Marginal abatement cost is a term used in climate change economics to refer to the costs of reducing greenhouse gas emissions. A number of synonyms exist for this term, including carbon price, emission cost, carbon cost, emission abatement cost, and carbon abatement cost. Each of these terms describes the same basic concept: the cost of reducing or avoiding emissions, either through the use of new technologies or through changes in behavior or policies. The exact definition of each term may vary slightly, but they are all used in the same context to describe the economic impact of climate change mitigation efforts.