Theoretical and Empirical Study on Allocation of Costs relevant to Climate Change: Towards a Fair and Effective Climate Regime

在分配与气候变化有关的成本时，区分三种类型的成本是有益的，即(1)缓解成本、(2)适应成本和(3)气候损害成本。就减排成本而言，日本目前的政策以及2020年前的国际机制都是以支付意愿为基础的。减缓费用的分配方式应能有效地减少全球排放。市场机制可能有助于实现这种配置。对于适应成本和气候破坏成本，无论是在日本的政策中还是在国际制度中都没有明确的分配规则。由于这些费用来自过去排放的不利影响，使用“历史贡献”作为分配这些费用的标准是合理的。

When it comes to allocation of costs relevant to climate change, it would be useful to distinguish three types of costs, namely (1)mitigation cost, (2)adaptation cost, and (3)cost of climate damage. In terms of mitigation cost, current Japanese policy as well as international regime up to 2020 are both based on willingness to pay. The cost of mitigation should be allocated in way that produces a efficient and effective reduction of global emissions. The market mechanisms may help to realize such allocation. In terms of adaptation cost and cost of climate damage, there’re no clear rules on their allocation either in Japanese policy or in international regime so far. Since these costs derive from adverse impacts of the past emissions, it would be reasonable to use “historical contribution” as criteria for allocation of these costs.