For the single month of December 2010, the HadGEM3-A-based attribution system estimates that the ratio of probabilities P1/P0 lies between 0.06 and 1.00 (5th-95th percentiles) with a median of 0.27 when HadGEM1 SSTs are used and between 0.05 and 0.79 with a median of 0.23 when HadGEM2...