“……As we know, there are known knowns…….there are known unknowns……but there are also unknown unknowns……”.
While the language may be a bit tortured, Donald Rumsfeld’s 2002 observation about the possibility of WMDs (weapons of mass destruction) in Iraq makes an important point. Not all risks (or uncertainties) are the same. The really dangerous ones are in the ‘unknown’ category, or what Nassim Taleb called ‘the black swans’. The July 2015 issue of The Ambachtsheer Letter raises the question where climate change fits on the unknown/known risk scale. It seems to be rapidly moving from the unknown to the known end of the risk scale.