Stanford Study Resolves Decades-Long Mystery of Antarctic Sea Ice Growth and Abrupt 2016 Collapse

New research explains why Antarctic sea ice grew for decades before a sudden 2016 collapse caused by trapped subsurface heat and wind-driven upwelling.

By: AXL Media

Published: Mar 28, 2026, 10:54 AM EDT

Source: Information for this report was sourced from Stanford University

The Paradox of Expanding Ice in a Warming World

For nearly four decades, the behavior of Antarctic sea ice remained one of the most persistent enigmas in climate science. While global temperatures climbed and Arctic ice plummeted, the ice surrounding the southern continent unexpectedly expanded from the 1970s through 2015. This phenomenon often contradicted standard climate models, which predicted a steady decline. However, a new study published in the Proceedings of the National Academy of Sciences has finally traced the mechanisms behind this growth and the subsequent, catastrophic retreat that began in 2016. Led by Assistant Professor Earle Wilson, the research highlights how the Southern Ocean acted as a massive heat reservoir, hidden beneath a temporary lid of freshwater.

The Role of the Freshwater Salinity Lid

The key to the decades-long expansion was a surge in precipitation, including both snow and rain, which created a "lid" of less salty, lower-density water on the ocean's surface. According to the Stanford team, this stratification effectively partitioned the water column, preventing the frigid surface from mixing with the warmer, denser water trapped several hundred meters below. This deeper layer, which can be two to three degrees warmer than the surface, was held in check by the freshwater barrier. As long as the "precipitation effect" outweighed other factors, the surface remained cold enough for sea ice to continue its anomalous growth despite a warming atmosphere.

Unleashing the Subsurface Heat Reservoir

The equilibrium between the cold surface and the warm interior was eventually shattered by an increase in stormy weather and shifting wind patterns. These winds drove a process known as upwelling, which forces deeper, warmer water toward the surface. While upwelling had been increasing in concert with precipitation for years, it finally reached a tipping point in 2016. Professor Wilson describes this as a race where "precipitation was winning until upwelling took over." Once the warm water breached the salinity lid, it unleashed decades of accumulated thermal energy, causing sea ice extent to plummet to record lows from which it has not yet recovered.