Sergey Paltsev
Managing Uncertainty While Developing Long-Term Strategies for GHG Emission Mitigation
联合国巴黎一致性已经建立了一个目标，即相对于工业前水平，将全球平均表面温度升高至2°C低于2°C，并采取努力将温度升高到1.5°C。随着温室气体（GHG）在全球范围内继续上升（LeQuéré等人，2018年），到达目标是必要的。根据《巴黎协定程序》，每个参与国家都必须提交全国确定的捐款，这代表了每个国家在2025 - 30年之前减少温室气体排放的努力。但是，这些认捐的减少和将全球变暖限制在2100以下的2°C以下所需的减少之间存在很大差异（UNEP 2017）。根据《巴黎协定》，这些国家还被邀请传达其“本世纪中叶，长期的低温温室气体排放开发策略”（UNFCCC 2018）。鉴于排放差距，决策者总是必须准备更雄心勃勃的计划来加强温室气体缓解措施。
尽管所有政府或工业领导人都面临影响其决策过程的不确定性，包括对低碳技术选择的未来成本的不确定性，其他经济参与者的缓解行动的幅度以及经济增长的速度，但一件事是确定的。- GHG排放必须减少更多。今天迁移到低碳或无碳能力将减少将来减少温室气体排放的任务。
有人认为，不确定性证明了“等待行动”策略是合理的。也许我们应该拭目以待，看看气候影响是否确实像一些研究人员所描述的那样糟糕必威官网是真的吗？也许我们应该拭目以待，看看新技术是否会以更便宜的方式减少排放？但是，随着全球排放量的增长，等待采取行动不是一个好选择，因为它增加了必要的缓解行动的成本，因为必须最终减少大量排放。将不确定性作为风险问题更具生产力，因为随后的决策者需要为不良结果做好准备。行业领导人和政府决策者在应对风险方面拥有多年的经验。风险管理是一种良好的做法，可以识别和分析潜在风险，并采取预防措施以最大程度地减少它们。
我们在马萨诸塞州科技研究所关于全球变化的科学与政策的研究表明，即使是减少温室气体排放的行动，甚至有限的行动会大大降低了超过一定温度阈值的风险（Bosetti等人，2012年）。即使我们无法精确地预测气候及其影响，尤其是在区域和地方层面上必威官网是真的吗，这并不意味着最好的策略就是什么都不做。世界已经在解决气候变化方面取得了进展：尤其是，在促进可再生能源并降低可再生能源成本的政策方面取得了巨大进展。必威官网是真的吗但是，在与传统能源竞争的低碳能源方面仍然存在许多挑战。
Policy frameworks are the key to determining a nation’s ability to incentivize the deployment of new technologies, attract private capital, internalize externalities (such as the health effects of air pollution), modernize electricity transmission and distribution, and expand access to energy. These policy frameworks should combine肯定关于政策目标，以确保经济参与者的稳定投资环境和flexibility调整政策参数以优化系统的性能，以便以最低的成本实现政策目标。
A good way to manage uncertainty while developing a long-term strategy is to establish a clear and transparent policy mix that allows for periodic policy review and adjustments. In many cases, pilot programs (one or two years) can help fine-tune policy design and prepare economic actors for policy compliance; thereafter, however, policies with longer time horizons (five years or more) are recommended to provide planning and investment certainty to market participants. These medium-term policies should contribute to overarching long-term mitigation strategies and should be accompanied by robust planning processes to ensure consistency across instruments as well as to establish the supporting institutional and regulatory frameworks.
根据行政和技术能力和可用的政治支持，决策者应寻求方法来引入最有效的政策工具，以使缓解行动有灵活性。通过具有可交易单位的税收或数量控制的碳定价都将资源分配给市场，从而可以在所有被覆盖的实体中均衡减排成本，从而避免采摘技术，并提供优于替代工具的卓越成本效益。其他类型的工具（例如通过标准或补贴技术支持）可以成功建立支持联盟。
At a later stage, however, such targeted support measures should be reviewed and, where political will and institutional capacities allow, gradually phased out as more cost-effective mitigation instruments, such as carbon pricing, are introduced and scaled up. In any scenario, a crucial way to manage uncertainty and attract clean energy investment is to ensure property rights, contracts, and transparent dispute settlement procedures to guarantee the rights of investors.
