Iceberg B-15 melting away

Iceberg B-15 first sparked concern among climate scientists in March 2000, when it broke away from Antarctica’s Ross Ice Shelf and became the largest iceberg ever recorded. After 18 years of rapid melting, the latest satellite images from NASA confirm that the once-icy behemoth’s days are numbered.

When B-15 first went solo from the Antarctic, it measured 160 nautical miles long and 20 nautical miles wide, or roughly the size of Connecticut. However, satellite images taken from the International Space Station (ISS) on May 22 reveal that it’s now just 10 nautical miles long and five nautical miles wide.

On Wednesday, NASA published the latest images of B-15 sporting a large fracture visible along its center, suggesting that more breakages are imminent. Not only are smaller bergs breaking off and melting, but B-15 is now on a crash course for the equator, where the melting process is about to pick up more speed.

Iceberg B-15 melting away
Iceberg B-15 melting away

“They tend to pond with water, which then works its way through the iceberg like a set of knives,” NASA glaciologist Kelly Brunt said of its multiple fissures. An iceberg needs to be at least 20 nautical miles to be tracked by the National Ice Center. Just four pieces of B-15’s former self still meet that size requirement, while the rest of its fractured pieces have either disappeared entirely or have melted to the point that they are untraceable.

An earlier image of B-15Z, the largest remaining piece of B-15’s former self, from October 2017 showed the iceberg off the tip of the Antarctic Peninsula, meaning it had traveled about three-quarters around the Antarctic from its original location. When coastal currents prevented B-15Z from moving into the Drake Passage, it headed north to the southern part of the Atlantic Ocean, meaning its on a crash course for the equator.

Iceberg B-15Z's ominous path
Iceberg B-15Z's ominous path

As of last month, the berg was about 150 nautical miles northwest of the South Georgia islands. “Icebergs that make it this far have been known to rapidly melt and end their life cycles here,” NASA’s Kathryn Hansen explained. With South America to the west of the moving iceberg, B-15Z is charging into warmer Atlantic waters meaning it’s not long for this ocean.

Whereas it only took 18 years for B-15 to meet its end, the loss of a standard iceberg from the Antarctic ice shelf would normally take as long as 50 to 100 years to replace. Climate change and this year’s spike in ocean temperatures suggest that B-15 won’t be the only loss from Antarctica this year.

Photos via NASA Earth Observatory