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The framework for evaluating public investments and policies was developed long before the fight against climate change became a major issue. The purpose of this article is to show that through the lowering of the discount rate, the lengthening of the scenario horizon, and the rise in the value of carbon, it is now possible to make a good assessment of the climate impacts of projects. At the same time, the redistributive stakes of the fight against climate change are also increasingly well understood. Properly assessing the environmental, economic and social effects of the various actions envisaged upstream increases the chances of prioritising them and deploying them in the right order, while taking on board the inevitable uncertainties about the availability and costs of decarbonisation technologies. In short, while evaluation is not the strategy, it does provide tools for achieving the strategic objectives we set ourselves at the lowest economic and social cost.