evidence: Between 1992 and 2017, Antarctica lost more than three trillion tons of ice, most of which came from the West Antarctica Ice Sheet. Some of the most dramatic impacts of warming are collapsing ice shelves in West Antarctica, which are caused by warming. The animation at the left shows the historic breakup of the Larsen B Ice Shelf. Ice shelves are like bookends that support ice sheets and glaciers, helping them stay on land. When an ice shelf collapses into the ocean, the glaciers that it held in place begin to slide into the sea at an accelerated rate. [...] Since the late 1980s, a number of Antarctic ice shelves have collapsed or retreated. While the West Antarctic Ice Sheet suffered some of the largest early losses, the East Antarctic Ice Sheet is being affected as well. In late March 2022, the 1,191 square mile Conger Ice Shelf (about the size of Los Angeles) collapsed, shortly after a surge of warm air resulted in temperatures that were a record 40°C (72°F) above normal. [...] In total, parts of 21 ice shelves on the Antarctica Peninsula broke apart between 2000 and 2020. At sustained warming levels between 2°C and 3°C, the West Antarctic Ice Sheet will be lost almost completely and irreversibly over thousands of years.