Satellite images show that the world’s largest iceberg has disappeared

The once-largest iceberg in the world is currently unobservable from satellites after it has melted into small pieces.
A68 is the largest one-time iceberg in the world, with an area of ​​6,000 square kilometers when it broke off Antarctica in 2017. A68’s area is larger than 32 other countries, according to the report. BBC .

But recent satellite images show that the giant iceberg A68 has disappeared. According to the American Center for Snow and Ice Research, the A68 has broken into many small pieces and no longer needs follow-up. Disappeared from satellite imagery The A68 was originally part of the Larson C ice shelf, at the edge of Antarctica near South America. When it was separated from Larson C in July 2017, this iceberg barely moved much during a year. After that, the A68 began to drift north at an increasing speed, due to the impact of strong currents and sea winds. The journey of an iceberg weighing billions of tons is similar to many other icebergs. It spins out of Antarctica, drifting into the South Atlantic, toward South Georgia, a British overseas territory. South Georgia is where countless icebergs have targeted and completely disappeared. Trapped in shallow seas, these glaciers inevitably melt away. The A68 iceberg once had the largest area in the world. Photo: CPL PHIL DYE RAF / CROWN. But the A68 is different. The fate of the once largest iceberg in the world was determined by the waves, warm water and high temperatures in the South Atlantic. Instead of completely melting, the A68 broke into smaller pieces of ice. “Amazingly, the A68 has been around for so long,” said Andrian Luckman, a scientist from the University of Swansea, UK. Although thousands of square kilometers wide, the A68 iceberg has only an average thickness of about 230 meters, making it described as a “A4 paper floating in the ocean”. “This iceberg is extremely fragile when it moves across the ocean. The A68 has been around for many years, it eventually breaks into 4-5 fragments. But this fragment then continues to break apart,” Luckman said. The American Snow and Ice Research Center is an agency recognized by the international community for its function to track and name icebergs that pose a threat to shipping. The icebergs listed in the US Snow Research Center’s list must have a minimum length of 18.5 km, or a total area of ​​at least 68.5 km2. Right now, not a single piece of fragment from the A68 qualifies for the size to be listed on the list of icebergs. The largest piece, named A68a, measured on April 16 has only two dimensions of 5.4 km and 3.6 km, respectively. Scientists say? A68 once became famous globally when it first appeared, this iceberg was the star on social networks. People around the world share satellite imagery of this iceberg, especially as the A68 floats toward the South Georgia island. When colliding with this island, the A68 ice disrupted the lives of thousands of penguins in South Georgia, creating news that attracted the attention of the world public. But not only for entertainment meaning, A68 is the serious research subject of the scientific community. The origin of this glacier, the Larsen C ice shelf, is a giant iceberg, formed from two glaciers. Larsen C broke off land and slid into the ocean. The A68a is the largest remaining fragment. In the photo, A68a next to the previously melted ice sheet. Source: BBC. A68’s fate helps scientists better understand the formation of ice shelves like Larsen C, as well as the reason they break up, creating icebergs. “One scientific result to mention is what we have learned about faults where terrestrial glaciers meet, creating floating ice shelves,” says Christopher Shuman, an expert at the University of Maryland. , said. “Since we have new sensors, we can observe the rupture progressing more often, which was not observable in decades ago,” added Mr. Shuman. Most researchers consider A68 to be the product of a very natural process. The ice shelves will maintain balance. The release of glaciers is a way for them to balance the amount of snow absorbed, as well as the amount of snow and ice received from the Antarctic glaciers. However, scientists acknowledge that A68 is indeed an example of processes that help people realize that global warming can destroy the icy structures on Earth. One such process is called “hydraulic shearing”. In the process, warming produces melted water on the surface, which then fills the cracks and holes, causing the cracks to widen and erode into the core of the iceberg. During the A68’s last existence, hydraulic shearing resulted in large chunks of ice being shredded overnight. “This is another example of how icebergs change, showing that ice shelves can collapse quickly as the world gets warmer,” said Ted Scambos, an expert at the University of Colorado.