Scientists believe they’ve discovered why Antarctica’s ice is melting so fast.
They say stronger ocean currents beneath West Antarctica’s Pine Island Glacier Ice Shelf are eroding the ice from below.
Last week, we told you about a recent study noting that sea levels have risen at the fastest rate in more than two millennia. Among the contributing factors to this rise in sea levels is the melting polar ice, especially in Antarctica.
Although global warming is seen as the chief culprit, the study released this week sheds more light on glacial melting.
The researchers noticed the erosion after discovering a rapidly-growing cavity, which has formed beneath the ice shelf and is allowing more warm water to melt it.
According to the study, the glacier is sliding into the sea at a rate of four kilometers (2.5 miles) a year, while its ice shelf is melting at about 80 cubic kilometers annually. That’s about 50 percent faster than it was in the early 1990s.
One day, while on an expedition in the Antarctic, researchers observed the strength of the melting process as they watched ice cold, seawater appear to boil on the surface.
That observation suggests that deep colder water, boosted by added water from the fresh glacial melt, rose to the surface in a process called upwelling, says study lead author Stan Jacobs, an oceanographer at Columbia University’s Lamont-Doherty Earth Observatory.
Upwelling can be described as an oceanographic phenomenon where warmer surface water replaces colder deep water and vice-versa.
Researchers have found evidence over the past several decades that Antarctica is getting windier, which may also help explain the changes in ocean circulation.
Dr. Jacobs says that stronger circumpolar winds would tend to push sea ice and surface water north, which would then allow more warm water from the deep ocean to upwell onto the Amundsen Sea’s continental shelf and into its ice shelf cavities.
Over the past decade or so, there’s been growing concern over the impact of rising sea levels, especially since most of the world’s population lives in coastal regions. Millions of people are threatened with the possible consequences of high sea levels, such as an increasing number of floods.