Greenland Is Melting Away Before Our Eyes

Greenland Is Melting Away Before Our Eyes

SOURCE: Rolling Stone DATE: July 31, 2019 SNIP: Amid an ongoing heat wave, new data show the Greenland ice sheet is in the middle of its biggest melt season in recorded history. It’s the latest worrying signal climate change is accelerating far beyond the worst fears of even climate scientists. The record-setting heat wave that sweltered northern Europe last week has moved north over the critically vulnerable Greenland ice sheet, triggering temperatures this week that are as much as 25 to 30 degrees Fahrenheit warmer than normal. Weather models indicate Tuesday’s temperature may have surpassed 75 degrees Fahrenheit in some regions of Greenland, and a weather balloon launched near the capital Nuuk measured all-time record warmth just above the surface. That heat wave is still intensifying, and is expected to peak on Thursday with the biggest single-day melt ever recorded in Greenland. On August 1 alone, more than 12 billion tons of water will permanently melt away from the ice sheet and find its way down to the ocean, irreversibly raising sea levels globally. A tweet from the Danish Meteorological Institute, the official weather service of Greenland, said “almost all the ice sheet, including Summit” measurably melted on Tuesday. According to a preliminary estimate, that melt covered 87 percent of the ice sheet’s surface, which would be the second-biggest melt day in Greenland’s recorded history. Separate weather monitoring equipment at Summit Camp at the top of the 10,000-foot-thick Greenland ice sheet confirmed the temperature briefly reached the melting point. This week alone, Greenland will lose about 50 billion tons of ice, enough for a permanent rise in global sea...
Study Predicts More Long-Term Sea Level Rise from Greenland Ice

Study Predicts More Long-Term Sea Level Rise from Greenland Ice

SOURCE: NASA DATE: June 19, 2019 SNIP: In the next 200 years, the ice sheet model shows that melting at the present rate could contribute 19 to 63 inches to global sea level rise, said the team led by scientists at the Geophysical Institute at the University of Alaska Fairbanks. These numbers are at least 80 percent higher than previous estimates, which forecasted up to 35 inches of sea level rise from Greenland’s ice. The team ran the model 500 times out to the year 3000 for each of three possible future climate scenarios, adjusting key land, ice, ocean and atmospheric variables to test their effects on ice melt rate. The three climate scenarios depend on the amount of greenhouse gas emissions in the atmosphere in coming years. In the scenario with no reduction of emissions, the study found that the entire Greenland Ice Sheet will likely melt in a millennium, causing 17 to 23 feet of sea level rise. Capturing the changing flow and speed of outlet glacier melt makes the updated ice sheet model more accurate than previous models, according to the authors. As ocean waters have warmed over the past 20 years, they have melted the floating ice that shielded the outlet glaciers from their rising temperatures. As a result, the outlet glaciers flow faster, melt and get thinner, with the lowering surface of the ice sheet exposing new ice to warm air and melting as well. Each of the three emissions scenarios used in the study produced different patterns of ice retreat across Greenland. The least severe scenario showed the ice retreating in the west...
Rain may be causing a worrying amount of ice to melt in Greenland

Rain may be causing a worrying amount of ice to melt in Greenland

SOURCE: New Scientist DATE: March 7, 2019 DATE: Rain is becoming more common across Greenland’s ice sheet and it may be playing an important role in rising sea levels. Greenland’s 660,000-square mile ice sheet contains enough fresh water to flood coastal cities around the world. Warm air over the sheet is causing it to melt, but new work reveals that rainfall is also causing more melting than previously thought. An analysis of satellite and weather station records suggests that around 300 melt events in Greenland between 1979 and 2012 were linked to rainfall. Over this time, rain-associated melting became twice as frequent in summer, and three times as frequent in winter. Rain now appears to account for 28 per cent of the ice sheet’s melt. When precipitation falls as rain, it causes some of Greenland’s ice sheet to be covered in ice rather than snow. Come the summer, this ice reflects less of the sun’s energy, exacerbating summer melting. Historically, Greenland’s melt season has run between May and August, but rainfall means melting is now happening in winter too. “The rain events are extremely important because they are one of the only triggers for melting in winter,” says Marco Tedesco, of Columbia University in New York, who was involved in the...
Are we headed toward the worst-case climate change scenario?

Are we headed toward the worst-case climate change scenario?

SOURCE: Pacific Standard and New York Times DATE: January 25, 2019 SNIP: This week, researchers warned that Greenland’s ice sheet has reached a tipping point. Looking at more than a decade’s worth of ice loss, an international team of scientists found that the rate of Greenland’s ice loss in early 2013 was four times higher than in 2003. [I]n this new study, Michael Bevis, a professor at Ohio State University, and his colleagues were surprised to see that most of the ice loss occurred in the southwest corner of Greenland, a region with very few glaciers. In other words, most of the ice loss was in the form of meltwater runoff, draining from land-based ice sheets into the sea. What Bevis and his colleagues found was that the melting was being controlled by something called the North Atlantic Oscillation—an irregular fluctuation in atmospheric pressure over the Atlantic Ocean that influences the weather on several continents. “Global warming brought summertime temperatures just shy of the critical temperature at which massive melting would occur, and the NAO pushed it over this critical threshold,” he says. It means that the ice sheet is now sensitive to small fluctuations in summer temperatures, and if global temperatures continue to rise as predicted, soon Greenland’s summers will be warm enough to cause massive melting regardless of the NAO’s phase. The new research dovetails with other recent papers on the accelerating melting. Last month a team of researchers published a paper in Nature that used satellite observations, analysis of ice cores and models to show that losses from the Greenland ice sheet have reached their fastest...
Greenland ice melting rapidly

Greenland ice melting rapidly

SOURCE: Ohio State News and National Geographic DATE: January 21, 2019 SNIP: Greenland is melting faster than scientists previously thought—and will likely lead to faster sea level rise—thanks to the continued, accelerating warming of the Earth’s atmosphere, a new study has found. Scientists concerned about sea level rise have long focused on Greenland’s southeast and northwest regions, where large glaciers stream iceberg-sized chunks of ice into the Atlantic Ocean. Those chunks float away, eventually melting. But a new study published Jan. 21 in the Proceedings of the National Academy of Sciences found that the largest sustained ice loss from early 2003 to mid-2013 came from Greenland’s southwest region, which is mostly devoid of large glaciers. “Whatever this was, it couldn’t be explained by glaciers, because there aren’t many there,” said Michael Bevis, lead author of the paper, Ohio Eminent Scholar and a professor of geodynamics at The Ohio State University. “It had to be the surface mass—the ice was melting inland from the coastline.” That melting, which Bevis and his co-authors believe is largely caused by global warming, means that in the southwestern part of Greenland, growing rivers of water are streaming into the ocean during summer. The key finding from their study: Southwest Greenland, which previously had not been considered a serious threat, will likely become a major future contributor to sea level rise. “We knew we had one big problem with increasing rates of ice discharge by some large outlet glaciers,” he said. “But now we recognize a second serious problem: Increasingly, large amounts of ice mass are going to leave as meltwater, as rivers that flow...