Taken as a whole (and using official figures), the average world inflation rate has risen to 5.5%, its highest since 1999. The main cause has been the surge in the prices of food and oil, which briefly soared above $135 a barrel this week. But Mr Trichet's concern is that higher headline rates could push up inflation expectations, leading to bigger pay demands, and so trigger a wage-price spiral, as in the 1970s. Central bankers' mistake then was to hold monetary policy too loose, so that higher oil prices quickly fed into other prices. So it is worrying that global monetary policy is now at its loosest since the 1970s: the average world real interest rate is negative.
By slashing interest rates as inflation has climbed, has the Fed sowed the seeds of a new inflationary era? That case looks hard to prove in the rich world. Inflation rates of 3.9% in America and 3.3% in the euro area are far higher than central banks want, and inflation expectations are rising. If growth in the euro area remains robust, the ECB should certainly worry more about inflation. Yet so far there is little sign that higher food and oil prices are pushing up other prices in the rich economies. Wages have remained relatively subdued and core rates of inflation (excluding food and energy) are little higher than a year ago. Moreover, growth is expected to be below trend in America and Europe over the next year or so and unemployment is likely to climb, which will help to curb wage rises. America's consumer-confidence index has fallen to a 28-year low, which suggests that consumer spending will fall. This, in turn, will spur firms to cut costs and limit pay rises.
The picture is very different in emerging countries. Prices are rising much faster partly because food accounts for a bigger chunk of their consumer-price indices. But wages (rising at nearly 30% a year in Russia) and core-inflation rates are also accelerating. Many of these economies are operating close to full capacity, where inflation is more likely to take hold.
There are alarming similarities between emerging economies today and the rich world in the 1970s when the Great Inflation lifted off. Many policymakers in emerging markets view the rise in inflation as a short-term supply shock and so see little need to raise interest rates. Instead they are using price controls and subsidies to cap prices. Money supplies are growing almost three times as fast as in the developed world. Many central banks are still not fully independent. And inflationary expectations are not properly anchored, increasing the risk of a wage-price spiral. Emerging markets may as well be inviting the muggers into their own homes.