The global economy is not going to be calmer any time soon

The world economy is racked by inflation and struggling with growth. But the situation is perhaps best summed up by one datapoint: the number and variety of policy changes announced by central banks around the world this week.

The Federal Reserve made the punchiest move. Its officials now expect core inflation — a measure that excludes the most volatile items — to settle at 4.3 per cent this year. This is a key part of why it…