Intensification of Hot Extremes Projected in the United States


New research published in Geophysical Research Letters indicates that substantial intensification of hot extremes could occur within the next 3 decades even if the 2°C global warming target currently being considered by policy makers is achieved. The study found that by the 2030s, continued increases in greenhouse gas concentrations could result in as many as nine occurrences per decade of the highest seasonal temperature of the second half of the 20th century, and as many as seven occurrences per decade of the longest heat wave of the second half of the 20th century. The study also found that the intensification of hot extremes was associated with a shift towards atmospheric and surface moisture conditions that are currently associated with hot, dry episodes. These findings highlight the possibility that constraining global warming to 2°C may not be sufficient to avoid dangerous climate change impacts. The paper has received recent media coverage, including an AP story that was widely replicated the week of July 5th (Washington Post, Chicago Tribune, LA Times, SF Chronicle, etc). It was also featured in two NY Times posts, one of which (Andy Revkin’s) was headlined on the front page of the NYT website, and was the lead story on Huffington Post this week, July 13th. The Principal Investigator, Diffenbaugh, was scheduled to be on NPR’s On Point show for an hour live on Thursday, July 15th.


Diffenbaugh, N. S., and M. Ashfaq. 2010. “Intensification of Hot Extremes in the United States,” Geophysical Research Letters 37 L15701. DOI: 10.1029/2010GL043888.