Department of Mechanical Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
Department of Civil and Environmental Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
Environ Sci Technol. 2017 Oct 3;51(19):10932-10942. doi: 10.1021/acs.est.7b01295. Epub 2017 Sep 25.
Using a least-cost optimization framework, it is shown that unless emissions reductions beyond those already in place begin at the latest by 2025 (±2 years) for the U.S. automotive sector, and by 2026 (-3 years) for the U.S. electric sector, 2050 targets to achieve necessary within-sector preventative CO emissions reductions of 70% or more relative to 2010 will be infeasible. The analysis finds no evidence to justify delaying climate action in the name of reducing technological costs. Even without considering social and environmental damage costs, delaying aggressive climate action does not reduce CO abatement costs even under the most optimistic trajectories for improvements in fuel efficiencies, demand, and technology costs in the U.S. auto and electric sectors. In fact, the abatement cost for both sectors is found to increase sharply with every year of delay beyond 2020. When further considering reasonable limits to technology turnover, retirements, and new capacity additions, these costs would be higher, and the feasible time frame for initiating successful climate action on the 70% by 2050 target would be shorter, perhaps having passed already. The analysis also reveals that optimistic business-as-usual scenarios in the U.S. will, conservatively, release 79-108 billion metric tons of CO. This could represent up to 13% of humanity's remaining carbon budget through 2050.
采用最低成本优化框架，结果表明，除非美国汽车行业最迟在 2025 年（±2 年）、美国电力行业最迟在 2026 年（-3 年）开始实施超出当前减排水平的减排措施，否则到 2050 年实现相对于 2010 年 70%以上的部门内预防性 CO 减排目标将是不可行的。分析结果没有发现任何证据表明，为了降低技术成本，可以推迟采取气候行动。即使不考虑社会和环境损害成本，在考虑到美国汽车和电力行业提高燃油效率、需求和技术成本的最乐观轨迹的情况下，推迟采取积极的气候行动也不会降低 CO 减排成本。事实上，这两个部门的减排成本都会随着 2020 年以后每年的延迟而急剧增加。当进一步考虑技术更替、退役和新增产能的合理限制时，这些成本将会更高，而在 2050 年实现 70%减排目标的成功气候行动的可行时间框架将会更短，也许已经过去了。分析还表明，美国乐观的按部就班情景将保守地释放 790-1080 亿吨 CO。这可能占人类到 2050 年剩余碳预算的 13%。
