Scientists at institutions in the United States and Australia on Friday published a set of unprecedented ocean observations near the largest glacier of the largest ice sheet in the world: Totten glacier, East Antarctica. And the result was a troubling confirmation of what scientists already feared – Totten is melting from below.

The measurements, sampling ocean temperatures in seas over a kilometer deep in some places right at the edge of Totten glacier’s floating ice shelf, affirmed that warm ocean water is flowing in towards the glacier at the rate of 220,000 cubic meters per second.

These waters, the paper asserts, are causing the ice shelf to lose between 63 and 80 billion tons of its mass to the ocean per year, and to lose about 32 feet of thickness annually, a reduction that has been previously noted based only on satellite measurements.

This matters because more of East Antarctica flows out towards the sea through the Totten glacier region than for any other glacier in the entirety of the East Antarctic ice sheet.

Its entire “catchment,” or the region of ice that slowly flows outward through Totten glacier and its ice shelf, is larger than California.

If all of this ice were to end up in the ocean somehow, seas would raise by about 11.5 feet.