There have been plenty of talks about rising temperatures causing ice to fall off in Antarctica, but a recent chunk of ice that’s gone missing is baffling scientists. The hole didn’t appear on the edge of the ice, but rather toward the center, leaving a hole the size of the state of Maine, scientists say.
Kent Moore of the University of Toronto Mississauga said “It looks like you just punched a hole in the ice.” Moore and other scientists know the name of this phenomenon, but aren’t quite sure how it happens. It’s known as a polynya, and are typically spotted close to the coastline in Antarctica. However, “This is hundreds of kilometers from the ice edge. If we didn’t have a satellite, we wouldn’t know it was there,” Moore explained.
Scientists had found a polynya in the same area a few decades ago, and now the hole has opened twice in just as many years. “At that time, the scientific community had just launched the first satellites that provided images of the sea-ice cover from space,” Moore said, allowing scientists to have better access to notice this phenomenon.
Upon hearing this news, the fact that the hole has opened up twice recently without happening for nearly 40 years, many were quick to blame climate change. Moore says, however, that climate change shouldn’t be blamed for this phenomenon, calling those accusations “premature.” He added that “Once the sea ice melts back, you have this huge temperature contrast between the ocean and the atmosphere. It can start driving convection, which can keep the polynya open once it starts.”
Recent satellite images of Antarctica have also found that the continent has created an “upside-down ice canyon.” This is happening along the Dotson Ice Shelf, leaving some to believe that the shelf would break off within 50 years despite predictions of 200 years. Noel Gourmelen of the University of Edinburgh says this other phenomenon isn’t a big concern just yet. “That is unlikely to happen because the ice will respond in some way to the imbalance.”
He added that “It’s possible the area of thinning could widen or the flow of ice could change. Both would affect the rate at which the channel forms…But the important point here is that Dotson is not a flat slab and it can be much thinner in places than we think it is and much closer to a stage where it might experience major change.”
Scientists warn that if Dotson were to fall off into the ocean, the Kohler and Smith Ice Shelves would also dump into the ocean, causing a global rise in sea-level. Research has shown that the surface on the Dotson Ice Shelf is lowering by just over 10 inches per year, resulting in an overall thinning of more than eight feet per year in the ice shelf that’s currently over 1,300 feet thick.
While polynyas weren’t found to be a direct effect of rising temperatures, scientists say that the inverted canyon in Antarctica is likely a result of rising water temperatures. “We say warm; it’s 0.6-0.7 degrees,” Gourmelen said. “It makes its way into the cavity under the shelf along a trough to the grounding line, and then it starts to rotate clockwise and rises. And it comes out on the west side. That’s where we see the thinning and basal melt.”
Satellite images of Antarctica say that the front of the Dotson Ice Shelf could melt all the way through within 20 years. Professor Andy Shepherd of Leeds University says “An ice shelf can be a complicated thing. As you thin them it reduces the traction on the feeding glaciers, allowing those glaciers to speed up; and as they speed up, they should put more ice into the ice shelf so that it thickens again. It is supposed to be a stabilizing effect.”
Researchers are able to find out a lot more these days about why Antarctica is having the types of phenomenons that it’s currently experiencing. Moore said “Compared to 40 years ago, the amount of data we have is amazing.” This even includes potentially finding ecosystems within Antarctica, as the area that’s been lost in the Larsen C Ice Shelf is being studied.
Scientists believe that there’s now an area that had been hidden for more than 100,000 years, and could reveal lost species. In recent years, researchers have been studying areas that have melted in Antarctica, and have found “pioneers species, which slowly colonize the sea.” It will be interesting to see what’s found on the newest expedition as scientists rush to discover more about Antarctica.