Kenneth Rogoff (of 'This Time is Different' fame) speaking in Davos: When asked what the biggest risks to global growth are: "Obviously, there are a variety of existenail political risks: Brexit, Shutdown, and populist movements across various countries of Europe. But the biggest and most concrete risk, and the one that the Europe and Asia are already feeling, is slowdown in China which, I believe, reflects long-term productivity factors and not simply a discretionary tightening of credit. Another risk -- though only a tail risk -- is if something drove up global real interest rates from their current extremely low levels. Withh evey low interest rates, most of the public and private debt buildup around the world are extremely manageable but if real rates went up significantly, there wre problems in many areas (corporate debt, emerging markets, Italy etc,)"