The vast glaciers of western Antarctica are rapidly melting and losing ice to the sea and almost certainly have “passed the point of no return,” according to new work by two separate teams of scientists.

The likely result: a rise in global sea levels of 4 feet or more in the coming centuries, says research made public Monday by scientists at the University of Washington, the University of California-Irvine and NASA’s Jet Propulsion Laboratory.

“It really is an amazingly distressing situation,” says Pennsylvania State University glaciologist Sridhar Anandakrishnan, who was not affiliated with either study. “This is a huge part of West Antarctica, and it seems to have been kicked over the edge.”

The researchers say the fate of the glaciers is almost certainly beyond hope.

One study shows that a river of ice called Thwaites Glacier is probably in the early stages of collapse. Total collapse is almost inevitable, the study shows.

A second study shows that a half-dozen glaciers are pouring ice into the sea at an ever-greater pace. That will trigger 4 feet of sea-level rise, says study author Eric Rignot, a glaciologist at the University of California-Irvine, and NASA’s Jet Propulsion Laboratory.

“The retreat of ice in that area is unstoppable,” Rignot said at a briefing Monday, adding that the glaciers have “passed the point of no return.”

In the summer of 2012, one of the most sensitive ecosystems on earth – the Greenland ice sheet – experienced a meltdown that alarmed scientists the world over. Greenland is an island encased in ice—by some measures, the world’s largest island, making icy Greenland a de facto “air conditioner” to the world. In 2012, many scientists said this air conditioner was broken. The evidence was in plain sight—on the ice sheet’s surface. Ninety-seven percent of the surface ice had melted. “Melting Point” is a re-examination of climate change debate—a story told by scientists who studies the shrinking of Greenland’s ice sheet, and by the Inuit people who lived through it.

In this special 45 minute report, which won the Silver World Medal in the Environment & Ecology category in the New York Festivals 2014 International TV & Film Awards Competition and 34th News & Documentary Emmy Awards Nomination, CCTV Senior Correspondent Sean Callebs takes us to Greenland, where the rapidly melting ice caps are a jarring reminder that global warming is not only real, but imminent.