We face a global economic crisis. And no one knows what to do about it

Central banks rode to the rescue of nervous investors for years. But now they are raising rates just as the world economy spirals downwards

Back in February, plenty of investors were betting that the buildup of Russian troops on Ukraine's border was no more than an elaborate bluff.

The Russian and Ukrainian currencies appreciated in value as hedge funds and private equity firms, signalling their faith in some form of peace deal emerging, confidently bought roubles and the Ukrainian hryvnia.