In an unexpected shift, East Antarctica gained 695 billion tons of ice between 2021 and 2023, briefly slowing the continent’s long-term decline. A study published in Nature reveals the surprising cause: ocean warming thousands of miles away in the tropics.
How Tropical Heat Triggered Antarctic Snow
Between 2021 and 2023, sustained warming in the "tropical warm pool" (where the western Pacific meets the eastern Indian Ocean) set off a domino effect:
- Atmospheric Wave: The tropical heat launched a large-scale atmospheric disturbance (a Rossby wave train) toward the South Pole.
- Pressure Dipole: This established a low-pressure zone south of Australia alongside high pressure over East Antarctica.
- Atmospheric Rivers: The pressure setup funneled moist air via atmospheric rivers from the Indian Ocean straight to East Antarctica, triggering massive snowfall in regions like Queen Mary Land and Wilkes Land.
Researchers noted that human-driven climate change accounted for only 9% of the snowfall anomaly. Instead, natural multi-year tropical warmings act as a remote "regulator" for East Antarctic snow.
Antarctica Is Still Melting
Scientists emphasize that this two-year gain is a temporary surge, not a reversal of climate trends:
- Long-Term Loss: Antarctica has lost an average of 140.5 billion tons of ice per year over the past two decades.
- Ongoing Vulnerability: West Antarctica continues to lose mass rapidly, while warm ocean currents melt East Antarctic ice shelves from below.
While tropical ocean patterns can temporarily boost snowfall, they won't halt the overall decline of polar ice sheets.
