Climate change can be viewed as a fundamentally economic problem: Emissions of greenhouse gases have no economic value, so they are freely overproduced, to the entire planet’s detriment. This lecture introduces to these problems. It first provides some information on the greenhouse effect and the impact of human activity on global warming. This lecture also introduces to the integrated assessment models which help to assess the effect of the emission of greenhouse gases on economic growth. Finally, it also introduces to the different policy tools