Commentary Shortly before her nomination as Treasury secretary in the Biden administration, Janet Yellen appeared on a Bloomberg New Economy panel discussing the role of central banks as the world struggles to emerge from the COVID-19 pandemic. The panel revealed a sharp difference of opinion between Yellen and one of her predecessors—Larry Summers, President Bill Clinton’s second Treasury secretary. “Don’t we think that central banks really need to be careful about holding out the idea that they are relevant to sectoral issues involving differentials between one sector or another like environmental protection?” Summers asked. The environment isn’t within central banks’ “proper remit,” Summers suggested; having the Fed make special efforts to buy green bonds was “a confusion.” “On sustainable goals, I think it does make sense for supervisors to be taking the risks from both climate-related risks and the risk of changes in prices and stranded assets,” Yellen replied, articulating what has …