More than 200 economists and AI researchers, including 16 Nobel laureates, have signed an open letter calling on world leaders to immediately prepare for the economic consequences of artificial intelligence. Organised by Stanford University's Digital Economy Lab, the letter warns that AI could drive a transformation larger than the Industrial Revolution but occurring far more rapidly, potentially causing large-scale job displacement while also raising living standards. The signatories urge governments and industry to establish incentives, safeguards, and institutions before the disruption takes hold, cautioning that waiting for certainty before acting would mean arriving too late.