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

By Jared Kaufman

Eating a better diet has been linked with lower levels of heart disease, stroke and type 2 diabetes. But unfortunately 821 million people — about 1 in 9 worldwide — face hunger, and roughly 2 billion people worldwide are overweight or obese, according to the U.N. World Health Organization. In addition, food insecurity is associated with even higher health care costs in the U.S., particularly among older people. To help direct worldwide focus toward solving these issues, the U.N. Sustainable Development Goals call for the elimination of hunger, food insecurity and undernutrition by 2030.

Read More Show Less
Healthline

Made from the freshly sprouted leaves of Triticum aestivum, wheatgrass is known for its nutrient-dense and powerful antioxidant properties.

Read More Show Less
Sponsored
Golde Wallingford submitted this photo of "Pure Joy" to EcoWatch's first photo contest. Golde Wallingford

EcoWatch is pleased to announce our third photo contest!

Read More Show Less

mevans / E+ / Getty Images

The federal agency that manages the Great Barrier Reef issued an unprecedented statement that broke ranks with Australia's conservative government and called for urgent action to reduce greenhouse gas emissions, according to the Guardian.

Read More Show Less

A powerful earthquake struck near Athens, Greece and shook the capital city for 15 seconds on Friday, causing people to run into the streets to escape the threat of falling buildings, NBC News reported.

Read More Show Less
Sponsored
U.S. government scientists concluded in a new report that last month was the hottest June on record. Angelo Juan Ramos / Flickr

By Jessica Corbett

As meteorologists warned Thursday that temperatures above 100°F are expected to impact two-thirds of the country this weekend, U.S. government scientists revealed that last month was the hottest June ever recorded — bolstering calls for radical global action on the climate emergency.

Read More Show Less
Rod Waddington / CC BY-SA 2.0

By John R. Platt

For years now conservationists have warned that many of Madagascar's iconic lemur species face the risk of extinction due to rampant deforestation, the illegal pet trade and the emerging market for the primates' meat.

Yes, people eat lemurs, and the reasons they do aren't exactly what we might expect.

Read More Show Less
Pixnio

By Rachael Link, MS, RD

Many types of flour are commonly available on the shelves of your local supermarket.

Read More Show Less