Climate modelling for policy-making: how to represent freedom of choice and concern for future generations?

When modelling is conceived as a means to illuminate policy-making in the field of climate change, modellers tend increasingly towards integrated assessment models to catch interactions between natural and economic systems on both sides. Ultimately models should elicit 'projected equilibrium', when achievements match expectations. Should we support this tendency, or should we set moral limits for the sake of freedom of choice of all generations? How should we view adaptation to climate change in the context of intergenerational ethics? Taking the Stern review as a background, this paper suggests that the use of fully integrated models for policy-making meets ethical difficulties and is caught up in paradoxes. The more we consider a long-term future, the more modelling should be disentangled and split into separate scenarios. It is also suggested that the focus of modelling should not be on maximisation of per capita consumption, but on how ecological capacities and human capabilities can be maintained or developed over time.