Arctic sea ice fell to record low for May. Greenland temperatures break record

Nuuk, Greenland’s capital, soared to 75 degrees (24 Celsius) Thursday, marking the warmest temperature ever recorded in the Arctic country during June. Nuuk sits on Greenland’s southwest coast, where the country’s warmest weather typically occurs.

It was warmer in Nuuk than it was in New York City, where the high was only 71 degrees.

The Danish Meteorological Institute has confirmed on a preliminary basis that the Nuuk measurement would replace the previous record of 73.8 degrees (23.2 Celsius), which was set in Kangerlussuaq on June 15 in 2014. That temperature was also recorded in southwest Greenland about 200 miles (320 km) north of Nuuk.

The news raised memories of the record melt season in 2012, when the ice sheet as a whole lost 562 gigatons, or billion tons, of freshwater mass to the ocean, enough to raise sea levels the world over by more than a millimeter in that year alone.

That included a moment in July of that year when in just a few days, the vast majority of the ice sheet’s surface became awash in at least some surface water, captured in this now iconic image from NASA:

The 2012 melt season, according to the National Snow and Ice Data Center, experienced melting even at mountainous heights over a mile into the sky atop Greenland. “During a peak melt event in July, even the summit areas of the ice sheet, nearly two miles above sea level, saw snowmelt conditions,” the group wrote. “While this has been observed in ice cores a handful of times in the past 1,000 years, it had not previously occurred in this century.”

In recent years Greenland has been losing so much mass that, along with changes in Antarctica and the amount of water stored on the globe’s continents, it appears to be having a subtle but measurable effect on the rotation of the Earth itself.

Researchers attributed the surprising early melt this year to weather conditions, and more specifically, a warm midlatitude air mass getting stuck over the ice sheet. “The strong south air flow onto Greenland has produced warm air, rain instead of snow, and melting of snow that is in Nuuk,” Greenland’s capital, Jason Box, a researcher with the Geological Survey of Denmark and Greenland, said by email.

This is similar to what appears to have happened in 2012, according to new research by Box and his colleagues, who found that it wasn’t just direct solar radiation that caused the bulk of the melting in 2012, but rather warm and cloudy weather conditions.

John Cappelen, a senior climatologist at the DMI, told The Washington Post that the warm weather was brought on by winds from the east that set up between high pressure over northeast Greenland and low pressure south of Greenland. When winds come from the east over Nuuk, they blow downhill, which leads to an increase in temperature. This is the result of adiabatic warming, where air is compressed from low pressure (at the top of a mountain) to high pressure (at sea level). It’s the same kind of dry warmth that occurs as a result of Santa Ana winds in Southern California.

Thursday’s toasty reading in Nuuk marks the second exceptionally warm temperature recorded in southwest Greenland since April, when the ice melt season began about a month prematurely.

On April 11, Kangerlussuaq hit a record high of 64.4 degrees (17.8 Celsius). “This was the warmest April temperature on record at that location, and it nearly set an all-time warm temperature record for Greenland as a whole,” reported Mashable’s Andrew Freedman.

At the time, so much ice was melting that scientists at the DMI couldn’t believe what they were seeing. “We had to check that our models were still working properly,” said Peter Langen, a climate scientist.

This week, the institute announced that Greenland’s ablation season, the period when its ice sheet loses more mass from melting along its edges than it does from snowfall in its interior, started on June 6. The DMI defines the start of this season when Greenland loses more than one gigaton of ice to the ocean. On the first three days of the month, Greenland lost 1.6, 2.2 and 2.4 gigatons of ice, the institute reports.

“This is the sixth earliest onset of ice loss in our 27-year record, although there isn’t really a large difference from one year to the next in the top-ranking 17 years,” said climate scientist Peter Langen.

Greenland’s exceptional warmth in 2016 piles on to other record-warm milestones established in recent years. In 2012, the temperature in Narsarsuaq, on the southern coast, soared to 76.6 degrees in May — a new monthly record, according to Jeff Masters at Weather Underground.

The next year, on July 30, 2013, the temperature at the observing station in Maniitsoq, on Greenland’s southwest coast,  soared to 78.6 degrees (25.9 Celsius) becoming Greenland’s warmest July temperature and warmest of any month.

(Official weather records in Greenland only date to 1958, and historical records indicate that on June 23, 1915, the temperature may have reached 86 degrees (30.1 C) in Ivigtut.)

