Climate Risks and Carbon Prices: Revising the Social Cost of Carbon
Climate Risks and Carbon Prices: Revising the Social Cost of Carbon
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DOI：
10.5018/economics-ejournal.ja.2012-10
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发表时间：
2012-04-04
影响因子：
0.5
通讯作者：
Stanton, Elizabeth A.
中科院分区：
文献类型：
--
作者：
Ackerman, Frank;Stanton, Elizabeth A.
美国政府的一个工作组估计，2010年碳排放的社会成本（或额外一吨二氧化碳排放造成的边际损害）为21美元/吨CO（2）。然而，这种计算忽略了许多与气候变化相关的最大风险，并低估了当前排放对后代的影响。我们的再分析探讨了气候敏感性的不确定性，损害函数的形状和贴现率的影响。我们表明，碳的社会成本在很大范围内是不确定的，可能远高于21美元/吨CO（2）。在我们的情况下，结合高气候敏感性，高损害和低贴现率，碳的社会成本在2010年可能接近900美元/吨CO（2），上升到1美元，500/tCO（2）在2050年。尽可能快地消除二氧化碳排放的最雄心勃勃的情景（到本世纪末实现全球净排放量为零或负）需要在2050年之前为每吨二氧化碳减排支出高达150至500美元。因此，使用一套合理的替代假设，2050年排放一吨二氧化碳造成的损害可能超过以最大技术可行率减少排放的成本。一旦出现这种情况，碳的社会成本的确切价值就失去了重要性：明确的政策处方是尽快减少排放，成本效益分析比成本效益分析更能为气候政策提供更好的见解。
The social cost of carbon - or marginal damage caused by an additional ton of carbon dioxide emissions - has been estimated by a U.S. government working group at $21/tCO(2) in 2010. That calculation, however, omits many of the biggest risks associated with climate change, and downplays the impact of current emissions on future generations. Our reanalysis explores the effects of uncertainty about climate sensitivity, the shape of the damage function, and the discount rate. We show that the social cost of carbon is uncertain across a broad range, and could be much higher than $21/tCO(2). In our case combining high climate sensitivity, high damages, and a low discount rate, the social cost of carbon could be almost $900/tCO(2) in 2010, rising to $1,500/tCO(2) in 2050.The most ambitious scenarios for eliminating carbon dioxide emissions as rapidly as technologically feasible (reaching zero or negative net global emissions by the end of this century) require spending up to $150 to $500 per ton of reductions of carbon dioxide emissions by 2050. Using a reasonable set of alternative assumptions, therefore, the damages from a ton of carbon dioxide emissions in 2050 could exceed the cost of reducing emissions at the maximum technically feasible rate. Once this is the case, the exact value of the social cost of carbon loses importance: the clear policy prescription is to reduce emissions as rapidly as possible, and cost-effectiveness analysis offers better insights for climate policy than cost-benefit analysis.