Tail risks. Can we afford right now to think about tail risks? Probably not: right now what were our tail risks have become head risks, and given them and our day jobs we are all fully absorbed.
But if we are going to be spending even a little time thinking about tail risks, the big worry has to be that something happens to cause the Global North to stop investing, as it did in 2008-2009.
Cast your minds back to ten years and two months ago. Back then people were patting themselves on the back; The United States had wound down from its over-the-top overcommitment to housing construction, and had done so without a recession. The Federal Reserve had handled the unpleasantness of mortage-firm, structured-product, and Bear-Stearns bankruptcy. In doing so the Federal Reserve had effectively guaranteed the unsecured debt of every systemically-important commercial and investment bank in and out of New York. The forecast—at least among those who were not close students of Hyman Minsky, an who had not paid attention to Paul Krugman's The Return of Depression Economics—was for at most a small recession, with the balance of risks such that the major risk to the economy—at least in the minds of the Federal Reserve's Open Market Committee—was an increase in core inflation.