Pandemics, global warming, food security, ageing, depletion of certain raw materials... our economies are faced with global problems, calling for long term actions and raising intergenerational issues. To guide economic policies, it is therefore essential to have a sound framework for reflection. The MaGE (Macroeconometrics of the Global Economy) model, developed by CEPII, makes it possible to draw the fundamental trends of the world economy in the long term, up to 2050. Assuming that the current dynamics of growth and technological catch-up will continue, and taking into account demographic dynamics, the balance of economic power will be strongly transformed over the next generation. Above all, energy consumption is expected to continue to grow at a sustained rate, and even double, despite efforts to improve energy efficiency. Ambitious policies to decarbonize our economies will be necessary to make these prospects for economic growth sustainable.