This year has turned out to be a surprisingly good one for the world economy. Global output has probably risen by close to 5%, well above its trend rate and a lot faster than forecasters were expecting 12 months ago. … China’s economy has not suffered a hard landing. America’s mid-year slowdown did not become a double-dip recession. Granted, the troubles of the euro area’s peripheral economies have proved all too real. Yet the euro zone as a whole has grown at a decent rate for an ageing continent, thanks to oomph from Germany, the fastest-growing big rich economy in 2010. The question now is whether 2011 will follow the same pattern.