Pattern scaled climate change scenarios: are these useful for adaptation?

Pattern scaling methods are being widely applied to generate scenarios of climate change for quantification of their impacts on different systems. While generic limitations of this approach are welldocumented, the implications of the use of pattern scaling to inform adaptation decisions are not always made clear. The range of errors that are expected a priori are discussed and illustrated. Particular examples are used to demonstrate the extent to which pattern scaling is likely to be an unreliable tool for the quantification of the likely impacts of climate change. It is suggested that internal consistency tests are considered in any attempt to apply pattern scaling in practice.