The premises of this paper rely on associating policy inertia toward action on climate change with the inadequacy of the classical ‘liability culture’ of evidence-based policy-making to deal with this global environmental challenge. To provide support to this hypothesis, the following discussion analyses the technical properties and the current policy use of Integrated Assessment Modelling (IAM) of economic-climate interactions. The paper contends that IAM is still not clarified enough as far as its potential for information- production in the framework of policy making processes is concerned, and that this fact is symptomatic of the current inability of societies to undertake the challenge of sustainability. The paper explains the reasons for this disconnect and proposes solutions in the form of a renovated framework of deliberative policy-making.