The calving of a Delaware-sized iceberg (A68) from Antarctica’s Larsen C ice shelf on July 12, 2017 visualized climate change’s dramatic impacts on Earth’s ice sheets.
The Break
A68, one of the largest icebergs ever recorded, measured 2,240 square miles (5,800 km²) and weighed a trillion tons. It separated from Larsen C along a rift that had grown for years. Satellite imagery captured the moment - a clean break creating a new coastline.
The Larsen Legacy
Larsen A collapsed in 1995. Larsen B, thought stable for 10,000 years, disintegrated in 2002 in just six weeks - 1,250 square miles gone. Larsen C’s calving raised fears it would follow, though scientists noted A68’s break was likely natural calving, not climate-driven collapse.
Sea Level Implications
Ice shelves float, so their melting doesn’t directly raise sea levels (like ice cubes in a glass). But they buttress land-based glaciers - without shelves, glaciers accelerate into the ocean. Larsen B’s collapse tripled glacier flow rates. If Larsen C fully collapses, it could destabilize the Antarctic Peninsula.
A68’s Journey
The iceberg drifted north for three years, breaking into fragments. By 2020, it threatened South Georgia Island’s ecosystem - grounding could block penguin and seal foraging routes. It narrowly missed, eventually fragmenting into dozens of smaller bergs.
Antarctic Tipping Point
The Antarctic Peninsula is one of Earth’s fastest-warming regions (+3°C since 1950s). Between 1995 and 2017, seven ice shelves collapsed or retreated. The Ross Ice Shelf and Thwaites Glacier (“Doomsday Glacier”) now show concerning instability. Thwaites alone could raise sea levels by 2 feet.