The world economy started 2020 on a positive note, fresh from a Donald Trump tweet at the end of last year signalling the US president was about to sign a limited “phase one” trade deal with China. The agreement suggested that the year might escape 2019’s curse of ever rising trade tensions. If so, 2020 would be spared increasing political risks and uncertainty, with knock-on benefits for investment and trade in all continents. This view has buoyed financial markets so far this year. The MSCI index of global equities was up more than 3 per cent in the month to the end of the first week in January. Bond prices have reflected even more optimistic thinking. Compared with last autumn, US risk-free interest rates on government bonds no longer signal a recession looming ahead. Yet this market optimism has not yet convinced economists who specialise in looking at the underlying data: they neither expected a global recession this year, nor are they now much more positive about the outlook. Economic forecasts for 2020 suggest another weak year ahead with little to no improvement from that foreseen in the autumn. The World Bank expects, using prevailing exchange rates, global output to rise from a decade low of 2.4 per cent in 2019 to 2.5 per cent in 2020. Something better would require, “a sustained reduction in policy uncertainty”, according to Ceyla Pazarbasioglu, the vice-president in charge of equitable growth at the World Bank.