Updated January 20, 2023 at 4:20 p.m. EST|Published January 20, 2023 at 6:00 a.m. ESTComment on this storyCommentGift ArticleThis is a story about a curious seal, a wayward robot and a gigantic climate change disaster that may be waiting to happen.Scientists tagged a southern elephant seal on the island of Kerguelen, an extraordinarily remote spot in the far southern Indian Ocean, in 2011. The seal was a male close to 11 feet long weighing nearly 1,800 pounds, and they fitted his head with an ocean sensor, a device that these massive seals barely notice but that have proved vital to scientific research.
Kerguelen
Islands
Indian Ocean
Return from Antarctica in Sep. 2011
Trip to
Antarctica in Jan. 2011
Denman
glacier
ANTARCTICA
Totten
glacier
Source: MEOP/SNO-MEMO
Kerguelen Islands
Return from Antarctica, in Sep. 2011
Seal’s trip to Denman glacier in Jan. 2011
Indian Ocean
Denman
glacier
Amery
Ice Shelf
Totten
glacier
ANTARCTICA
Source: MEOP/SNO-MEMO
Kerguelen Islands
Indian Ocean
Return from Antarctica, in Sep. 2011
Seal’s trip to Denman glacier in Jan. 2011
Denman
glacier
Amery
Ice Shelf
Totten glacier
ANTARCTICA
Source: MEOP/SNO-MEMO
Kerguelen Islands
Indian Ocean
Return from Antarctica, in Sep. 2011
Seal’s trip to Denman glacier in Jan. 2011
Denman
glacier
Amery
Ice Shelf
Totten glacier
ANTARCTICA
Source: MEOP/SNO-MEMO
Elephant seals like this one swim more than 1,500 miles south from Kerguelen to Antarctica, where they often forage on the sea floor, diving to depths that can exceed a mile below the surface. As summer in the Southern Hemisphere peaked, the seal made a standard Antarctic journey, but then went in an unusual direction.In March 2011, he appeared just offshore from a vast oceanfront glacier called Denman, where elephant seals are not generally known to go. He dove into a deep trough in the ocean bed, roughly half a mile below the surface. And that is when something striking happened: He provided an early bit of evidence that Denman Glacier could be a major threat to global coastlines.AdvertisementThe seal swam through unusually warm water, just below the freezing point, but in the Antarctic, that is warm. Given its salt content and the extreme depths and pressures involved — in some regions Denman Glacier rests on a seafloor that is over a mile deep — such warm water can destroy large amounts of ice. And it certainly could have been doing so at Denman.Yet scientists do not appear to have seen the significance of the seal data. Back then, Denman had not received much scientific attention. It did not help that the glacier is extraordinarily difficult to study directly. It lies between the two Antarctic research bases of Australia. The logistics are challenging for a voyage from either side, especially as the glacier is often locked in by extensive sea ice.Researchers had already observed that the glacier was losing some of its mass, which is a worrying sign. They also knew something else: Denman serves as potential doorway into a region of extremely deep and thick ice, even for Antarctica.With Denman and several other neighboring glaciers in place, the doorway remains closed. Opening it would allow warmer ocean water to start eating away at this thick ice, leading to gradual melt and eventually, a massive influx of new water into the ocean. That would have the potential to unleash over 15 feet of sea level rise, remaking every coastline in the world. So the scientists flew a few planes over Denman and watched with their satellites. And they waited.A striking discovery came in 2019. Using satellite data and other techniques, scientists publish …