FRANKFURT—Supply constraints thwarting global economic growth could still get worse, keeping inflation elevated longer, even if the current spike in prices is still likely to remain temporary, the world’s top central bankers warned on Wednesday. The disruptions to the global economy during the pandemic have upset supply chains across continents, leaving the world short of a plethora of goods and services from car parts and microchips to container vessels that transport goods across the seas. “It’s … frustrating to see the bottlenecks and supply chain problems not getting better, in fact at the margin apparently getting a little bit worse,” Federal Reserve Chair Jerome Powell told a conference. “We see that continuing into next year probably and holding inflation up longer than we had thought,” Powell told the European Central Bank’s (ECB) Forum on Central Banking. Speaking alongside Powell, ECB chief Christine Lagarde voiced similar concerns, arguing that the end …