Quantcast

Greenland Melting Is ‘Off the Charts’

Climate
Birthday Canyon on the Greenland Ice Sheet. James Balog / Getty Images

The first continuous, multi-century study of surface melt from the Greenland ice sheet was published in Nature Wednesday, and the results are clear: the ice sheet is now melting at rates unseen within at least the last 350 years.


"Melting of the Greenland Ice Sheet has gone into overdrive. As a result, Greenland melt is adding to sea level more than any time during the last three and a half centuries, if not thousands of years," lead study author and Rowan University School of Earth & Environment glaciologist Luke Trusel said in a press release from the Woods Hole Oceanographic Institution (WHOI), one of the institutions involved in the research.

Greenland is Melting Faster than Ever www.youtube.com

The researchers found that melting first increased on the ice sheet in the 1800s, when the Arctic began to warm as the process of industrialization started pumping greenhouse gasses into the atmosphere. However, it is only in recent decades that the melting has increased beyond the point of natural variability. There is now 50 percent more meltwater runoff entering the oceans from the sheet since the start of the industrial era, and 30 percent more since the 20th century.

"From a historical perspective, today's melt rates are off the charts, and this study provides the evidence to prove this," WHOI glaciologist and study author Sarah Das said.

The researchers were able to prove what many had sensed through observation by using a novel method, as the WHOI explained:

To determine how intensely Greenland ice has melted in past centuries, the research team used a drill the size of a traffic light pole to extract ice cores from the ice sheet itself and an adjacent coastal ice cap, at sites more than 6,000 feet above sea level. The scientists drilled at these elevations to ensure the cores would contain records of past melt intensity, allowing them to extend their records back into the 17th century. During warm summer days in Greenland, melting occurs across much of the ice sheet surface. At lower elevations, where melting is the most intense, meltwater runs off the ice sheet and contributes to sea level rise, but no record of the melt remains. At higher elevations, however, the summer meltwater quickly refreezes from contact with the below-freezing snowpack sitting underneath. This prevents it from escaping the ice sheet in the form of runoff. Instead, it forms distinct icy bands that stack up in layers of densely packed ice over time.

Using ice cores allowed the researchers to provide more historical context than the satellite data they had relied on up until now to judge melt rates, which only goes back to the 1970s.

"We have had a sense that there's been a great deal of melting in recent decades, but we previously had no basis for comparison with melt rates going further back in time," study author and MIT-WHOI graduate student Matt Osman said. "By sampling ice, we were able to extend the satellite data by a factor of 10 and get a clearer picture of just how extremely unusual melting has been in recent decades compared to the past."

The research has troubling implications for future sea level rise, because it shows that the ice sheet isn't melting at a steady rate. Instead, each degree of warming increases the amount of melting, meaning the more the planet warms, the more sensitive the ice sheet will be.

"Even a very small change in temperature caused an exponential increase in melting in recent years," Das said. "So the ice sheet's response to human-caused warming has been non-linear."

Trusel summed up the implications:

"Warming means more today than it did in the past," he said.

The research is in keeping with estimates that global sea levels will rise by eight to 12 inches by 2050, but University of Lincoln climate scientist Edward Hanna, who was not involved with the study, told InsideClimateNews that sea level rise projections might have to be increased if Greenland keeps melting.

"We can't rule out that the IPCC (Intergovernmental Panel on Climate Change) sea level rise scenarios are too conservative," Hanna said. "Greenland is a bit like a sleeping giant that is awakening. Who knows how it will respond to a couple of more degrees of warming? It could lose a lot of mass very quickly."

EcoWatch Daily Newsletter

Tim P. Whitby / 21st Century Fox / Getty Images

The beauty products we put on our skin can have important consequences for our health. Just this March, the U.S. Food and Drug Administration (FDA) warned that some Claire's cosmetics had tested positive for asbestos. But the FDA could only issue a warning, not a recall, because current law does not empower the agency to do so.

Michelle Pfeiffer wants to change that.

The actress and Environmental Working Group (EWG) board member was spotted on Capitol Hill Thursday lobbying lawmakers on behalf of a bill that would increase oversight of the cosmetics industry, The Washington Post reported.

Read More Show Less
A protest march against the Line 3 pipeline in St. Paul, Minnesota on May 18, 2018. Fibonacci Blue / CC BY 2.0

By Collin Rees

We know that people power can stop dangerous fossil fuel projects like the proposed Line 3 tar sands oil pipeline in Minnesota, because we've proved it over and over again — and recently we've had two more big wins.

Read More Show Less
Sponsored
Scientists released a study showing that a million species are at risk for extinction, but it was largely ignored by the corporate news media. Danny Perez Photography / Flickr / CC

By Julia Conley

Scientists at the United Nations' intergovernmental body focusing on biodiversity sounded alarms earlier this month with its report on the looming potential extinction of one million species — but few heard their calls, according to a German newspaper report.

Read More Show Less
DoneGood

By Cullen Schwarz

Ethical shopping is a somewhat new phenomenon. We're far more familiar with the "tried and tested" methods of doing good, like donating our money or time.

Read More Show Less
Pixabay

Summer is fast approaching, which means it's time to stock up on sunscreen to ward off the harmful effects of sun exposure. Not all sunscreens are created equally, however.

Read More Show Less
Sponsored
Mark Wallheiser / Getty Images

The climate crisis is a major concern for American voters with nearly 40 percent reporting the issue will help determine how they cast their ballots in the upcoming 2020 presidential election, according to a report compiled by the Yale Program on Climate Change Communication.

Of more than 1,000 registered voters surveyed on global warming, climate and energy policies, as well as personal and collective action, 38 percent said that a candidate's position on climate change is "very important" when it comes to determining who will win their vote. Overall, democratic candidates are under more pressure to provide green solutions as part of their campaign promises with 64 percent of Democrat voters saying they prioritize the issue compared with just 34 percent of Independents and 12 percent of Republicans.

Read More Show Less
Flooding in Winfield, Missouri this month. Jonathan Rehg / Getty Images

President Donald Trump has agreed to sign a $19.1 billion disaster relief bill that will help Americans still recovering from the flooding, hurricanes and wildfires that have devastated parts of the country in the past two years. Senate Republicans said they struck a deal with the president to approve the measure, despite the fact that it did not include the funding he wanted for the U.S.-Mexican border, CNN reported.

"The U.S. Senate has just approved a 19 Billion Dollar Disaster Relief Bill, with my total approval. Great!" the president tweeted Thursday.

Read More Show Less
Reed Hoffmann / Getty Images

Violent tornadoes tore through Missouri Wednesday night, killing three and causing "extensive damage" to the state's capital of Jefferson City, The New York Times reported.

"There was a lot of devastation throughout the state," Governor Mike Parson said at a Thursday morning press conference, as NPR reported. "We were very fortunate last night that we didn't have more injuries than what we had, and we didn't have more fatalities across the state. But three is too many."

Read More Show Less