This paper offers a methodology that enables characterisation of the behaviour of water resources systems under the impact of climate change through assessment of sensitivity patterns in a wide range of hydrologic variations produced by such change. Analysis is based on the application of two indicators that, in turn, draw on the results of a system optimisation model. Under this methodology the potential sensitivity of water resources systems in the cases of different climate projections are visualised, allowing those systems that require special attention in their adaptation to climate change to be identified. The methodology is applied to three basins located in Spain: Guadalquivir, Ebro and the Spanish part of the international basin Duero. © 2013 Springer Science+Business Media Dordrecht.