Modelling complexity: the case of climate science

...Chaos is the future and beyond it is freedom confusion is next and next after that is the truth..1 …llud in his quoque te rebus cognoscere avemus, corpora cum deorsum rectum per inane feruntur ponderibus propriis, incerto tempore ferme incertisque locis spatio depellere paulum, tantum quod momen mutatum dicere possis. Quod nisi declinare solerent, omnia deorsum, imbris uti guttae, caderent per inane profundum, nec foret offensus natus nec plaga creata principiis: ita nil umquam natura creasset...2 We briefly review some of the scientific challenges and epistemological issues related to climate science. We discuss the formulation and testing of theories and numerical models, which, given the presence of unavoidable uncertainties in observational data, the non-repeatability of world-experiments, and the fact that relevant processes occur in a large variety of spatial and temporal scales, require a rather different approach than in other scientific contexts. A brief discussion of the intrinsic limitations of geo-engineering solutions to global warming is presented, and a framework of investigation based upon non-equilibrium thermodynamics is proposed. We also critically discuss recently proposed perspectives of development of climate science based purely upon massive use of supercomputer and centralized planning of scientific priorities