The Larsen C Ice Shelf one of many segments along the Larsen Ice Shelf. It is located on the northwest part of the Weddle Sea, extending along the east coast of the Antarctic Peninsula from Cape Longing to the area just south of the Hearst Island.
Project MIDAS has been closely monitoring a crack in the Larsen C Ice Shelf for a number of years. It first observed the crack sometime in the second half of 2010. Ever since then, the crack has been getting longer and the rift, wider. Scientist predict that the crack would extend all the way across the ice shelf before this year ends. When this happens, the massive ice will calve and form one of the largest icebergs ever recorded. The total surface area of the calved ice will amount to more than 5000 KM2. Imagine an iceberg floating in the ocean that is 7 times the size of Singapore. The calving will cause the Larsen C Ice Shelf to lose about 10% of its total area.
In recent months, the rate at which the crack is extending has gotten faster. The crack has extended by around 27Km in the last 2 months alone. The iceberg is now perilously attached to the greater Larsen C Ice Shelf by a mere 20kM of ice.
According to satellite photos taken to monitor the crack, at certain areas, the rift seems to be as wide as 3Km. The rift where it’s at its widest is already filled with seawater and floating ice. You can see a time-lapse video of the rift getting wider.
The is not the first time that scientist have witnessed the disintegration of the Larsen Ice Shelf. Two smaller segments, namely the Larsen A and Larsen B were disintegrated in 1995 and 2002.
The good news is that the Larsen Ice Shelf holds a small proportion of ice compared to the entire Antarctic region. These calving and disintegration events, past and present, are not expected to significantly impact sea levels as these are natural processes where icebergs mainly originate. An ice shelf is basically a thick floating platform of ice where the ice sheet meets the sea. Like glaciers, they are ‘ice rivers’ where huge hunks of ice make their way down a slope slowly until it meets the sea. However, these massive disintegration events are part of the large picture of global climate change. Increasing local temperatures in the Antarctic could make these disintegration events larger and more significant. Ice shelves are actually important as it serves as a bulwark against the encroaching sea. Without it, the warmer water from the ocean would accelerate the melting process of land based ice.
- Project Midas, tracking the large rift on the Larsen C Ice Shelf. http://www.projectmidas.org/
- Carbon Brief article on the Larsen C Ice Shelf. https://www.carbonbrief.org/discovery-exposes-fragility-of-antarcticas-larsen-c-ice-shelf
- Additional images from NASA Earth Observatory. http://earthobservatory.nasa.gov/IOTD/view.php?id=89257
- Images of the Larsen C Ice Shelf crack from the sky. http://visibleearth.nasa.gov/view.php?id=89257