For the global economy, it was the best of times, and then it was the worst of times. Buoyed by very strong growth in emerging markets, the global economy boomed in the mid-2000s. On average, annualised world GDP growth exceeded 5% for the four years leading up to 2007 – a pace of growth that hadn’t been sustained since the early 1970s. But it wasn’t to last. In this post, I illustrate how the failure of Lehman Brothers in September 2008 coincided with the deepest, most synchronised global downturn since World War II. And I describe how after having seen the fallout of the Lehman collapse, macroeconomic forecasters were nevertheless surprised by the magnitude of the ensuing global recession.