The West Antarctic Ice Sheet , a massive system of glaciers, is collapsing as a result of glacier melting (global warming). The process is most likely irreversible and cause a global sea lever rise of at least 10 feet, a pair of independent studies conclude.
A warmer planet gives way to rising oceans
Previously, the two-mile-thick (3.2 kilometers) glacier system was thought to last for at least a couple thousand years in the future, but new research reports faster melting times and more rapid displacement of ice into the ocean. Namely, NASA researchers found after shifting through 40 years worth of observational data that six big glaciers in the Amundsen Sea “have passed the point of no return.”
The glaciers contain enough ice to raise global sea level by 4 feet (1.2 meters) and are melting faster than most scientists had expected, which will require adjusting estimates of sea-level rise. Their disappearance will most likely destabilize other sectors of the ice sheet, so the ultimate rise could be triple that.
“This retreat will have major implications for sea-level rise worldwide,” said Eric Rignot, a UC-Irvine Earth science professor and lead author of a study to be published in a journal of the American Geophysical Union.
Another study made by a separate team led by Ian Joughin of the University of Washington studied one of the most important glaciers, Thwaites, using sophisticated computer modeling. The findings, expected to be published on May 16 in the journal Science, suggests that the Thwaites Glacier, a relatively fast-moving part of the ice sheet, will likely melt away into the ocean within several centuries, enough by itself to raise sea levels 2 feet.
Both studies seem to be conclude what world famous glaciologist John H. Mercer of the Ohio State University predicted way back in 1978: the rapid human-driven release of greenhouse gases pose a great threat to West Antarctic ice sheet, which is particularly vulnerable to such interventions.
Yet, this will happen in hundreds of years
These news are extremely startling since they mean that we have to prepare for a worse sea level rise scenario than initially thought, which could displace hundreds of millions living on the world’s coastlines. You shouldn’t panic though. Collapse is a term that in our minds is associated with an event that will happen very soon in the near future. In fact, these glaciers will retreat in about two hundred years, although estimates are yet to be fully refined. In a geological time frame, however, this is equivalent to a very sudden, unnatural event indeed.
Another, separate study that studied West Antarctic ice melt was released on Monday and reached the same conclusion: the major glacial system in the region that was previously thought stable is collapsing.
“What we have shown is this glacier is really in the early stages of collapse,” says Joughin, lead author of a study published separately in the journal Science on Monday.
Richard Alley, a professor of Earth sciences at Penn State University in State College, Pennsylvania, who was not involved in either research project, says both are important. The data from Rignot’s group is consistent with the computer modeling by Joughin’s group, he says. Next, however, both works need to be confirmed by other independent models.
“But these results are sobering,” he says, “even the possibility that we have already committed to three-plus meters of sea-level rise from West Antarctica will be disquieting to many people, even if the rise waits centuries before arriving.”
It’s important to note that much of Antarctica’s ice sheet is in fact a system. As such, once the six glaciers near the coast melt, it is possible that the rest of the ice in West Antarctica could eventually follow like a domino string as a result of mechanical failure.
Joughin says that the collapse of the Thwaites glacier in particular could endanger much of the rest of the huge West Antarctic Ice Sheet, since the systems are connected.
“Imagine trying to take out part of a building and expecting the other half to keep on standing,” he says.