The world economy is enjoying a synchronised recovery. But it will prove unsustainable if investment does not pick up, especially in high-income economies. Debt mountains also threaten the recovery’s sustainability, as the OECD, the Paris-based group of mostly rich nations, argues in its latest Economic Outlook. This report is the swansong of Catherine Mann, who was an outstanding OECD chief economist. It suggests that relief is legitimate, but complacency definitely is not,

The OECD forecasts 3.6 per cent global growth this year, up from 3.1 per cent in 2016. Growth is forecast to reach 3.7 per cent in 2018, close to the 1990-2007 average. The only member of the Group of Seven big economies whose growth this year is not expected to be higher than in 2016 is the UK. China and India are setting the global pace. The OECD monitors 45 economies that generate 80 per cent of global output. Not one is forecast to contract in 2017, 2018 or 2019.

Yet we have reason to question the sustainability of this rate of growth. Throughout the G7, net investment rates are lower than before the financial crisis. The growth of labour productivity is forecast to improve somewhat, yet remain well below its average between 1995-2007. Above all, high indebtedness continues to menace the recovery.