Region		ECHAM5-20C		ECHAM5-A1B		ECHAM5-A2
		Lower	Lambda	Upper	Lower	Lambda	Upper	Lower	Lambda	Upper
Box 1 (97.5%)	8.42	8.86	9.32	8.38	8.82	9.27	8.04	8.47	8.92
Box 2 (95%)	7.93	8.36	8.79	8.21	8.64	9.09	8.79	9.24	9.70
Box 3 (95%)	5.24	5.59	5.95	5.83	6.19	6.58	6.05	6.42	6.81
Table S1: Comparison of the annual average storm frequency (Lambda) in terms of VOR (hPa/(deg.lat^2)) ECHAM5 20C with A1B and A2 storm frequency including 90% CI estimates for each region of the North Atlantic (Boxes 1,2 and 3). Columns Lower and Upper denote the lower and upper bounds of the 90% CI respectively. Only Lambda for under A2 in Boxes 2 and 3 are significantly different at the 1% level from the corresponding 20C Lambda. Percentages in brackets in the left column indicate the threshold for the GPD.

