Between 1992 and 2017 we have observed a threefold increase in the rate of ice loss from West Antarctica, from 53 to 159 billion tonnes a year. About 3 trillion tons of Antarctica ice melted and elevated 7.6 mm of sea level in the past 25 years.
Antarctica is the largest ice sheet on Earth and nearly 220 billion tonnes of it is melting into the ocean each year.
Here & Now's Jeremy Hobson talks with Andrew Shepherd, professor of Earth observation at the University of Leeds and lead author of the study. "Under natural conditions, we don't expect the ice sheet to lose ice at all", continues Shepherd, "There are no other plausible signals to be driving this other than climate change". Using radar surveys and Landsat imagery, Dow reports direct evidence that a major 2016 calving event at Nansen Ice Shelf in the Ross Sea was the result of fracture driven by channels melted into the bottom of the ice shelf.
Recent work by Rob DeConto, the 2016 victor of the Tinker prize and professor of geosciences at the University of Massachusetts Amherst, includes findings in a 2016 paper also in Nature that highlights the potential for Antarctica to contribute much more sea level rise to the world's oceans than previously considered.
Whether Antarctic mass loss keeps worsening depends on choices made today, argues DeConto, who co-authored a separate paper in this week's Nature outlining two different visions for Antarctica's future in the year 2070.
"What happened roughly 10,000 years ago might not dictate where we're going in our carbon dioxide-enhanced world, where the oceans are rapidly warming in the Polar Regions", said Scherer. "Sea level rise for the future, it's not happening at the same rate in every part of the world... this gravity thing has a big impact".
Louisa Casson, of Greenpeace UK's Protect the Antarctic campaign, said: "Governments can take a historic step forward in October this year if they decide to create an Antarctic Ocean Sanctuary, protecting 1.8 million square kilometres in what would be the largest protected area on Earth. It's about half a degree Celsius warmer than the continent can withstand and it's melting about five metres of ice from its base each year, and that's what's triggering the sea-level contribution that we're seeing", he told BBC News. The melting is happening so fast that it could cause sea levels to rise 6 inches by the end of the century, the study projects. And what we're starting to see are the first signs of some of that ice starting to melt.
The two year study found that rising ocean and air temperatures are both destabilizing ice shelves from below and also causing them to crack on top, which ups the chance they might break off, according to a University of Waterloo press release published by Phys.org. From 1992 through 1997, Antarctica lost 49 billion tons of ice annually.
"This is like the "straw that broke the camel's back", triggering the runaway collapse of large areas of ice shelves weakened by pre-existing fracturing and decades of surface flooding".
The study used 20 years of data from 24 independent satellite measurements, along with studies from more than 80 co-authors, and was prepared in collaboration with NASA and ESA.
The study appears in the journal Nature.
If no one does anything to reduce the greenhouse gas emissions and the planet continues to warm then a scenario would come when a quarter of the volume of the sea ice would probably disappear by 2070, fishes and penguins will die and the U.S. could see $1 trillion in damage.