Two new studies have been released that confirm glaciers in West Antarctica are in a state of “irreversible retreat.” Once these glaciers have thawed, they will cause average ocean levels to rise by four feet in the coming decades. Eric Rignot, lead author of NASA’s report on the subject, says, “It’s passed the point of no return.”
Six glaciers sit on the coast of West Antarctica: Pine Island, Thwaites, Haynes, Pope, Smith and Kohler. The structure of these glaciers is such that their leading edges float on the surface of the water, with their bodies receding down below to the bedrock of the continent. Where the glacier meets the bedrock, that place is called the grounding line. Warm water flowing into the Amundsen Sea has steadily eroded these grounding lines, causing the edges of the glaciers to extend further into the ocean and actually accelerating the melting process.
Radar confirms that there are no major mountain ranges below the vast sheets of ice. This is a problem because such geologic features could stop the flow of the glaciers once they’d melted past a certain point. Without mountains to stop them, the West Antarctica ice will simply continue to flow into the ocean; Rignot describes it as uncorking a full bottle of wine while it’s lying on its side.
Rignot’s study was conducted by scientists at NASA’s Jet Propulsion Laboratory and appears in Geophysical Research Letters. The University of Washington conducted a separate study on the Thwaites glacier that was published in the journal Science. The University of Washington’s study calculates that the collapse of the Thwaites glacier alone would cause global sea levels to rise 60 cm (1.96 feet). However, the “glacier also acts as a linchpin on the rest of the ice sheet, which contains enough ice to cause another three to four meters of sea level rise” (9-13 feet).
According to the NASA study, this erosion has been increasing for the last 40 years. “We do think this is related to climate warming,” says Rignot.