Connecting Extreme Weather to Climate Change

The document outlines the development of 'climate attribution' science, which allows researchers to quantify the role of human-caused climate change in extreme weather. It identifies that evidence is strongest for heat waves, coastal flooding, and extreme precipitation, while remaining less conclusive for tornadoes and thunderstorms. The text provides specific examples of US events, such as Hurricane Harvey and the February 2017 heat wave, where climate change significantly increased likelihood or intensity.

• The field of 'climate attribution' has advanced to the point where scientists can now identify and quantify the specific role human-driven climate change plays in the frequency and intensity of many extreme weather events, moving beyond the previous blanket statement that no single event could be attributed to climate change.
• Scientific evidence for the link to climate change varies by event type: it is strongest for extreme heat waves, coastal flooding (from storm surge and high-tide events), and extreme precipitation, including hurricane downpours. Evidence is currently weaker or still growing for tornadoes, thunderstorms, and certain types of droughts.
• In the western United States, human-caused climate change—specifically warming temperatures and drying soils—has increased wildfire activity, including the number of large fires, area burned, and season length. However, other factors like land use and fire suppression also contribute, though climate change is the dominant driver in high-elevation forests with minimal human activity.
• Climate change often increases the intensity of events that might have occurred regardless; some recent record-breaking heat events are described as nearly or entirely impossible without human influence on the climate system.
• Specific US weather events have been linked to climate change: Hurricane Harvey's rainfall in Houston was roughly three times more likely and 15 percent more intense; the February 2017 contiguous US heat wave was more than three times more likely; and the August 2016 Louisiana rain event was at least 40 percent more likely.
• Human-caused sea level rise of eight inches since 1880 resulted in Hurricane Sandy's storm surge flooding an area approximately 27 square miles larger than it would have otherwise.

APA

Union of Concerned Scientists (2018). Connecting Extreme Weather to Climate Change. https://www.ucs.org/sites/default/files/attach/2018/06/The-Science-Connecting-Extreme-Weather-to-Climate-Change.pdf

Chicago

Union of Concerned Scientists. Connecting Extreme Weather to Climate Change. 2018. https://www.ucs.org/sites/default/files/attach/2018/06/The-Science-Connecting-Extreme-Weather-to-Climate-Change.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Connecting Extreme Weather to Climate Change |date=June 2018 |url=https://www.ucs.org/sites/default/files/attach/2018/06/The-Science-Connecting-Extreme-Weather-to-Climate-Change.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2018connecting, author = {{Union of Concerned Scientists}}, title = {{Connecting Extreme Weather to Climate Change}}, institution = {Union of Concerned Scientists}, year = {2018}, month = jun, url = {https://www.ucs.org/sites/default/files/attach/2018/06/The-Science-Connecting-Extreme-Weather-to-Climate-Change.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }