Climate projections: Past performance no guarantee of future skill?
Article first published online: 7 JUL 2009
Copyright 2009 by the American Geophysical Union.
Geophysical Research Letters
Volume 36, Issue 13, July 2009
How to Cite
2009), Climate projections: Past performance no guarantee of future skill? Geophys. Res. Lett., 36, L13704, doi:10.1029/2009GL038082., and (
- Issue published online: 7 JUL 2009
- Article first published online: 7 JUL 2009
- Manuscript Accepted: 8 JUN 2009
- Manuscript Revised: 28 MAY 2009
- Manuscript Received: 16 APR 2009
- climate model selection;
- model skill;
- multi-model ensemble
 The principle of selecting climate models based on their agreement with observations has been tested for surface temperature using 17 of the IPCC AR4 models. Those models simulating global mean, Siberian and European 20th Century surface temperature with a lower error than the total ensemble for one period on average do not do so for a subsequent period. Error in the ensemble mean decreases systematically with ensemble size, N, and for a random selection as approximately 1/Nα, where α lies between 0.6 and 1. This is larger than the exponent of a random sample (α = 0.5) and appears to be an indicator of systematic bias in the model simulations. There is no evidence that any subset of models delivers significant improvement in prediction accuracy compared to the total ensemble.