Fragmented government structures with nonintegrated objectives have been identified as barriers to effective translation of national commitments to the regional and local level and to industrial actors (see, e.g., Resosudarmo et al. 2013 for the case of Indonesia). In many cases, different departments and ministries within a government have different objectives and priorities. To reduce uncertainty in future policies, integration and mainstreaming of climate policy priorities across all levels of the government is recommended. Any policymaking deals with multiple objectives, so coordinated policies must be created that address multiple objectives.
Developing a robust strategy to mitigate climate change can help achieve other objectives. Long-term planning should seek synergies in strategies to achieve multiple objectives. However, combining policy instruments can lower overall efficiency due to adverse interactions and trade-offs (Fischer and Preonas 2010; Paltsev et al. 2015). The experience of the European Union Emissions Trading System (EU ETS) provides an example where simultaneous operation of the trading system alongside targeted instruments to promote energy efficiency improvements and renewable energy deployment contributed to a severe imbalance of supply and demand in the carbon market, resulting in a prolonged collapse of allowance prices and a carbon price signal that has been too weak to promote fuel switching.
Policymakers should seek to integrate the objectives of different government and industrial entities with a policy package with one clear policy instrument. For example, a carbon tax designed in the Canadian province of British Columbia decreased carbon emissions, increased real GDP, reduced reliance on fossil fuel use, reduced personal income tax rates and general corporate income tax rates, and provided other tax benefits for businesses and consumers (Murray and Rivers 2015). Complimentary instruments that share a common objective with the core instrument can be employed to establish broader policy support.
The need for low-emitting technologies will shift the current technology mix, but the exact contribution of a particular technology and the timing of this shift depend on many economic and political variables. Such uncertainty about future costs and technologies should discourage governments from trying to pick the “winners”; instead, their policy and investment focus should be on targeting emissions reductions from any energy source (Paltsev 2017).
不确定性（在气候影响，政策和技术必威官网是真的吗中）不能完全消除，但这并不能证明“什么都不做”或“小”政策的论点是合理的。相反，缓解和适应活动的增加减少了一个国家的风险。决策者可以通过提供政策目标的确定性来减少整体不确定性。为低碳未来创造有吸引力的投资环境的一种强大方法是采用简单而透明的工具，激励演员以具有成本效益的方必威官网是真的吗式减少所有来源的排放。使经济范围的碳定价成为缓解策略的中心支柱，是一种透明，有效的工具，可实现更雄心勃勃的温室气体排放减少。成功的策略建立了短期可实现的目标（以在经济行为者对政策长寿之间建立信任）和长期最终目标的结合，同时确保灵活地实现目标。在许多情况下，政策制定者可以使用短时间框架制定试点计划，这些计划可以帮助您调整政策设计并为经济参与者做好准备以符合政策的合规性。此后，时间范围较长的政策可以提供计划和投资确定性。总体长期缓解战略应确保政策工具之间的一致性，并整合不同政府和工业参与者的目标。
参考
Bosetti，V.，S。Paltsev，J。Reilly和C. Carraro。2012年。“稳定全球气候的排放定价。”必威官网是真的吗在减轻气候变化的财政政策：政策制定者指南必威官网是真的吗，由R. de Mooij，I。Parry和M. Keen编辑，49-67。华盛顿特区：国际货币基金。
Fischer，C。和L. preonas。2010年。“结合可再生能源的政策：整体是否小于其部分的总和？”国际环境和资源经济学评论4: 51–92.
LeQuéré，C。，R。Andrew，P。Friedlingstein等。2018年。“ 2017年全球碳预算”。地球系统科学数据10：405–48。
Murray, B., and N. Rivers. 2015. “British Columbia’s Revenue-Neutral Carbon Tax: A Review of the Latest ‘Grand Experiment’ in Environmental Policy.”能源政策86：674–83。
Paltsev，S.，2017年。“能源方案：场景分析的价值和限制。”电线能量和环境6：E242。
Paltsev, S., V. Karplus, H. Chen, I. Karkatsouli, J. Reilly, and H. Jacoby. 2015. “Regulatory Control of Vehicle and Power Plant Emissions: How Effective and at What Cost?”必威官网是真的吗气候政策15：438–57。
Resosudarmo，B.P.，F。Ardiansyah和L. Napitupulu。2013。印度尼西亚气候变化治理的动态：发必威官网是真的吗展中国家的气候治理必威官网亚洲体育。Cambridge, UK: Polity.
UNEP（联合国环境计划）。2017。排放差距报告。https://www.unenvironment.org/resources/emissions-gap-report。
UNFCCC（联合国气候变化框架公约）。必威官网是真的吗2018年。“长期战略的交流”。https://unfccc.int/process/the-paris-agreement/long-term-strategies。