The temperatures and early ice melt in Greenland are consistent with a pattern of exceptional warmth in the Arctic. Temperatures have frequently averaged well over 10 degrees above normal on the icy continent, and the extent of Arctic sea ice has set record lows most months.

It was also the warmest winter on record across the Arctic, says the National Snow and Ice Data Center, which reported that large areas recorded their “warmest conditions in 67 years of weather model data, including the northern half of the Greenland ice sheet.”

This year could be worst ever for melt as data shows average sea ice extent for last month was more than half a million square kilometres smaller than the previous record of May 2012.  Meanwhile, temperatures in Greenland surpassed those in much lower latitudes, such as New York, this past week.

Fragmented ice in the southern Beaufort Sea in the Arctic on 21 May 2016.
Fragmented ice in the southern Beaufort Sea in the Arctic on 21 May 2016. Photograph: Modis/Nasa

Data published by the US National Snow and Ice Data Centre (NSIDC) this week showed average sea ice extent for last month was more than 500,000 sq km (193,000 sq miles) smaller than May 2012.

The extent of sea ice in the Arctic is one of the key indicators of global warming, and the new findings have been greeted with concern by scientists. Although it is too early to say whether this summer’s ice extent will be the lowest recorded, if current projections follow the course of previous years then it will be at least one of the lowest ever.

Snow cover in the northern hemisphere was the lowest in 50 years in April, the NSIDC said, and Antarctic sea ice was below average for the time of year.

Monthly May Arctic sea ice extent for 1979 to 2016 shows a decline of 2.6% per decade
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Monthly May Arctic sea ice extent for 1979 to 2016 shows a decline of 2.6% per decade. Photograph: NSIDC

Warm air from Siberia and northern Europe were blamed for the decline in Arctic sea ice, which is consistent with predictions of climate change. The Arctic has warmed much faster than other regions, and the loss of sea ice is viewed as a measure of how much we are affecting the world’s climate.

Melting sea ice does not raise sea levels, because the ice is floating, but has a strong effect on the earth’s albedo – the reflectivity of the poles and other snow and ice covered areas. Ice and snow reflect some of the sun’s heat back into space, but when they retreat the dark areas remaining absorb more heat. This exacerbates existing warming effects, such as the accumulation of greenhouse gases in the atmosphere.

In addition, melting sea ice in the Arctic is often a good indicator that land ice and snow – such as that which covers Greenland – is also melting, and land-based ice does contribute to sea level rises.

The NSIDC cautioned that current sea ice estimates were “tentative”, but added that they were “supported by other data sources”. The extent of sea ice will be closely watched this summer, as the lowest point of the year comes in September as the Arctic summer draws to a close.

Jonathan Bamber, professor of physical geography at Bristol University, told the Guardian: “We have already seen an unusually early start to melting around the margins of Greenland in 2016 and the new findings from NSIDC of exceptionally low sea ice extent for May and the lowest northern hemisphere snow cover for 50 years is in line with the longer term decadal trends for the Arctic as a whole. The region is undergoing warming at around twice the global average, and the ice is responding accordingly.”

Temperatures in the Arctic last winter were up to 10C above the average for 1981 to 2010, said Chris Rapley, professor of climate science at University College London. He also highlighted the reduction in thickness of the ice, which is another key indicator of climate change.

“The impacts on the Arctic ocean and land systems are transformational, creating huge problems for [people who live there] who on the basis of their traditional knowledge confirm that the climate system has already shifted well outside the bounds they have previously experienced. The situation is [also] changing the circulation patterns and behaviours of the atmosphere and oceans,” he said

Arctic Sea Ice Age in May 1984 and May 2014. Credits: NSIDC/Nasa

The reduced extent of this summer’s ice is also a hangover from last winter, when sea ice was unusually slow to form because of higher temperatures in the surrounding oceans, according to Dr Finlo Cottier, senior lecturer in polar oceanography at the Scottish Association for Marine Science.

“This [slow formation of winter ice] leads to thinner ice that can break up more easily,” said Cottier. “The results also highlight the increasing significance of wind in deforming and breaking the sea ice cover.”

Sea ice extent in the last winter was at its smallest extent for winter since records began in 1979, data published in March showed.

Research by the campaigning group Greenpeace, published this week, suggests that melting ice in the Arctic may also alter weather patterns in the northern hemisphere, contributing to wetter summers in some areas and colder, stormy winters.