The massive Pine Island Glacier on Antarctica, which is one of the continent’s fastest melting glaciers, is giving climate experts additional cause for concern.
Its ice shelf, a frozen ledge at the edge of the Pine Island Glacier, is the source of the problem. The ice shelf aids in the stabilization and containment of the massive ice flow behind it.
However, it is now disintegrating into shards.
More than a quarter of the ice shelf has broken away in the shape of massive icebergs that crash into the ocean and drift away in the last five years alone.
At the same time, the glacier has begun to lose ice more quickly. The speed of ice pouring from the glacier into the sea has increased by 12% since 2017.
A new study published in the journal Science Advances on Friday summarises these losses.
According to main study author Ian Joughin, a glaciologist at the University of Washington, the key question is what will happen next. There’s a chance that the ice shelf may stable and the ice flow will slow down, or at the very least stop.
“The alternative option is that this process will continue and the shelf would come apart much faster than we expected,” he told E&E News.
The Antarctic ice sheet’s Pine Island Glacier is a behemoth. According to studies, the glacier, which is located near the Amundsen Sea on the edge of West Antarctica, is dumping approximately 60 billion tonnes of ice into the ocean each year. Since at least the 1970s, their losses have been increasing.
According to Joughin, the ice shelf at the glacier’s edge—a form of floating ice ledge that juts out into the sea—is analogous to a cork in a bottle. It aids in the halting of the flow of ice pressing against it from behind. The weaker the cork becomes, the more ice melts and flows into the ocean, contributing to global sea-level rise.
Pine Island Glacier had already caused concern among scientists. Warm ocean waters seeping through the ice have caused the ice shelf to thaw in recent years, causing it to melt from the bottom up.
Warm waters melting the ice from below has become an increasing hazard for glaciers along West Antarctica’s coast (Climatewire, April 10, 2018). Warm currents rising from the deep sea near the Antarctic coast appear to be the source of the water. Experts believe that altering wind patterns in the Southern Hemisphere, which are likely influenced by climate change, is assisting in driving warm currents up to the ice’s edge.
According to the researchers, when Pine Island’s ice shelf decreased and deteriorated, the ice flow began to accelerate in “fits and starts.” It would accelerate quickly, then slow down for a few years. The ice flow was largely steady between 2009 and 2017.
That began to change approximately five years ago when the ice shelf began to regularly drop icebergs, some of which were several kilometers long. Last year, a chunk of the glacier the size of Washington, D.C. was lost.
The experts believe that the glacier’s flow has been uneven over the last few decades, which is at least partly to blame. Cracks and rifts appeared on the ice over time. Beginning in 2017, the shelf began to deteriorate fast.
For the time being, scientists are unsure if the shelf will continue to crumble at the same rate as it has in recent years. Joughin claims that simulating the process in models is quite challenging.
Satellites, fortunately, are assisting scientists in keeping a close eye on the glacier. Every six days, the European Space Agency produces new photos of the site.
If the shelf continues to deteriorate, the ice flow might accelerate much more significantly, even doubling or tripling, according to Joughin. Pine Island Glacier already contributes more than a fourth of Antarctica’s contributions to sea-level rise during the previous few decades, making this a frightening potential.
However, there is still too much uncertainty to predict whether or not that situation is likely.
“It’s a bit of a long shot that the shelf will break apart, but it’s not a huge long shot,” Joughin added. “I don’t want to make a bold forecast about what will happen.”