In late 2008, at a meeting with academics at the London School of Economics, Queen Elizabeth II asked why no one seemed to have anticipated the world’s worst financial crisis in the postwar period. The so-called Great Recession, which had begun in late 2008 and would run until mid-2009, was set off by the sudden collapse of sky-high prices for housing and other assets — something that is obvious in retrospect but that, nevertheless, no one seemed to see coming.

Are we about to make the same mistake? All too likely, yes. Certainly, the American economy is doing well, and emerging economies are picking up steam. But global asset prices are once again rising rapidly above their underlying value — in other words, they are in a bubble. Considering the virtual silence among economists about the danger they pose, one has to wonder whether in a year or two, when those bubbles eventually burst, the queen will not be asking the same sort of question.

This silence is all the more surprising considering how much more pervasive bubbles are today than they were 10 years ago. While in 2008 bubbles were largely confined to the American housing and credit markets, they are now to be found in almost every corner of the world economy.

As the former Federal Reserve chairman Alan Greenspan recently warned, years of highly unorthodox monetary policy by the world’s major central banks has created a global government bond bubble, with long-term interest rates plumbing historically low levels.