Amongst the major planetary challenges of the 21st century are the interplays between climate change and the multiple dimensions of development. The specific challenge for the modeling community is to help understanding these interplays and putting some rationale in policy debates about how to simultaneously address climate change and the other “stresses” or “tensions” that might affect the sustainability of growth over the following years and of development pathways over the long run. This side-event will organize an open discussion between the key teams involved for years in IAM about how to meet this challenge. The existing tools result from long standing traditions often launched as soon as in the seventies after the first oil shock and in the context of controversies about nuclear energy. Much progress has been made since then, including thanks to greater computational power but it is time, just after the 5th IPCC report and before the COP21 which will open a new area for climate policies to discuss whether the new challenges can be addressed through a better and more extensive use of the current state-of-the-art (an improvement of the science/policy interface) or demand profound evolutions of the paradigms behind this state-of-the-art. Examples of these scientific challenges are:

• Bridging the gap between the analysis of the launching phases of climate action in adverse economic conditions and the analysis of long-term transformation pathways.
• Representing bifurcations in development pathways, with or without climate policies, which means to capture the lock-in effects of short-term behaviors
• Coupling energy models with models of urban and of land-use dynamics in a general equilibrium framework which represents the interplays between income distribution, ‘non marketed/informal’ activities, the content of technical change and growth,
• Capturing the dependence of the magnitude of the climate change impacts upon the structural fragilities and adaptive capacity of the impacted society,

The side-event will be based on a Call for contributions to researchers of the IAM community present at the Our Common Future conference. They will be asked to synthetize in a few bullet points their views of the New Frontiers for the IAM given their own vision of the scientific and policy challenges ahead about these three questions:

• What are the research questions on the interactions between climate policies and sustainable development you would want the models to address?
• What are the theoretical and methodological obstacles to overcome so that the models are able to address those questions?
• What are the major institutional or organizational barriers, internal or external to our community, to be lifted to alleviate these obstacles?

The side-event will last 2 hours and 15 minutes and will be organized as follows:
One introductory keynote (20 minutes) by N. Nakicenovic and JC Hourcade, synthesizing the received material and the lessons from the two parallel sessions.
A roundtable of reactions to this keynote by representatives of the various modeling approaches (5 minutes each, participants tbc): Ottmar Edenhofer, Riahi Keywann, Detlef Van Vuuren, John Reilly, Maryse Labriet, Pryadarshi Shukla, Emilio La Rovere, Leon Clarke, Arnulf Grübler, Steve Pye.
One hour of overall debate with the audience covering three main issues: the main scientific challenges, the methodological breakthrough to be operated, the institutional challenges for a better organization of the scientific community.