Heat Waves and Climate Change

The document details the rising trends of heat waves and heat stress in the US, attributing recent increases to human-caused climate change and projecting more severe events by 2100 unless emissions are stabilized.

• The United States has seen an increase in the frequency and intensity of heat waves over the last several decades, with the Southeast experiencing the largest increase in the frequency of heat wave days since the late 1970s.
• Since the late 1970s, the number of days with record high temperatures in the US has increased, and there have been more record-breaking hot days than record-breaking cold days.
• The area of the US experiencing unusually hot summer nights is increasing at a faster rate than the area experiencing unusually hot summer days.
• Human-caused climate change has been linked to recent extreme heat; for example, the risk of the spring heat during the 2012 US heat wave was likely increased 12-fold, and the July 2012 extreme heat was four times more likely due to human activity.
• By mid-century, most of the US could see 20 to 30 more days per year with maximum temperatures exceeding 90°F if carbon emissions increase considerably, with the Southeast potentially seeing 40 to 50 more such days.
• Stabilizing global carbon emissions to keep atmospheric carbon dioxide below 550 parts per million by 2100 could reduce the frequency of mid-century US heat waves by approximately 50% compared to a high-emissions scenario (RCP8.5).
• By 2100, the hottest daily temperatures in the US are projected to increase by at least 10°F under high-emissions scenarios, but this increase could be limited to approximately 3.6°F if the Paris Agreement goal of keeping global warming below 3.6°F is met.

APA

Union of Concerned Scientists (2018). Heat Waves and Climate Change. https://www.ucsusa.org/sites/default/files/attach/2018/08/extreme-heat-science-fact-sheet.pdf

Chicago

Union of Concerned Scientists. Heat Waves and Climate Change. 2018. https://www.ucsusa.org/sites/default/files/attach/2018/08/extreme-heat-science-fact-sheet.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Heat Waves and Climate Change |date=August 2018 |url=https://www.ucsusa.org/sites/default/files/attach/2018/08/extreme-heat-science-fact-sheet.pdf |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 = aug, url = {https://www.ucsusa.org/sites/default/files/attach/2018/08/extreme-heat-science-fact-sheet.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }