Antarctic sea ice dwindled to a record-low this February, shrinking below 772,000 square miles. In a study released last week, researchers explain why: a combination of La Niña conditions and human-caused climate change has done a number on Antarctica’s sea ice.

Why This Matters

When satellites began recording Antarctic sea ice in 1970, it was expanding. But in 2014, ice caps started to drop, hitting an all-time low in 2017, coming back a bit in 2020, then falling again in 2022 to a record low. Scientists have long been puzzled by this. Global warming has had a clear effect on sea ice in the Arctic, but climate change’s effects on the Antarctic have been harder to pin down since it is more subject to natural climate patterns. Still, these natural climate patterns cannot explain the extreme nature of Antarctic melting -- climate change has contributed to temperatures rising in the region to as much as 70 degrees above normal, an unprecedented and sobering finding.

A Combination Of Factors At Play

A natural weather pattern, the Amundsen Sea Low (ASL), contributed to this startling lack of sea ice. The ASL is a kind of never-ending hurricane off the coast of West Antarctica, and if strengthened by La Niña or intense winds, it can devastate the region’s sea ice.

Meanwhile, oceans warmed to record high temperatures in 2021, melting ice from below the surface and making it much easier for the ice to break during summer. Without the cover of ice, the ocean’s surface gains greater exposure to sunlight, warming even more, and creating a vicious cycle.