Tiny dips in sea level reveal flow of climate-regulating underwater waterfalls

Beneath the surface of the Southern Ocean, vast volumes of cold, dense water plunge off the Antarctic continental shelf, cascading down underwater cliffs to the ocean floor thousands of metres below. These hidden waterfalls are a key part of the global ocean’s overturning circulation — a vast conveyor belt of currents that moves heat, carbon and nutrients around the world, helping to regulate Earth’s climate.

For decades, scientists have struggled to observe these underwater waterfalls of dense water around Antarctica. They occur in some of the most remote and stormy waters on the planet, often shrouded by sea ice and funnelled through narrow canyons that are easily missed by research ships.

But our new research shows that satellites, orbiting hundreds of kilometres above Earth, can detect these sub-sea falls.

By measuring tiny dips in sea level — just a few centimetres — we can now track the dense water cascades from space. This breakthrough lets us monitor the deepest branches of the ocean circulation, which are slowing down as Antarctic ice melts and surface waters warm.