management programs.

The SSP database aims at the documentation of quantitative projections of the so-called Shared Socioeconomic Pathways (SSPs) and related Integrated Assessment scenarios. The SSPs are part of a new framework that the climate change research community has adopted to facilitate the integrated analysis of future climate impacts, vulnerabilities, adaptation, and mitigation. Information about the scenario process and the SSP framework can be found in Moss et al. (2010), Arnell et al. (2011), van Vuuren et al. (2012) and Kriegler et al. (2012). The framework is built around a matrix that combines climate forcing on one axis (as represented by the Representative Forcing Pathways) and socio-economic conditions on the other. Together, these two axes describe situations in which mitigation, adaptation and residual climate damage can be evaluated.

The SSP quantifications build upon the collaborative effort between the IAV and IAM community, which has met in a series of meetings and identified a limited set of five SSP storylines/narratives (O‘Neill et al, 2012). The narratives describe the main characteristics of the SSP future development pathways. They served as the starting point for the identification of internally consistent assumptions for the quantification of SSP elements. Different modeling tools can be used to develop quantifications of these storylines, including factors like population, economic development, land use and energy use.

Currently (March 2013), the database includes projections for population and economic development, which are the elements that are most used as basis of both integrated assessment and IAV studies. Specifically, for the following elements quantifications are available:

  1. population by age, sex, and education;
  2. urbanization; and
  3. economic development (GDP)

For each SSP a single population and urbanization scenario, developed by the International Institute for Applied Systems Analysis (IIASA) and the National Center for Atmospheric Research (NCAR), is provided. For GDP, three alternative interpretations of the SSPs by the teams from the Organisation for Economic Co-operation and Development (OECD), the International Institute for Applied Systems Analysis (IIASA) and the Potsdam Institute for Climate Impact Research (PIK) have been developed. The GDP projections are based on harmonized assumptions for the interpretation of the SSP storylines in terms of the main drivers of economic growth. They differ however with respect to the employed methodology and outcomes. It is recommended to use the GDP projections by all teams to test the sensitivity of the results due to different GDP assumptions. In case users can only use one interpretation of the SSPs, for each SSP a single ‘illustrative’ case has been selected. The ‘illustrative’ SSP should not be interpreted as the central or representative case. In the selection of the ‘illustrative’ cases, we have currently selected all SSPs from one team (OECD). For selecting the illustrative cases a choice had to be made between increasing the representativeness of the set as a whole and ensuring the comparability of the SSPs over time and at finer spatial resolution for single countries and/or regions. For the time being, these consideration have led to the selection of all illustrative cases from a single team. For the final release, illustrative cases from more than one team might be selected also based on the external review comments.

Please note that the projections for the different SSPs are constructed such that they provide a consistent and plausible range for the combined set of variables. While we have aimed to represent a wide range of possible futures, this might not hold for every possible factor (e.g. income convergence). In a more extensive note availabe here we document some important factors of the SSPs, in particular

  1. brief summaries of the SSP narratives, and
  2. methods and assumptions that were used for the development of the SSP population, urbanization, and GDP projections.

The database will be extended in due course also with SSP-based IAM scenarios. The SSP database has been established by the Working Group on “Quantitative SSP Data and IAM Scenarios” of the joint IAV-IAM Committee to coordinate the development of new socio-economic scenarios more info. All SSP information that is provided on this website is preliminary and work in progress. The data has undergone extensive internal and external review. First preliminary SSPs were made publicly available in May 2012, and were subsequently updated in March 2013 in response to a community review.

Print this page

Last edited: 20 April 2021


Keywan Riahi

Program Director and Principal Research Scholar Energy, Climate, and Environment Program

Principal Research Scholar Integrated Assessment and Climate Change Research Group - Energy, Climate, and Environment Program

Principal Research Scholar Pollution Management Research Group - Energy, Climate, and Environment Program

Principal Research Scholar Sustainable Service Systems Research Group - Energy, Climate, and Environment Program

Volker Krey

Research Group Leader and Principal Research Scholar Integrated Assessment and Climate Change Research Group - Energy, Climate, and Environment Program

SSP Database

The preliminary results of the SSP Scenarios

International Institute for Applied Systems Analysis (IIASA)
Schlossplatz 1, A-2361 Laxenburg, Austria
Phone: (+43 2236) 807 0 Fax:(+43 2236) 71 313