Antarctica’s Southern Ocean Could Unleash a Century-Long “Heat Burp,” Scientists Warn

A vast and silent drama may be unfolding beneath the icy waters surrounding Antarctica. New research suggests that the Southern Ocean—one of the planet’s most powerful climate regulators—could someday release a massive pulse of stored heat, a “thermal burp” capable of reigniting global warming even after humanity successfully cuts emissions.

For decades, this ocean has acted like Earth’s safety valve, absorbing extraordinary amounts of excess heat and carbon dioxide produced by human activity. This buffering effect has slowed atmospheric warming and bought time for climate action. But scientists now warn that this hidden reservoir of heat may not stay locked away forever.

Climate-model simulations show that if the world eventually reduces atmospheric CO₂—first stabilizing emissions and then going “net negative”—the planet’s surface will begin to cool. As sea ice expands and surface waters grow colder and saltier, they become heavier and begin to sink. Meanwhile, the deep Southern Ocean remains comparatively warm. This imbalance sets up the conditions for deep-water convection: a sudden mixing event where warm water from the depths surges upward, releasing long-stored heat into the atmosphere.

Researchers describe this as a potential “century-long burp,” a slow but powerful exhalation of energy that had been quietly accumulating over decades. Such an event wouldn’t depend on future emissions—it would stem from the ocean’s memory of the past. In other words, the planet could experience renewed warming even in a world making significant climate progress.

What makes this scenario especially concerning is its longevity. Models indicate the heat release could continue for decades, perhaps up to a hundred years, creating a stubborn rebound effect that offsets gains made through emissions cuts. While the study relies on an idealized model and cannot assign exact timelines, experts agree it highlights a crucial vulnerability in Earth’s climate system: the deep ocean, still poorly understood, may hold surprises that complicate even the most ambitious mitigation plans.

This doesn’t negate the value of cutting emissions—far from it. The less heat the ocean stores today, the weaker any future release would be. But the findings underscore the need for long-term climate vigilance. Slowing emissions is essential; understanding the deep ocean is equally critical.

The Southern Ocean’s potential “heat burp” is a reminder that climate change is not just an atmospheric story. It is an ocean story, an ice story, and a story about the slow, powerful forces of the planet that may respond long after humanity shifts course.
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