"Our beliefs about the non-linear, chaotic, multi-scale climate system tend not to fall easily into boxes labelled 'justified' and 'speculative'. Instead, beliefs about climate processes and their effects tend to fall along a spectrum were they may be more or less justified by reference to the available evidence and theory. This is important and argues for a shift in the way climate modellers work. It argues for a 'probabilistic turn' in which we seek to take uncertainty and degrees of beliefs seriously, where we can. This shift is quietly underway among the climate research community, as is evident from the increasing prominence given to probabilistic climate forecasting in conference agendas over the last five or six years. This may sounds a little irrelevant: I appreciate that worrying about the ontological status of claims about the climate system may seem like an academic’s typically pointy-headed, unhelpful response to a serious global threat, but in fact thinking carefully about the uncertainties surrounding our understanding of climate has some powerful real world implications".
Does this seem a little daunting? Don't worry: Dave's whole piece is easier than you may think, and well worth reading.
The same goes for this article from Ray Bradley, William Connolley, Michael Mann and Gavin Schmidt.