Dynamic games related to climate change.

Summary The thesis is devoted to the study of dynamic games in the climate domain. To fight against the accumulation of greenhouse gases in the atmosphere, the implementation of a carbon tax is a possible solution. However, it is assumed here that this carbon tax has motivations for fossil energy consuming countries that are not limited to the internalization of environmental damage: it is a strategic behavior to try to capture part of the producers' rent. This leads to the possibility of a carbon tax with a Pigouvian but also strategic purpose. Non-cooperative dynamic games between supposedly cartelized producer countries and supposedly cartelized consumer countries can then be envisaged in this context. A literature on non-cooperative differential games has been developed over the last twenty years around the idea of a carbon tax with a strategic aim. In the introduction, we recall the economic framework of these games, their analytical framework (differential games) and the related theoretical literature. We present three games that form the body of the thesis. Each of the following three chapters is devoted to an original differential game. The first game is a non-cooperative game between a block of consumers and a block of producers with a pollution cap as the main environmental constraint. The existence of this ceiling changes the classical conclusions of this type of game. In the second game, there is also a non-cooperative game between a block of consumers (rich countries) and a block of producers, but there is also a second block of consumers (poor and emerging countries), which does not play in the game but implements the carbon tax resulting at each moment of the game in return for a transfer from the first block of consumers. It appears that under certain conditions the second block has an interest in this "carbon tax versus transfer" scheme. In the third game, there are also two consumption zones, but they are now playing a non-cooperative game with each other, the producers being passive. There is a carbon tax per block and not a global one and yet the game shows under certain conditions a better situation for the consumption blocks than a passive situation towards the producers. The overall conclusion of these three games is that, under certain conditions, the consumer countries may have an interest in strategic and not just Pigouvian behavior with respect to carbon taxes.