Presentations highlighted the achievements of the first phase of the project, CORDEX-I, a successful framework in which scientists around the world adopted a common protocol to guide the development of a high-resolution Regional Climate Model (RCM) and of empirical statistical downscaling projections. The project included an intercomparison of those projections for each continent. The conference provided evidences that much of the work underway is relevant to the climate change vulnerability as well as impacts and adaptation studies. However, CORDEX needs to address several key challenges in order to better serve its priorities. The participants recognized:
- that two-way dialogue had to be established with decision-makers in order to tailor CORDEX outputs to their needs;
- the need for training and capacity building among practitioners, policymakers, scientists and other decision-makers;
- the importance of high-resolution observational data sets and archiving infrastructures such as the Earth System Grid Federation in support of the evaluation of regional climate projections; and
- the lack of mechanisms to communicate the scientific uncertainty generated by a regional climate model and the implications that those uncertainties can have in the application of the resulting regional climate information on vulnerability, impacts and adaptation studies.
Some scientists outside the CORDEX community argue the capability of dynamic downscaling to add accurate information beyond what would be achieved just by interpolating global model prediction onto a finer scale terrain or landscape map. Thus, the participants also discussed the added value of the regional downscaling numerical models and agreed on the need to rigorously demonstrate the reliability and usefulness of the CORDEX outputs and to improve the representation of the physical processes in these models.
The Conference proposed concrete actions for further advancing CORDEX:
- revisit the CORDEX priorities and develop a clear-science based procedure for their selections;
- develop metrics to assess the added value of the regional downscaling model outputs as compared to global climate simulations;
- support the development of high-resolution observation data sets for assessing the robustness of the models;
- establish end-to-end pilot studies over selected sub-regions as test-beds for exploring a range of critical issues together with other World Climate Regional Programme regional initiatives and in partnership with its Working Group on Regional Climate; and
- design and implement capacity building activities that bring information providers together with decision-makers on regional level to define local need.
The future simulation framework resulting from the implementation of these actions might form the second phase of CORDEX (CORDEX-II) and will represent another milestone in the delivery of climate services.