Heat Waves and Climate Change

The document details how climate change is increasing the frequency and intensity of heat waves across the United States, leading to severe health risks and societal disruptions. It highlights the vulnerability of specific populations, such as the elderly and outdoor workers, and the role of the urban heat-island effect. The text argues that stabilizing carbon emissions and adhering to the Paris Agreement can significantly reduce the projected increase in extreme temperatures and the frequency of heat waves by mid-century.

• Heat stress conditions in the US have increased in recent decades; between 1949 and 2005, 20 percent of 187 studied weather stations saw a substantial rise in one-day extreme heat stress events, averaging 12 more such days per year in 2005 than in 1949.
• Future projections indicate that if carbon emissions continue to grow, most of the US could see 20 to 30 more days annually with maximum temperatures exceeding 90°F, with the Southeast potentially seeing 40 to 50 more days. By 2100, the hottest daily temperatures in the US could increase by at least 10°F compared to the end of the 20th century if emissions increase substantially.
• Extreme heat poses significant health risks, including heat cramps, heat exhaustion, and heat stroke (which occurs when body temperature exceeds 103°F), as well as increased cardiovascular and respiratory mortality. Vulnerable groups include the young, elderly, low-income residents, people with pre-existing medical conditions, and outdoor workers in construction and agriculture.
• Extreme heat disrupts various sectors: it lowers student performance (particularly for low-income and minority students lacking air conditioning), threatens the livelihoods of rural residents through negative effects on crop production and livestock, and damages infrastructure, as evidenced by flight cancellations in Phoenix in 2017 when temperatures hit 119°F.
• Mitigation strategies can limit future heat; stabilizing carbon emissions to keep atmospheric CO2 below 550 ppm by 2100 could reduce the frequency of mid-century heat waves by approximately 50%. Following the Paris Agreement goal of keeping warming below 3.6°F could limit the increase in the hottest daily temperatures to 3.6°F instead of 10°F.

APA

Union of Concerned Scientists (2018). Heat Waves and Climate Change. https://www.ucs.org/resources/heat-waves-and-climate-change

Chicago

Union of Concerned Scientists. Heat Waves and Climate Change. 2018. https://www.ucs.org/resources/heat-waves-and-climate-change.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Heat Waves and Climate Change |date=31 July 2018 |url=https://www.ucs.org/resources/heat-waves-and-climate-change |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2018heat, author = {{Union of Concerned Scientists}}, title = {{Heat Waves and Climate Change}}, institution = {Union of Concerned Scientists}, year = {2018}, month = jul, url = {https://www.ucs.org/resources/heat-waves-and-climate-change}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }