NASA discovers massive hole melted away under Antarctic glacier

❝ A gigantic cavity – two-thirds the area of Manhattan and almost 1,000 feet (300 meters) tall – growing at the bottom of Thwaites Glacier in West Antarctica is one of several disturbing discoveries reported in a new NASA-led study of the disintegrating glacier. The findings highlight the need for detailed observations of Antarctic glaciers’ undersides in calculating how fast global sea levels will rise in response to climate change.

❝ Researchers expected to find some gaps between ice and bedrock at Thwaites’ bottom where ocean water could flow in and melt the glacier from below. The size and explosive growth rate of the newfound hole, however, surprised them. It’s big enough to have contained 14 billion tons of ice, and most of that ice melted over the last three years…

❝ About the size of Florida, Thwaites Glacier is currently responsible for approximately 4 percent of global sea level rise. It holds enough ice to raise the world ocean a little over 2 feet (65 centimeters) and backstops neighboring glaciers that would raise sea levels an additional 8 feet (2.4 meters) if all the ice were lost.

RTFA. Nice of the French and Germans to help us out with this research. Our government thinks we need more aircraft carriers and the beginnings of a whole new project to redesign rifles for the whole US Army.

Key West Antarctic glaciers already in runaway meltdown

Click to enlarge — Tongue of the Thwaites GlacierNASA/James Yungel

The collapse of glaciers along West Antarctica’s Amundsen Sea would raise seas by 1.2 metres.

Several of Antarctica’s most vulnerable glaciers have already begun a runaway meltdown, two new studies suggest. The work provides some of the first detailed forecasts on how quickly glaciers are likely to disappear from a region that has long concerned scientists.

One modeling paper finds that ongoing losses at the Thwaites Glacier have permanently destabilized that ice river, which drains into West Antarctica’s Amundsen Sea. The second study uses satellite radar observations to reveal that Thwaites and five neighbouring glaciers have nothing to hold them back from catastrophic collapse, leaving them more vulnerable than previously thought.

Were they all to melt, the six Amundsen Sea glaciers studied by Eric Rignot’s team contain enough water to raise global sea level by 1.2 metres. That process is likely to unfold slowly: at Thwaites alone, melting over the next century will probably cause sea levels to rise less than a quarter of a millimeter per year, or just 2.5 centimeters in total.

But that rate could speed up dramatically, to more than a millimeter per year, within two to nine centuries, says Ian Joughin, a glaciologist at the University of Washington in Seattle. “We are seeing the early stages of the collapse,” he says…

Thwaites is important because it flows from a broad, deep interior basin into the sea. Its vast storehouse of ice is big enough to contribute significantly to global sea level rise. The nearby Pine Island Glacier is retreating more quickly than Thwaites but drains only a very narrow trough.

The Joughin study “is a seminal paper,” says Andrew Shepherd, a cryosphere expert at the University of Leeds, UK. “It’s the first to really demonstrate what people have suspected, that Thwaites Glacier is a bigger threat to future sea level than Pine Island.”

Global sea levels are currently rising about 3 millimeters a year. Most of that comes from the thermal expansion of the warming oceans; some also comes from melting ice in Greenland and Antarctica.

“These systems, whether Greenland or Antarctica, are changing on faster time scales than we expected. We are kind of rediscovering that every day,” says Rignot.

It is the nature of scientific research to be conservative. Some may think discussions of events comprised of centuries instead of millennia still to be an exaggerated focus. Why talk about it if you ain’t about to live long enough to see it? That only demonstrates an absence of understanding of science and scientific goals. Everything in science tends to flow from the work that preceded whatever is current.

One important decision that needs to be made is allocation of funds and effort between the northern and southern hemispheres. The former tends to get the most attention because where the bulk of our species live. Sort of a silly reason; but, then, if we are anything it is irrational.

Thanks, Mike