Unprecedented Melting of Greenland Ice Sheet and the Arctic Ocean Took Temperatures To 40 Degrees Beyond Normal in June
For the first time, the Arctic is experiencing an unexpected and exceptional melting of ice with the advent of summer. Recently, record-breaking ice melting was observed over the Greenland ice sheet, especially during mid-June period. The expanse of ice over the Arctic Ocean has never experienced this low during the same period in the weather satellites age.
The temperatures unexpectedly rose up to 40 degrees above average in Greenland on Wednesday, while in places north of Alaska, the open water seems to exist where it seldom does, if ever, but in recent times.
It’s “another series of extreme events consistent with the long-term trend of a warming, changing Arctic,” said Zachary Labe, a climate researcher at the University of California at Irvine.
The melting of ice in the Arctic along with the abnormal warmth may be messing with our weather.
The Ice Sheet of Greenland
National Snow and Ice Data Center’s data is showing that the Greenland ice sheet experienced its biggest melt event on record this week so early in this season (although similar mid-June melting also demonstrated by few other years).
“The melting is big and early,” said Jason Box, an ice climatologist at the Geological Survey of Denmark and Greenland.
The temperatures over the western Greenland ice sheet have been abnormally high while snow has been well below normal, Box explained.
An ice researcher at Columbia University, Marco Tedesco said that east and central Greenland has been unusually warm. “This has triggered widespread melting that has reached about 45 percent of the ice sheet,” he wrote in an email.
Typically, until midsummer, this widespread melting over the ice sheet doesn’t occur, if even then.
According to a simulation from the European Centre for Medium-range Weather Forecasting, on Wednesday, the temperatures over Greenland may have reached at its highest around 40 degrees above normal.
There was a big dome of high pressure over Greenland, resulting in sunny skies and mild temperatures enabling the melting. An automated weather station located at the top of Greenland’s ice sheet topped freezing on June 12 which is a rare event that occurred last time in July 2012.
Greenland ice sheet witnessed the most melting on record in 2012. However, people who are monitoring the ice sheet say the melting in 2019 could compete for that. The coming months’ weather will determine how much more the ice sheet melts and whether 2019 is going to set a new record. A climatologist at the University of Liège in Belgium, Xavier Fettweis tweeted, if high pressure becomes stable, “we should break a new record.” However, scientists studying the region are well aware that in Greenland weather varies highly and change rapidly.
Mike MacFerrin, a glaciologist at the University of Colorado, put it this way in a tweet: “2019 has been… anomalous… so far, but also quite variable. It’s early and weather is weather, so keep your eyes peeled. …”
Sea Ice of Arctic
Since 1979, weather satellites are monitoring the sea ice in the Arctic, and at the recent time, mid-June ice coverage is the lowest on record.
The ice extent in the part of the Arctic Ocean adjacent to the Pacific Ocean has been especially depleted. “It’s pretty remarkable how much open water is in that area,” Labe said.
As per Labe, the sea ice has been pulled away from the northern Alaska coast by the high pressure over the Arctic.
According to Rick Thoman, a climatologist based in Fairbanks, loss of sea ice over the Chukchi and Beaufort seas along Alaska’s northern coast has been “unprecedented.”
There’s sufficient open water that you could sail from the Bering Strait into a narrow opening just north of Utqiagvik, Alaska’s northernmost city, clear into the Beaufort Sea, Labe said. “It’s very unusual for open water this early in this location,” he said.
Ocean temperatures in this region will rise due to entire exposed water, Labe said, causing a delay in the customary fall freeze and will probably result in a historically low late-summer sea ice minimum, usually in the middle of the September.
The weather in the coming months will decide whether the Arctic sea ice minimum is record-setting, like the Greenland ice sheet.
“There is no indication that this year will be as low as 2012,” when Arctic sea ice reached its lowest extent on record, Labe said. “If cloudy weather occurs, it would slow down the rate [of melting]. It’s really hard to predict.”
Understanding the Impact of Weather on the United States
The implication of Arctic’s extreme conditions resulting in record melt events is widespread. There is a saying often repeated by Arctic researchers: “What happens in the Arctic doesn’t stay in the Arctic.”
Arctic’s bulging zones of high pressure which have created the unusual warmth and intensified melting are shifting the region’s cold air into the mid-latitudes as if a refrigerator door is left open. Many places of the central and eastern United States have experienced lower-than-normal temperatures in the last week.
An unusually erratic meander of the jet stream, the high-altitude current separating cold air and warm air, has been noticed.
“The jet stream this week was one of the craziest I’ve ever seen!” Jennifer Francis, one of the leading researchers who has published studies connecting Arctic change and mid-latitude weather, wrote in an email.
Earlier Francis had suggested that the Arctic’s condition may have played a role in the extreme jet stream pattern that spurred the tornado swarm and record flooding in the central U.S. during the last two weeks of May. “We can’t say that the rapid Arctic warming is causing this particular pattern, but it certainly is consistent with that,” Francis, senior scientist at Woods Hole Research Center, said.