期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2021
卷号：118
期号：46
DOI：10.1073/pnas.2104061118
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
Studies have shown that long-term damages from unmitigated climate change are greater than the mitigation costs worldwide, but costs greatly exceed climate benefits in the near term, undermining action now. Emissions reductions affect more than just climate, however. We show that near-term US benefits of decarbonization are dominated by improved air quality for human health, labor productivity, and agriculture whereas climate-related benefits are realized largely after 2050. Additionally, using recent health research, we show that health benefits of both clean air and reduced climate change are far larger than previously estimated. Considering these additional benefits of emissions reductions, benefits outweigh costs even in the near term. Near-term benefits stem primarily from US actions, whereas long-term climate-related benefits require global cooperation.
Societal benefits from climate change mitigation accrue via multiple pathways. We examine the US impacts of emission changes on several factors that are affected by both climate and air quality responses. Nationwide benefits through midcentury stem primarily from air quality improvements, which are realized rapidly, and include human health, labor productivity, and crop yield benefits. Benefits from reduced heat exposure become large around 2060, thereafter often dominating over those from improved air quality. Monetized benefits are in the tens of trillions of dollars for avoided deaths and tens of billions for labor productivity and crop yield increases and reduced hospital expenditures. Total monetized benefits this century are dominated by health and are much larger than in previous analyses due to improved understanding of the human health impacts of exposure to both heat and air pollution. Benefit–cost ratios are therefore much larger than in prior studies, especially those that neglected clean air benefits. Specifically, benefits from clean air exceed costs in the first decade, whereas benefits from climate alone exceed costs in the latter half of the century. Furthermore, monetized US benefits largely stem from US emissions reductions. Increased emphasis on the localized, near-term air quality–related impacts would better align policies with societal benefits and, by reducing the mismatch between perception of climate as a risk distant in space and time and the need for rapid action to mitigate long-term climate change, might help increase acceptance of mitigation policies.
关键词：climate change; air pollution; decarbonization; health impacts; labor impacts
