“WASHINGTON — The official calculation of what constitutes “normal” U.S. climate has been updated — and to virtually nobody’s surprise, it’s a warmer picture than ever before.
“On Tuesday, the National Oceanic and Atmospheric Administration released an updated set of climate averages for the contiguous United States based on the 30-year period from 1991 to 2020, including more than 9,000 daily reporting stations. It refers to these averages as “climate normals,” and updates them once every decade.
“Compared to previous 30-year periods, the climate has turned unambiguously warmer.
“We’re really seeing the fingerprints of climate change in the new normals,” Michael Palecki, manager of NOAA’s effort to update the climate normals, said at an April news conference. “We’re not trying to hide that, we’re in fact reflecting that.”
The 30-year average temperature for the 48 contiguous states climbed to a record high of 53.28 degrees in the most recent 30 years, Palecki confirmed in an email.
Since 1901-1930, the first period for which climate normals were calculated, the contiguous U.S. has warmed 1.7 degrees, or just a little over 1 degree Celsius. That’s roughly on par with the global rate of warming over that period, although the United States was lagging the rest of the world until the last several decades.
The U.S. has seen its two largest jumps in temperatures during the two most recent 30-year periods for climate normals. They rose 0.5 degrees from the period 1971-2000 to 1981-2010 and 0.46 degrees from 1981-2010 to 1991-2020. Since 1901-1930, all but two of the 30-year periods have shown an increase in temperature.
“You can see that there’s a huge difference in temperature over time as we go from cooler climates in the early part of the 20th century to ubiquitously warmer climates here in the last two sets of normals,” Palecki said…”