Scientists remain concerned that the break could destabilize the remaining Larsen C ice shelf.
By Eric Roston
An iceberg holding twice as much water as Lake Erie has broken off from Antarctica. The world’s biggest ice cube weighs a trillion metric tons and has a surface area the size of Delaware.
It sounds scary, but it’s not as terrifying as it sounds. The mass of ice was always floating—it’s the freely floating element that’s new. The iceberg jettisoned off the Larsen C ice shelf, a layer of ice atop the Weddell Sea that ranges in thickness from 200 meters to 600 meters. Scientists will continue to study the area for signs of further collapse.
Because ice shelves already float on open water, the icebergs they produce don’t affect global sea levels, which are rising at a rate of about 3.4 millimeters a year. The oceans are swelling, both directly and indirectly, due to human-induced rising temperatures. Warmer water takes up a greater volume than the same amount of cold water, contributing to the expansion. While the new ice behemoth will melt into water and consequently warm over time, it will not make a significant contribution to the overall heating of the world’s oceans. Of greater concern are melting ice sheets and glaciers pouring water into the sea that, unlike ice shelves, haven’t been a part of it before.
A rift across the Larsen C Ice Shelf in the Antarctic Peninsula in Aug. 2016.
Photographer: John Sonntag/NASA
“Although this is a natural event, and we’re not aware of any link to human-induced climate change,” said Martin O’Leary, a glaciologist at Swansea University, in a statement, “this puts the ice shelf in a very vulnerable position. This is the furthest back that the ice front has been in recorded history.”
Whether scientists can directly tie the iceberg calving to human activity has no bearing on the long-term trend, which reveals that climate pollution is warming the Earth.