Huge Cracks in Antarctic Glacier Foreshadow Epic Calving Event

The European Space Agency (ESA) released a video this past week showing the evolution of two very large and disconcerting cracks in Antarctica’s Pine Island Glacier. They have each grown to 20km in length and could shear off a hunk of ice the size of Paris and Manhattan combined.

The Pine Island Glacier—located at the base of the Antarctic Peninsula on the western side of the continent—has always shipped Antarctic ice out to sea at prolific levels, but it’s become famous in recent years due to its ever increasing output. These new cracks are just the latest development in a flurry of epic calving events at Pine Island. These used to occur about every six years but are now happening on an almost yearly basis.

The ESA compiled images of the cracks taken by one of their two polar orbiting Sentinel-1 satellites to make the video. Sentinel-1 is continuously monitoring land, sea, and sea ice conditions with a synthetic-aperture radar instrument that allows it to take pictures in all weather conditions and even at night—a key feature in high latitudes, which experience long periods of darkness in the winter months.  These satellites are part of ESA’s larger Copernicus mission.

Pine Island Glacier feeds into a floating body of ice called an ice shelf. A recent study published in Science Advances this month revealed that these ice shelves, and Pine Island Glacier  in particular, are experiencing accelerated melting from underneath, as a combination of fast moving and buoyant plumes of warm water carve troughs into their bottom surface. This makes the shelves more prone to large calving events and ultimately to shrinkage and retreat.

Pine Island Glacier is made of ice from the West Antarctic ice sheet and flows into the Amundsen Sea. (Credit: NASA)

“Warm water circulation is attacking the undersides of these ice shelves at their most vulnerable points,” said lead earth scientist and lead author of the report, Karen Alley. “These effects matter,” she added. “But exactly how much, we don’t yet know. We need to.”

The large calving event building at Pine Island Glacier also comes at a period of particular concern for melting glaciers around the world. The International Panel on Climate Change released its special report on the state of the Earth’s cryosphere last month in which it predicted continued warming of ocean waters and increasing mass loss of the Antarctic Ice Sheets—of which Pine Island Glacier is a part—throughout the 21st century.

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Roundup: Hot Rocks, Dissolved Organic Matter, and Dry-Snow Densification

Elevated Geothermal Surface Heat Flow

From Earth and Planetary Science Letters: “This study provides ground-truth for regional indirect GHF [Geothermal Heat Flow] estimates in the Amundsen Sea Embayment, which is part of the West Antarctic Rift System, by presenting in situ temperature measurements in continental shelf sediments. Our results show regionally elevated and heterogeneous GHF (mean of 65 mWm-2) in the Amundsen Sea Embayment.

Read the research paper here.

Glaciers seen during NASA’s Operation IceBridge research flight to West Antarctica on Oct. 29, 2014 (Source: NASA/Michael Studinger).

 

Dissolved Organic Matter in an Arctic Fjord

From Limnology and Oceanography: “Arctic waters are often enriched with terrestrial dissolved organic matter (DOM) characterized by having elevated visible wavelength fluorescence (commonly termed humic-like). Here, we have identified the sources of fluorescent DOM (FDOM) in a high Arctic fjord (Young Sound, NE Greenland) influenced by glacial meltwater.”

Read more about the dissolved organic matter here.

Fohn Fjord in Greenland (Source:Flickr/Rita Willaert).

 

Modeling Dry-Snow Densification

From Geosciences“In the accumulation areas of ice sheets, ice caps, and glaciers, snow is deposited on the surface and, with time, becomes denser until it turns into ice. This process of densification proceeds at a rate that depends on climatic conditions; slowly in the cold, desert regions in the interior of the great polar ice sheets, and more rapidly in warmer regions with higher precipitation. The question of how to calculate this rate from given climatic information is an important aspect of many areas of glaciological research.”

Read more about the microscopic processes by which snow turns into ice on glaciers here.

A large iceberg had recently separated from the calving front of Antarctica’s Pine Island Glacier 2013 (Source: Flickr/U.S. Geological Survey).

 

Roundup: “Wild card” glaciers, luxury ice cubes, & glacial dynamics

This West Antarctica glacier is a ‘wild card’ for world’s coastlines

An edge of the Thwaites Ice Shelf.
An edge of the Thwaites Ice Shelf. Courtesy of Jim Yungel / NASA

“Scientists who have been raising alarms about the endangered ice sheet of West Antarctica say they’ve identified a key glacier that could pose the single most immediate threat to the world’s coastlines – and are pushing for an urgent new effort to study it. The glacier is not one that most Americans will have even heard of – Thwaites Glacier along the Amundsen Sea. It’s a monstrous body that is bigger than Pennsylvania and has discharged over 100 billion tons of ice each year in recent years.

The glacier is both vast and vulnerable, because its ocean base is exposed to warm water and because of an unusual set of geographic circumstances that mean that if it starts collapsing, there may be no end to the process. But it’s also difficult to study because of its location – not near any U.S. research base, and in an area known for treacherous weather. As a result, the researchers are also calling for more support from the federal government to make studying West Antarctica’s glaciers, and Thwaites in particular, a top priority.”

To read more about the Twhaites ice shelf, click here.

Luxury ice cubes? Greens slam ‘insane’ plan to carve Norway glacier

 

Courtesy of svaice.com  “A controversial plan to harvest ice cubes from a melting Norwegian glacier and sell them in luxury bars across the globe has drawn criticism from the head of WWF Norge, who said that such an idea proves the world has gone completely insane….
The idea to use parts of Svartisen – mainland Norway’s second largest glacier which is projected to melt over the next century – is being pushed forward by Norwegian company Svaice. In FebruarySvaice won a grant from the local Meloy municipality, which is enthusiastically backing the project and is due to meet on Wednesday to decide on the project’s future.”
Read more here.

Observed latitudinal variations in erosion as a function of glacier dynamics

UBC scientist Michele Koppes
UBC scientist Michele Koppes. Courtesy: Michele Koppes

“Climate change is causing more than just warmer oceans and erratic weather. According to scientists, it also has the capacity to alter the shape of the planet. In a five-year study published today in Nature, lead author Michele Koppes, assistant professor in the Department of Geography at the University of British Columbia, compared  in Patagonia and in the Antarctic Peninsula. She and her team found that glaciers in warmer Patagonia moved faster and caused more erosion than those in Antarctica, as warmer temperatures and melting ice helped lubricate the bed of the glaciers.

“We found that glaciers erode 100 to 1,000 times faster in Patagonia than they do in Antarctica,” said Koppes. “Antarctica is warming up, and as it moves to temperatures above 0 degrees Celsius, the glaciers are all going to start moving faster. We are already seeing that the ice sheets are starting to move faster and should become more erosive, digging deeper valleys and shedding more sediment into the oceans.”

To learn more about the study’s findings, click here.