Directly following the Scenarios Workshop, on December 8-10, was the Climate Change Modeling and Downscaling Workshop, also sponsored by the Department of Energy.  Approximately 60 people attended the workshop, the focus of which was on the issues and approaches for using models and model output in the Assessment. 

The workshop kicked off with an overview of past practices and challenges associated with modeling, including spatial and temporal scales, characterizing uncertainties, and connecting climate models to impacts models. A significant topic of conversation was how to make progress in providing regional climate and socioeconomic information through a variety of approaches, including downscaling larger-scale models and building regional models.  Breakout groups and panels addressed the implications for integrated assessment models, inter-sectoral modeling, scaling issues, and which IPCC model results and other sources would be the most appropriate basis for the 2013 report.  Other discussions focused on building an aspirational view of what can be achieved with a continuing Assessment process and ways to ensure that the expectations of scientists and stakeholders are well managed in order to avoid communication issues.

Among the suggestions from individuals in the group were to 1) make sure that the 2013 report activities lead to a longer-term, rigorous modeling approach for the future; 2) start from the CMIP 3 archive, but do what is possible to compare the CMIP 3 and the CMIP 5 approaches in the 2013 report; 3) include a mitigation policy option; 4) initiate some well structured inventories of downscaling activities, including best practices in downscaling; 5) work on building “climate futures” that support the scenario development efforts for regions and sectors; 6) be very explicit about what we know and what we don’t know; and 7) develop better ways to use modeling to support inter-sectoral analysis.