The figure shows an Australian heat wave as an example use of the C20C+ model output by the CASCADE Detection and Attribution team. We first apply a number of tests to ensure that the model and observational data are “fit for purpose” for attribution purposes (middle panel). The right panel shows the distribution of each 300 member ensemble for the world that was (red) and the world that might have been (blue) showing a clear shift towards higher temperature. Thus the odds of the actual heat wave have increased.

Recent C20C+ highlights include:

• Completion of actual and counterfactual 50 member ensembles from 1960-2013 using the Community Atmospheric Model, CAM5.1.
• Completion of an additional 250 ensemble members for each CAM5.1 experiment from 2011-2013.
• Distribution of CAM5.1 model output on the Federated Earth System Grid.
• Acquisition of C20C+ model data from the Japanese modeling group, MIROC.