(earth.nullschool.net)

Greenland and its ice sheet have warmed briskly in recent years, and this summer — like most in recent years — has been warmer than normal.

But in July’s final moments, at the apex of Greenland’s ice sheet, the mercury plunged to 23 degrees below zero (-30.7 Celsius).

The frigid measurement at Summit Station set a record low for the month according to the Danish Meteorological Institute. It was 5 degrees (3 Celsius) colder than the previous record set in 1992.


Summit Station, Greenland. (NOAA)

Several blogs run by climate change doubters have touted the record as if to suggest it is evidence that flies in the face of global warming.

But it’s nothing of the sort. It’s simply a curiosity that serves as an interesting contrast to recent record warmth.

Consider temperature measurements have been kept at Summit Station only since about 1990, which is “not worth much,” according to Jason Box, an Arctic climate researcher with the Geological Survey of Denmark. Box said the extreme was “interesting” in isolation but noted that the melting on the surface of Greenland’s ice sheet was above normal during July.

“I wouldn’t start screaming Greenland is cooling down,” added Marco Tedesco, a Greenland expert based at the Lamont-Doherty Earth Observatory at Columbia University.

Konrad Steffen, principal investigator of Greenland’s Climate Network, agreed that the cold spell was “nothing significant.” He said that despite the record, the cold was fairly ordinary and similar conditions had occurred in other years.

Much more often than not, Greenland has been unusually warm.

Earlier this year, Greenland logged its highest June and April temperatures ever recorded. These records were established in Southwest Greenland.

Summit Station, at an altitude of almost 10,500 feet (3,200 meters) near Greenland’s center, is among its coldest locations. At the end of July, a very strong area of Arctic high pressure was parked nearby.


Surface pressure difference from normal July 31 across Northern Hemisphere. Notice the huge positive anomaly over the Greenland ice sheet. (NOAA)

“The anomalous high pressure would likely drive large longwave radiative losses … inducing (record) cold temperatures,” explained Daniel McGrath, a research scientist at Colorado State University, who has studied Greenland temperature trends.

But despite this bitter cold, Summit Station has warmed at a feverish pace in recent decades. McGrath led a study published in 2013 that concluded  that Summit Station warmed at a rate “six times the global average” and “in the 99th percentile of all globally observed warming trends” between 1982 and 2011.

This summer has also been much warmer than average. Tedesco said that since April 1, temperatures at high-elevation weather stations in Greenland, including Summit Station, have been about 1 degree Celsius warmer than normal. “At lower elevations, we are talking about 3 Celsius above the mean for the same period,” he said.


Temperature difference from normal (in Celsius) over Greenland and surrounding areas in July. (Jason Box)

Weather data from the Danish Meteorological Institute show warm weather extremes vastly outnumbering cold weather extremes in recent years.

Of all of Greenland’s monthly record warm temperatures, 8 of 12 have occurred since 2000, and 10 of 12 since 1990. By contrast, all of Greenland’s monthly record cold temperatures (excluding those at Summit Station) occurred before 2000. Records date back to 1958.