A one trillion ton iceberg is on the move. A68, as it’s known, broke off the Larsen C ice shelf in Antarctica last July, but it didn’t stray too far from the coast for a year. In the past two months it has spun off, however, making a 90-degree turn into the Weddell Sea.
“It has a spectacular amount of momentum and it’s not going to stopped easily,” oceanographer Mark Brandon wrote on his website. “I should think we will see some interesting collisions with the ice shelf in the next few months.”
A68 is bigger than Delaware and is made up of enough water to fill Lake Erie twice. It’s the sixth-largest iceberg ever recorded.
The momentum may continue to move A68 north into warmer waters, and the prospect of a huge iceberg in a major shipping lane is worrisome. The Drake Passage, the 600-mile gap between South America’s Cape Horn and Antarctica’s South Shetland Islands, is one of the world’s roughest seas. And it sees a lot of international shipping traffic: Any post-Panamax ships that are too big to get through the Panama Canal have to go around Cape Horn.
But a more likely problem is more Antarctic ice melting. Brandon reports it was almost 20°C (68°F) warmer than the mean temperature over the Weddell Sea and Larsen Ice shelf this year. Researchers say if the entire Larsen C ice shelf were to collapse, it would be a catastrophe that could raise worldwide sea levels by 4 inches, threatening the global economy.