An Italian army base near El Azizia, Libya in 1922, where the world’s hottest temperature of 58 degrees Celsius (136.4 F) was thought to have been recorded. (Courtesy of family of Italian General B.A. Enrico Pezzi)

This means Death Valley (Greenland Ranch, California), which saw the mercury soar to a scorching 134 degrees on July 10, 1913 now holds the distinction of having achieved the Earth’s hottest temperature.

“It is a figure that has been for meteorologists as Mt. Everest is for geographers,” wrote Christopher Burt, Weather Underground weather historian.

Thirteen scientists from 9 countries conducted a review of the Libyan record and uncovered 5 problems with the temperature measurement:

* use of antiquated instrumentation

* a likely inexperienced observer

* an observation site that was not representative of the desert surroundings

* poor matching of the temperature to nearby locations

* poor matching to temperatures recorded in that location after the record was established

“When we compared observations to surrounding areas and to other measurements made before and after the 1922 reading, they simply didn’t match up,” said Arizona State University meteorologist Randy Cerveny, who led the study on behalf of the World Meteorological Organization.

Video of Randy Cerveny discussing the world record temperature review

The 13 scientists began the investigation around the start of the revolution in Libya in 2010. It was forced into hiatus when the Libyan official involved, Khalid El Fadli, disappeared. He re-surfaced eight months later and work resumed.

“Khalid El Fadli did this at great risk to himself,” Cerveny said. “He was an official of the previous regime, so when the revolution began to turn, his safety was a key concern.”

The driving force behind the investigation was Weather Underground’s Christopher Burt, who long suspected the Libyan record was questionable.

Burt initially contacted El Fadli in 2010 to discuss the record. After El Fadli collegially shared data and information consistent with his suspicions (El Fadli was skeptical of the record himself), Burt reached out to Cerveny who created the committee to evaluate the record.

You can read Burt’s fascinating account of this entire process on the Weather Underground blog.

Related reading:

World’s hottest temperature cools a bit (official news release)

World Meteorological Organization Assessment of the Purported World Record 58ºC Temperature Extreme at El Azizia, Libya (13 September 1922) (study published in the Bulletin of the American Meteorological Society)