Intensification of hot extremes in the United States

This was an unprecedented experiment. With the high-resolution climate model, we can analyze geographic quadrants that are only 15.5 miles [25 kilometers] to a side. No one has ever completed this kind of climate analysis at such a high resolution.

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Frankly, I was expecting that we'd see large temperature increases later this century with higher greenhouse gas levels and global warming. I did not expect to see anything this large within the next three decades. This was definitely a surprise.

Noah Diffenbaugh, co-author

• Uses a large suite of climate model experiments and finds that substantial intensification of hot extremes could occur within the next 3 decades, below the 2°C global warming target currently being considered by policy makers
• Finds that the intensification of hot extremes is associated with a shift towards more anticyclonic atmospheric circulation during the warm season, along with warm-season drying over much of the U.S.
• Finds the possibility that intensification of hot extremes could result from relatively small increases in greenhouse gas concentrations suggests that constraining global warming to 2°C may not be sufficient to avoid dangerous climate change