America’s new normal temperature is a degree higher than it was just two decades ago.
Scientists have long talked about climate change – higher temperatures, changes in rain and snowfall and more extreme weather – being the “new normal”. Data released on Tuesday by the National Oceanic and Atmospheric Administration put concrete figures on the cliché.
The new US normal is not only warmer, but more humid in the eastern and central parts of the nation and considerably drier in the west than just a decade earlier.
Meteorologists calculate normal climates based on 30 years of data to limit random fluctuations in the daily climate. It is a standard set by the World Meteorological Organization. Every 10 years, NOAA normal updates for the country as a whole, states and cities – by year, month and season.
For the entire country, the normal annual temperature is now 53.3 degrees (11.8 degrees Celsius) based on data from the 1991 to 2020 weather station, almost half a degree warmer than a decade ago. Twenty years ago, the normal was 52.3 degrees (11.3 degrees Celsius) based on data from 1971 to 2000. The average US temperature for the 20th century was 52 degrees (11.1 degrees Celsius).
The new annual US normal temperature is 1.7 degrees (0.9 Celsius) hotter than the first normal calculated for 1901 to 1930.
“Almost everywhere in the U.S. has warmed from normal from 1981 to 2010 to normal from 1991 to 2020,” said Michael Palecki, NOAA’s normals project manager.
Fargo, North Dakota, where the new normal is a tenth of a degree colder than the old, is an exception, but more than 90% of the U.S. has higher normal temperatures now than 10 years ago, Palecki said.
In Chicago and Asheville, North Carolina, the new annual normal temperature jumped 1.5 degrees in a decade. Seattle, Atlanta, Boston and Phoenix have had their normal annual temperature rise by at least half a degree over the past decade.
Charlottesville, Virginia, saw the biggest jump in normal temperatures among the 739 major weather stations. Other major changes occurred in California, Texas, Virginia, Indiana, Arizona, Oregon, Arkansas, Maryland, Florida, North Carolina and Alaska.
New normals are hotter because burning fossil fuels is doing the last decade “A much warmer period of time for much of the globe than in previous decades,” said Cornell University climate scientist Natalie Mahowald.
For Phoenix, the biggest change in normal came in precipitation. The normal annual rainfall for Phoenix has dropped 10% to 7.2 inches (18.2 centimeters). Los Angeles rainfall fell 4.6%.
At the same time, Asheville saw an almost 9% increase in rainfall, while New York City rains increased by 6%. Seattle normal is 5% more humid than it used to be.
Climate scientists are divided over how useful or misleading the newly calculated normals are.
Mahowald and University of Oklahoma meteorology professor Jason Furtado said that updating normal calculations helps city and regional planners prepare for floods and droughts, farmers decide what and when to plant, energy companies to serve to the ever-changing demands and doctors to deal with public health problems arising from the changing climate.
But Pennsylvania State University climate scientist Michael Mann said he prefers a constant baseline, like 1951 to 1980, which is what NASA uses. Adjusting normal every 10 years “perverts the meaning of ‘normal’ and ‘normalizes’ climate change,” he said in an email.
North Carolina state climatologist Kathie Dello said, “It seems strange to still call them normal because 1991-2020 was anything but normal in terms of the weather.”
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