The ice shelf that scientists have been patiently watching has finally broken off into the ocean.
After months of anticipation, the Larsen C ice shelf finally broke off from Antarctica and is now adrift in the Southern Ocean, where it may drift off into warmer waters or stay in the area for decades. Scientists from Project MIDAS have actually been awaiting its break for several years, but for the last few months they have known that the ice shelf was on the verge of cracking off at any moment.
The crack in the Larsen C ice shelf has been growing rapidly for years and has grown popular amongst citizens because it’s easy to photograph and because the timing of it has contributed to political conversations. The ice shelf, which is 2,300 square miles and estimated to weight one trillion tons, has been preceded by Larsen A and Larsen B, which broke off in 1995 and 2002, respectively. The largest ice shelf to break off in modern history was known as B-15, from the Ross Ice Shelf, and measured about 4,200 square miles in 2000.
Larsen C is thought to have broken away sometime between July 10 to 12 and has been monitored by NASA’s Aqua MODIS satellite, which can produce images in thermal infrared at a resolution of 1 kilometer. Scientists were actually surprised at how long it took for the last few miles to crack, and said one month ago that the ice shelf was “hanging by a thread.”
“This event does not directly affect anyone, and repercussions, if there are any, will not be felt for years. However, it is a spectacular and enormous geographical event which has changed the landscape,” said Professor Adrian Luckman of Swansea University, lead investigator of the MIDAS project. “We will study the ice shelf for signs that it is reacting to the calving — but we do not expect anything much to happen for perhaps years. Icebergs are routinely monitored by various agencies, and they will be keen to keep track of this one.”
While the Earth’s changing climate has absolutely played a role in the rapid calving of ice shelves, these bodies of ice also go through periods of cracking and shedding, making it difficult to determine how much of it was caused by a rise in temperature. Luckman even said that there hasn’t been direct evidence that climate change impacted the shelf but that regional warming may have contributed to its retreated position.
If large fragments of Larsen C float into warmer waters and melts, scientists believe that it will not contribute to rising sea levels because it was already in the water and a part of the sea level. The iceberg does, however, pose a risk to mariners passing through the South Atlantic and the remnants of the crack are a threat to the entire glacier. If the remaining ice shelves also crack, those that are only attached to land and not already in the water would certainly cause a rise in the sea level.
For now, the ice shelf will naturally regrow if weather permits and any future collapse would be years or decades away because of how long it takes the hard ice to crack. There is similar movement on the Thwaites glacier in West Antarctica, which would result in disastrous consequences and could lead to a 6,000 foot high ice shelves collapsing into the water. Icebergs like this pose a serious threat to developed shorelines around the world. Just a few extra feet on shores could make a world of difference and the collapse of Thwaites threatens to add as much as 10 feet.
“If there is going to be a climate catastrophe, it’s probably going to start at Thwaites,” Ohio State glaciologist Ian Howat told Rolling Stone.