Increasing mitigation ambition to meet the Paris Agreement's temperature goal avoids substantial heat-related mortality in U.S. cities

• Published in: Science advances 2019-06, Vol.5 (6), p.eaau4373
• Main Authors: Lo, Y T Eunice, Mitchell, Daniel M, Gasparrini, Antonio, Vicedo-Cabrera, Ana M, Ebi, Kristie L, Frumhoff, Peter C, Millar, Richard J, Roberts, William, Sera, Francesco, Sparrow, Sarah, Uhe, Peter, Williams, Gethin
• Format: Article
• Language: English
• Subjects: Atmospheric Science; Cities; Climate Change; Environmental Sciences; Epidemiology; Global Warming; Greenhouse Gases - analysis; Heat Stress Disorders - etiology; Heat Stress Disorders - mortality; Hot Temperature - adverse effects; Humans; Models, Theoretical; SciAdv r-articles; United States
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aau4373

Current greenhouse gas mitigation ambition is consistent with ~3°C global mean warming above preindustrial levels. There is a clear need to strengthen mitigation ambition to stabilize the climate at the Paris Agreement goal of warming of less than 2°C. We specify the differences in city-level heat-related mortality between the 3°C trajectory and warming of 2° and 1.5°C. Focusing on 15 U.S. cities where reliable climate and health data are available, we show that ratcheting up mitigation ambition to achieve the 2°C threshold could avoid between 70 and 1980 annual heat-related deaths per city during extreme events (30-year return period). Achieving the 1.5°C threshold could avoid between 110 and 2720 annual heat-related deaths. Population changes and adaptation investments would alter these numbers. Our results provide compelling evidence for the heat-related health benefits of limiting global warming to 1.5°C in the United States.