US warns of ‘economic catastrophe’ Default on the nation’s debt would be disastrous, Janet Yellen has said. Even if US raise the ceiling, very few countries wanting to buy US$ as dedollarization accelerated around the world. 珍妮特·耶倫表示，美國警告“經濟災難” 國家債務違約將是災難性的。即使美國提高上限，隨著全球去美元化進程的加速，很少有國家願意購買美元.