Valuing the Global Mortality Consequences of Climate Change Accounting for Adaptation Costs and Benefits
Quarterly Journal of Economics · 2022 · Tamma Carleton、Amir Jina、Michael Delgado、Michael Greenstone、Trevor Houser、Solomon Hsiang
中文摘要
利用40个国家的次国家层面数据，我们估计了分年龄的死亡率-温度关系，并将其外推至目前缺乏数据的国家以及气候变化下的未来情景。我们发现了一种U形关系：极端寒冷和炎热的温度都会提高死亡率，尤其是老年人的死亡率。至关重要的是，较高的收入以及对当地气候的适应会使这一关系趋于平缓。我们采用显示性偏好方法估算不可观测的适应成本，结果表明，在高排放情景下，计入适应收益与成本后，气候变化导致的全球平均死亡风险增量在2100年的估值约相当于全球GDP的3.2%。值得注意的是，预计目前寒冷的地区将从中受益，而目前贫困且炎热的地区预计将遭受巨大损失。最后，我们的核心估计表明，在高排放情景下，当前每额外排放一吨CO2将造成36.6美元的死亡相关损害；计入计量经济学与气候不确定性后，其四分位距为[−7.8美元，73.0美元]。这些以实证为基础的估计比既有文献中的估计高出一个数量级。
Abstract
Abstract Using 40 countries’ subnational data, we estimate age-specific mortality-temperature relationships and extrapolate them to countries without data today and into a future with climate change. We uncover a U-shaped relationship where extre6me cold and hot temperatures increase mortality rates, especially for the elderly. Critically, this relationship is flattened by higher incomes and adaptation to local climate. Using a revealed-preference approach to recover unobserved adaptation costs, we estimate that the mean global increase in mortality risk due to climate change, accounting for adaptation benefits and costs, is valued at roughly 3.2% of global GDP in 2100 under a high-emissions scenario. Notably, today’s cold locations are projected to benefit, while today’s poor and hot locations have large projected damages. Finally, our central estimates indicate that the release of an additional ton of CO2 today will cause mortality-related damages of $36.6 under a high-emissions scenario, with an interquartile range accounting for both econometric and climate uncertainty of [−$7.8, $73.0]. These empirically grounded estimates exceed the previous literature’s estimates by an order of magnitude.