Many countries face a long period of adjustment to erase the legacies of the crisis, particularly high unemployment, excess capacity and large fiscal imbalances. Further ahead, demographic changes, including ageing, and fundamental forces of economic convergence will bring about massive shifts in the composition of global GDP. To illustrate the nature and scale of some of the policy challenges posed by these developments, this chapter describes medium and long-term scenarios for OECD and non-OECD G20 countries using a new modelling framework to extend the short-term projections described in  . This framework focuses on the interaction between technological progress, demographic change, fiscal adjustment, current account imbalances and structural policies. The scenarios suggest that gradual but ambitious fiscal consolidation and structural reforms could bring about substantial gains in growth as well as reducing a range of risks, particularly by reducing large fiscal and current account imbalances.