Based on UN projections from the period 2015 to 2050, Rebekah Smith and Farah Hani have calculated that prime working-age populations of OECD countries?will shrink by more than 92 million people while there will be nearly 1.4 billion new working-age people in developing countries. This note updates and extends that analysis, including by examining the coming labor shortage In upper middle income countries, where the forecast decline in the number of workers is even larger than in high-income countries. Unaddressed, the global workforce imbalance is a threat to economic performance in both poorer and richer countries. But it also presents a considerable opportunity to both sets of countriesif they embrace global worker mobility