July saw 3,135 new daily high temperature records in the U.S. — over 100 per day. That overwhelmed new cold records by a factor of nearly 17 to 1, as this chart from Capital Climate shows.
For the year to date, new heat records are beating cold records by a remarkable 12 to 1, which trumps the pace of the last decade by more than a factor of 5!
I like the statistical aggregation across the country, since it gets us beyond the oft-repeated point that you can’t pin any one local record temperature on global warming. A 2009 analysis shows that the average ratio for the 2000s was 2.04-to-1, a sharp increase from previous decades. Lead author Dr. Gerald Meehl explained, “If temperatures were not warming, the number of record daily highs and lows being set each year would be approximately even.”
Many of the country’s leading meteorologists and climatologists — including NASA’s James Hansen — have looked at the data and concluded that like a baseball player on steroids, our climate system is breaking records at an unnatural pace.
One state in particular is ground-zero for global warming this summer, just as it was last summer (see my 8/11 post “Oklahoma Sees Hottest Average Temperature of Any State on Record“). And coincidentally, it is the home state of the Senate’s leading global warming denier.
Most of Oklahoma has experienced eight consecutive days with highs of 100° or more, and many regions, including Oklahoma City, have had a streak of 17 such days. Image credit: Oklahoma Mesonet (via Masters).
Meteorologist Dr. Jeff Masters had a good summary yesterday of the searing statistics and why “Oklahoma will likely endure another hellish day of extreme heat, dryness, and fires”:
Historic heat wave in Oklahoma
A historic heat wave and drought fueled raging fires on Friday in Oklahoma. The fires destroyed at least 65 homes, forced multiple evacuations, and closed major roads. Oklahoma City had its hottest day in history, hitting 113°, tying the city’s all-time heat record set on August 11, 1936. The low bottomed out at 84°, the warmest low temperature ever recorded in the city (previous record: a low of 83° on August 13, 1936.) Oklahoma City has now had three consecutive days with a high of 112° or higher, which has never occurred since record keeping began in 1891.
With today’s high expected to reach 113° again, the streak may extend to four straight days. Yesterday was the third consecutive day with more than a third of Oklahoma experiencing temperatures of 110° or higher, according to readings from the Oklahoma Mesonet. NOAA’s Storm Prediction Center (SPC) declared a “Critical” fire weather day over most of Oklahoma yesterday, due to extreme heat and drought, low humidities, and strong winds. Between 4 – 5 pm CDT Friday, Oklahoma City had a temperature of 113°, a humidity of 12%, and winds of 14 mph gusting to 25 mph. Another “Critical” fire weather day has been declared for Saturday. A cold front approaching from the northwest will bring winds even stronger than Friday’s winds, and Oklahoma will likely endure another hellish day of extreme heat, dryness, and fires.
Only comparable heat wave: August 1936
The only heat wave in Oklahoma history that compares to this week’s occurred in the great Dust Bowl summer of 1936, the hottest summer in U.S. history. Oklahoma City experienced three days at 110° that summer, and a record streak of 22 straight days with a temperature of 100° or hotter. Those numbers are comparable to 2012′s: three days at 110° or hotter, and a string of 17 consecutive days with temperatures of 100° or hotter.
It’s worth noting that Oklahoma City has experienced only 11 days since 1890 with a high of 110° or greater. Three of those days were in 2011, three were in 2012, and three were in the great Dust Bowl summer of 1936. Clouds moved in over Tulsa, Oklahoma yesterday, holding down the high temperature to just 107°, ending that city’s 3-day streak of 110°+ days. The only longer streak was 5 consecutive days on August 9 – 13, 1936.
As I explained in my Nature article last year on “The next dust bowl” (full text here), we expect the greatest number of temperature records to be set during a widespread drought:
Warming causes greater evaporation and, once the ground is dry, the Sun’s energy goes into baking the soil, leading to a further increase in air temperature. That is why, for instance, so many temperature records were set for the United States in the 1930s Dust Bowl; and why, in 2011, drought-stricken Texas saw the hottest summer ever recorded for a US state.
Much as our current monster heat wave has been made worse by human activity (man-made global warming) so too was the Dust Bowl — but in that case it was bad agricultural practices, as I discussed last month.
And that’s worrisome because the Earth has warmed only a bit more than 1°F since the catastrophic Dust Bowl — and we are poised to warm an astounding 9-11°F this century if we stay anywhere near our current greenhouse gas emissions path.
In short, we ain’t seen nothing yet!