Scientific Working Group on Scenarios

Co-chairs: Tom Kram (PBL),  Keywan Riahi (IIASA) and Detlef van Vuuren (PBL)

Development and analysis of global to regional and country scenarios has been at the heart of integrated assessment modelling from its earliest days: scenarios to underpin the 1st Assessment Report of the IPCC were elaborated with 1st generation IAMs. The development of narrative based contrasting scenarios published in the IPCC Special Report on Emissions Scenarios [SRES,2000] was led by IAM research groups and is considered a landmark in the field. There is strong overlap between the authorship of the SRES and the IAMC Scientific Steering Group.

The establishment of the IAMC was inspired by the requirements of the evolving plans for a multi-science communities new scenarios process to support climate change research. This is strongly reflected in the discussions at the First Annual Meeting of the IAMC. The commitment of the IAMC to further research of relevance for the IPCC in conducting its assessment work was consolidated by a Memorandum of Understanding between the two bodies.

It is anticipated that many IAMC member organizations will contribute to, and use results of, the ongoing new scenarios process. As described in [Moss, 2012], this process bridges three scientific communities each linked with one of the IPCC Working Groups: climate modelling (CM-WG1); impacts, adaptation and vulnerability analysis (IAV-WG2); and emissions and mitigation analysis (IAM-WG3). To facilitate communication between the three communities, and to interact with IPCC WGs, the SWG on Scenarios performs that role on behalf of the IAMC. The SWG also coordinates the development of community scenarios (such as the RCPs and IAM SSP scenarios) and informs the IAMC SSC and other members about progress, ongoing and planned activities, and results of the scenario development activities.


The primary goal of the working group is to ensure that expertise, data and models available in IAMC member organizations are used in support of development and elaboration of new generations of scenarios for climate change and sustainability research. To this end, the SWG will act on behalf of the IAMC to 1) co-ordinate the development of new community scenarios within the IAMC and 2) to co-ordinate the communication and exchange with the other two scientific communities on issues related to (community) scenarios (CM/ESM and IAV).

More specifically, the SWG will solicit input from, and communicate insights and results to, members of the IAMC; and participate in joint activities of the CM, IAV and IAM communities to develop joint integrated research agendas and recommendations, and other activities pertinent to development and application of new generations of scenarios for climate change research.

Planned Activities & Organization of Work

The Scientific Working Group on Scenarios:

  • Leads and coordinates the IAM communities’ efforts on implementation and publication of so-called “representative” IAM marker scenarios based on the SSPs; and possible follow-up activities. The work is conducted in close co-operation with ICONICS and other experts.
  • Serves as contact point on scenario-related topics between the IAMC and ICONICS and contributes to other activities of ICONICS, such as multi-scale applications; IAV handshaking, scenario extensions, e.g. Shared Policy Assumptions; scenario updates and revisions; and possibly the use of climate data in the integration phase of the new scenario process.
  • Serves as contact point between ScenarioMIP and the IAM community, including for the purpose of providing input to ScenarioMIP on recommendations for CMIP6 experiments and associated requirements for input from IAMs to ESMs.
  • (Co-)organizes meetings and workshops related to community scenarios (in particular the SSPs) with the aim to facilitate communication between IAM experts, and between IAM experts and the other research communities.
  • Organize regular telecalls to organize and coordinate IAM scenarios development and related review processes.
  • Keeps the IAMC informed on progress with key milestones and on proposed activities via updates of the website and at the annual meetings.

 Anticipated Time Period of the SWG

The SWG is in fact already operational for several years, subject to approval by the SSC. An appropriate end time is not easy to give as scenario activities are bound to continue during 2015 and beyond, including, for example, to prepare the required IAM data inputs for the ScenarioMIP in CMIP6. Several key activities listed above will take place over the next two years, and the SWG should continue at least until that time. At that point, the SWG will revisit its goals and the SSC will, at least at each annual meeting, decide on extension of the lifetime of the SWG.

Co- chairs and Members

Co-chairs: Tom Kram (PBL, co-chair of ICONICS), Keywan Riahi (IIASA, co-chair of the IAM quantification WG of ICONICS) and Detlef van Vuuren (PBL, co-chair of the IAM quantification WG of ICONICS, and co-chair of the ScenarioMIP of CMIP6).

Preliminary members of the SWG on Scenarios: Jae Edmonds (PNNL/JGCRI), Nico Bauer (PIK), Benjamin Bodirsky (PIK), Kate Calvin (PNNL/JGCRI), Johannes Emmerling (FEEM), Oliver Fricko (IIASA), Petr Havlik (IIASA), Richard Moss (PNNL/JGCRI), Elmar Kriegler (PIK), Brian O’Neill (NCAR), Shilpa Rao (IIASA), P.R. Shukla (IIMA), Steve Smith (PNNL/JGCRI ), Laurent Drouet (FEEM), Shinichiro Fujimori (NIES), Tomoko Hasegawa (NIES), Alexander Popp (PIK), Elke Stehfest (PBL), Massimo Tavoni (FEEM), Kenichi Wada (RITE), Stephanie Waldhoff (PNNL/JGCRI).

In addition, the following non-IAM experts are contributing to the activities of the scenario SWG: Jesus Crespo (IIASA), Rob Dellink (OECD), Leiwan Jiang (NCAR), Marian Laimbach (PIK), Wolfgang Lutz (IIASA), KC Samir (IIASA)

Note that participation in SWGs is open to IAMC members, please contact the co-chairs if you are interested to join:,,