Emissions taxes impose a fixed price on emissions, whereas under tradable permit schemes prices emerge in the secondary permit market. The delayed price discovery under tradable permits creates uncertainty about the future cost of compliance that liable emitters face. To mitigate this uncertainty, some jurisdictions have designed policies to regulate GHG with an emissions tax that is in force for several years, subsequently transforming into a tradable permit scheme. This paper examines the effects that this staged transition – from no regulation to a regulation by a tax, to a regulation by tradable permits – has on abatement investment, quantity of emissions, permit prices and overall regulation efficiency. The effects of the inter-temporal mix of policy instruments are compared to the effects of single policy instrument: a tax-only, and a tradable permit-only regulation. Our investigation relied on laboratory economics methods to test economic behaviour under these three policy regimes. We find that a staged transition from a tax to a tradable permit scheme results in more socially desirable outcomes on a range of criteria when compared to a regulation based solely on tradable permits, and specifically, it improves ability to make better abatement investment decisions.

中文翻译：

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通过跨期政策组合调控温室气体排放：一项实验性调查*

排放税对排放征收固定价格，而在可交易许可计划下，价格出现在二级许可市场。可交易许可证下的延迟价格发现给负责任的排放者面临的未来合规成本带来了不确定性。为减轻这种不确定性，一些司法管辖区制定了政策，通过实施多年的排放税来规范温室气体，随后转变为可交易的许可计划。本文研究了这一阶段性过渡——从无监管到税收监管，再到通过可交易许可证监管——对减排投资、排放量、许可证价格和整体监管效率的影响。将跨期政策工具组合的影响与单一政策工具的影响进行比较：仅税收，和可交易的仅限许可证的规定。我们的调查依赖于实验室经济学方法来测试这三种政策制度下的经济行为。我们发现，与仅基于可交易许可的法规相比，从税收到可交易许可计划的分阶段过渡会在一系列标准上产生更符合社会期望的结果，具体而言，它提高了做出更好的减排投资决策的能力。