Abstract: Japans carbon tax system has evolved gradually over the past half-century, passing through four distinct phases: the initial development and exploration of the system; institutional optimization in the context of fulfilling emission reduction commitments; the establishment and refinement of the “Global Warming Countermeasures Tax”; and the stable operation of the carbon tax system alongside policy coordination.Today, it has evolved into a comprehensive carbon pricing system centered on the carbon tax and integrated with a variety of emission reduction mechanisms.In terms of implementation outcomes, while Japans carbon tax has had limited emissions-reduction effects in the short term, through the continuous transmission of price signals, the system has exerted a structural guiding influence on energy structure transformation, corporate investment decisions, and consumer behavior in the medium to long term.Overall, Japans strategy of implementing the system incrementally has ensured its long-term acceptability and sustainable operation. However, this cautious approach also imposes limits on the systems implementation: with low tax rates and broad exemptions, the uniformity and effectiveness of carbon pricing are both weakened, making it difficult for the carbon tax alone to shoulder the burden of ambitious emission reduction targets, and resulting in emission reduction outcomes that are clearly “dependent” on other measures.Practical experience with Japans carbon tax system shows that a gradual implementation strategy helps stabilize market expectations and guide long-term investment; the carbon tax should be positioned as a foundational pricing tool rather than a standalone emissions reduction measure; and the long-term incentive effects of the carbon pricing mechanism depend on the synergy of multiple policy systems.

Key words: climate change, carbon tax, environmental tax system, Japan