Energy Policy Institute, University of Chicago, Chicago, IL, USA.
Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA, USA.
Nature. 2021 Oct;598(7880):308-314. doi: 10.1038/s41586-021-03883-8. Epub 2021 Oct 13.
Estimates of global economic damage caused by carbon dioxide (CO) emissions can inform climate policy. The social cost of carbon (SCC) quantifies these damages by characterizing how additional CO emissions today impact future economic outcomes through altering the climate. Previous estimates have suggested that large, warming-driven increases in energy expenditures could dominate the SCC, but they rely on models that are spatially coarse and not tightly linked to data. Here we show that the release of one ton of CO today is projected to reduce total future energy expenditures, with most estimates valued between -US$3 and -US$1, depending on discount rates. Our results are based on an architecture that integrates global data, econometrics and climate science to estimate local damages worldwide. Notably, we project that emerging economies in the tropics will dramatically increase electricity consumption owing to warming, which requires critical infrastructure planning. However, heating reductions in colder countries offset this increase globally. We estimate that 2099 annual global electricity consumption increases by about 4.5 exajoules (7 per cent of current global consumption) per one-degree-Celsius increase in global mean surface temperature (GMST), whereas direct consumption of other fuels declines by about 11.3 exajoules (7 per cent of current global consumption) per one-degree-Celsius increase in GMST. Our finding of net savings contradicts previous research, because global data indicate that many populations will remain too poor for most of the twenty-first century to substantially increase energy consumption in response to warming. Importantly, damage estimates would differ if poorer populations were given greater weight.
二氧化碳（CO）排放造成的全球经济损失估计可以为气候政策提供信息。碳的社会成本（SCC）通过描述今天额外的 CO 排放如何通过改变气候来影响未来的经济结果来量化这些损失。先前的估计表明，能源支出的大幅增加，因变暖而导致的增加可能会主导 SCC，但它们依赖于空间粗糙且与数据紧密联系的模型。在这里，我们表明，今天释放一吨 CO 预计将减少未来总能源支出，大多数估计值在-30 美元至-100 美元之间，具体取决于折扣率。我们的结果基于一种架构，该架构集成了全球数据、计量经济学和气候科学，以估算全球各地的本地损失。值得注意的是，我们预计由于变暖，热带新兴经济体的电力消耗将大幅增加，这需要进行关键基础设施规划。然而，较冷国家的供暖减少抵消了这种全球增长。我们估计，全球平均表面温度（GMST）每升高 1°C，2099 年全球年用电量将增加约 45 亿焦耳（占当前全球用电量的 7%），而其他燃料的直接消耗量将减少约 113 亿焦耳（占当前全球用电量的 7%）每升高 1°C GMST。我们发现净储蓄与先前的研究结果相矛盾，因为全球数据表明，在 21 世纪的大部分时间里，许多人口仍然太穷，无法为应对变暖而大幅增加能源消耗。重要的是，如果给予贫困人口更大的权重，损害估计将有所不同。
