For the record, it’s hotter
Over the past 20 years, Americans have been twice as likely to sweat through record-breaking heat rather than shiver through record-setting cold, a new Associated Press data analysis shows.
The AP looked at 424 weather stations throughout the Lower 48 states that had consistent temperature records since 1920 and counted how many times daily hightemperature records were tied or broken and how many daily low records were set. In a stable climate, the numbers should be roughly equal.
Since 1999, the ratio has been two warm records set or broken for every cold one nationally. And in 16 of the past 20 years, there have been more daily high-temperature records than low.
“We are in a period of sustained and significant warming and — over the long run — will continue to explore and break the warm end of the spectrum much more than the cold end,” said Deke Arndt, climate-monitoring chief at the National Oceanic and Atmospheric Administration.
The Dispatch used data from 12 Ohio weather stations to examine warming trends throughout the state.
Since 1999, the ratio for Ohio has been 1.16 warm records set or broken for every cold one, compared with 0.71 warm records set or broken for every cold one for the previous two decades (1979 to 1998). That’s a 63.4 percent increase.
“The ratio is a little bit smaller for record highs to record lows in Ohio and the Midwest and has to do with the water vapor,” said Aaron Wilson, an atmospheric scientist at Ohio State University’s Byrd Polar & Climate Research Center. “For instance, in the summer time, we see a lot more of the record warm temperatures happening at night than during the day.”
With warming temperatures, there’s more moisture entering the atmosphere, he said.
“That means during the daytime, our air temperatures don’t warm up as much as they would if it’s dry. Right? Because that water vapor is absorbing that energy. Then at nighttime, what happens is our air doesn’t cool off as much as it used to,” Wilson said.
Last year, 12 nights in Columbus hit the warmest night for that date on record.
“If you look at our wintertime temperatures, our winters are not as cold as they used to be,” Wilson said.
If you look at those nighttime lows in the winter, generally across the Midwest including Ohio, they’re about two to three degrees warmer than they were in the mid-20th century, he said.
The AP shared the data analysis with several climate and data scientists, who all said the conclusion was correct, consistent with scientific peer-reviewed literature and showing a clear sign of human-caused climate change.
Former Weather Channel meteorologist Guy Walton said the trend is unmistakable. He has been studying hot and cold extreme records since 2000.
“You are getting more extremes,” Walton said. “Your chances for getting more dangerous extremes are going up with time.”
No place has that been more noticeable than in the southern California city of Pasadena, where 7,203 days went by between cold records being broken. On Feb. 23, Pasadena set a low-temperature record, its first since June 5, 1999. In between the two cold-record days, Pasadena set 145 hot records. That includes an all-time high of 113 degrees last year.
The AP only considered daily — not all-time — high maximum temperatures and low minimum temperatures and only used stations with minimal missing data. Temperatures that tied previous records were counted in addition to temperatures that broke previous records.
More typical than Pasadena is Wooster, Ohio. From 1999 on, Wooster, which is 96 miles northeast of Columbus, saw 106 high-temperature records set or broken and 51 cold ones. In the previous eight decades, the ratio was slightly colder than 1-to-1.
People are lining up for air conditioning installation as the climate seems to get hotter over the years, said Lori Bowersock, who coordinates HVAC installations at MW Robinson Co., which serves Wooster and the rest of Wayne County.
“It’s more and more every year,” Bowersock said. “Usually we don’t have them lined up like this.”
The AP’S other findings: • Since Jan. 1, 1999, just under half the 424 weather stations had at least twice as many hot records set than cold ones, including Wooster.
• In all, 87 percent of the weather stations had more hot records than cold since 1999. There have been 42 weather stations that have at least five hot records for every cold one since 1999, with 11 where the hot-tocold ratio is 10-to-1 or higher, including Pasadena.
• Most decades in the 20th century had close to an even ratio of hot to cold. The 1930s, driven by Dust Bowl summers, had about 1.4 hot records for every cold. The 1960s and 1970s had about 1.5 cold records for every hot. The 21st century has a 1.9-to-1 hotto-cold ratio.