Essays on the economics of climate change.

Summary This thesis addresses several diverse issues related to climate policy. The first chapter examines the optimal extraction of a polluting non-renewable resource in the presence of environmental regulation and when a clean technology can be developed through research and development activities. The second chapter studies the introduction of carbon capture and storage technology. Where technical constraints do not allow all emissions to be captured, this technology should be used before environmental damage occurs. The third chapter studies the changes in the optimal tax system when an externality is discovered, in a Mirlees-like framework with heterogeneous agents. If productivity and the cost of access to a substitute good are negatively correlated, then no good should be taxed in the absence of an externality. With externality, it is optimal to tax the dirty good at a rate lower than the piggyback rate and to tax the clean good. In the fourth chapter, we build, calibrate and simulate a stylized model designed to evaluate the magnitude of the carbon tax that would allow the French economy to divide its CO2 emissions by four over a forty year horizon. The magnitude of the required carbon tax is completely unrealistic. The fifth chapter discusses the ecological discount rate that should be used to evaluate projects to improve the environment. We study the properties of the standard discount rate, as well as the ecological discount rate. We also discuss a form of the precautionary principle.