Two weeks after scientists in the U.K. warned that a massive iceberg was “hours, days, or weeks” away from separating from Antarctica’s Larsen C ice shelf, it happened. One of the largest icebergs in recorded history broke free from Antarctica sometime between July 10 and 12, the product of a fast-moving crack in the ice shelf.

The “one trillion tonne” iceberg, likely to be named A68, is about the size of Delaware and contains enough water to fill Lake Erie twice, the researchers estimate. The scientists behind the Larsen C prediction are part of an Antarctic research group called Project MIDAS that investigates how global climate change impacts the ice shelf.

“Although this is a natural event, and we’re not aware of any link to human-induced climate change, this puts the ice shelf in a very vulnerable position,” said Martin O’Leary, a Swansea University glaciologist and member of the MIDAS project team, in a statement on the group’s website. “This is the furthest back that the ice front has been in recorded history. We’re going to be watching very carefully for signs that the rest of the shelf is becoming unstable.”

The worry is less about a new iceberg for sailors to avoid and more about the events that might come next. Researchers believe the recent split could trigger a collapse of the entire Larsen C ice shelf, a catastrophe that could potentially raise worldwide sea levels by four inches and in turn threaten the global economy. (Think: coastal assets.)

“In the ensuing months and years, the ice shelf could either gradually regrow, or may suffer further calving events which may eventually lead to collapse—opinions in the scientific community are divided,” said Adrian Luckman of Swansea University in a statement. “Our models say it will be less stable, but any future collapse remains years or decades away.”