Record Highs vs. Record Lows

July 10, 2013 marks the 100th anniversary of the all-time highest temperature ever recorded on Earth: 134°F, measured in Death Valley, California in July of 1913. The recent extreme heat across the West brought that record back into the spotlight. Even though the 129 degree reading on June 30 of this year fell short of the all-time temperature, it did set a new June record both for Death Valley and for the entire United States.

So in a world with global warming, how does a record stand for 100 years? Even in a warmer world, we will still get natural variability with record lows, just as we got an all-time record high back in 1913 before global warming kicked in. But on average, the number of record highs is outpacing the number of record lows by a bigger margin each decade - as shown in the graphic above. If there was no warming trend, you would see the number of record highs more closely matching the number of record lows over the span of a decade.

A Climate Central report “The Heat Is On” took a closer look at the temperature trend for each state in the contiguous United States two different ways: 1) over the last 100 years (right around the time the Death Valley record was set) and 2) from 1970 on. The findings showed that all but three states (Georgia, Arkansas and Alabama) have warmed over the past century, but even those three states show a temperature rise from 1970 on.

Death Valley hasn’t always held the record, though. Just a year ago, it was stuck firmly in second place behind a 136°F reading taken in El-Aziza, Libya in 1922. But while the Libyan claim was listed in the Guinness Book of World Records, meteorologists have always been dubious: the thermometer that took the reading was obsolete technology even back then, while nearby weather stations recorded temperatures 18°F cooler on the same day. Last September, an investigation by the World Meteorological Organization reached a verdict: El-Aziza was bunk; Death Valley rules. Scientists and heat lovers are celebrating that record with festivities at the Furnace Creek Visitor Center this afternoon.