In 2008 central banks, led by the Federal Reserve, rode to the rescue of the global financial system. A report by the Group of Thirty, an international body led by former European Central Bank chief Jean-Claude Trichet, warned on Saturday that zero rates and money printing were not sufficient to revive economic growth and risked becoming semi-permanent measures. “Central banks have described their actions as ‘buying time’ for governments to finally resolve the crisis… But time is wearing on, and (bond) purchases have had their price,” the report said.