After a calm 2010s, in which interest rates hardly budged, inflation is putting central-bank officials to work. Indeed, policymakers have rarely been busier. In the first quarter of 2021, policy rates in a sample of 58 rich and emerging economies stood at an average of 2.6{9f99fe44fce1aa3c813d0a0ce4da2fbea8a5a58e9d85c4a2927dd8140cb676b5}. By the final quarter of 2022, this figure had reached 7.1{9f99fe44fce1aa3c813d0a0ce4da2fbea8a5a58e9d85c4a2927dd8140cb676b5}. Meanwhile, total debt in these countries hit a record $300trn, or 345{9f99fe44fce1aa3c813d0a0ce4da2fbea8a5a58e9d85c4a2927dd8140cb676b5} of their combined gdp, up from $255trn, or 320{9f99fe44fce1aa3c813d0a0ce4da2fbea8a5a58e9d85c4a2927dd8140cb676b5} of gdp, before the covid-19 pandemic. The more indebted the world becomes, the more sensitive it is to rate rises. To assess the combined effect of borrowing and higher rates, The Economist…