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A Flock of Black Swans

CAMBRIDGE – Throughout history, major political and economic shocks have often occurred in August, when leaders have gone on vacation believing that world affairs are quiet. Consider World War I’s outbreak in 1914, the Nazi-Soviet pact in 1939, the Sputnik launch in 1957, the Berlin Wall in 1961, and the failed coup in Moscow of 1991. Then there was the Nixon shock of 1971 (when the American president took the dollar off the gold standard and imposed wage, price, and trade controls), the 1982 international debt crisis in Mexico, the 1992 crisis in the European Exchange Rate Mechanism, and the 2007 subprime mortgage crisis in the United States.

Many of these shocks constituted events that had previously been considered unthinkable. They were not even on the radar screen. Such developments have been called “black swans” – events of inconceivably tiny probability.