An Enormous Iceberg Is Threatening to Break Off Antarctica’s Pine Island Glacier

An Enormous Iceberg Is Threatening to Break Off Antarctica’s Pine Island Glacier

SOURCE: Science Alert DATE: October 10, 2018 SNIP: Antarctica’s Pine Island glacier could soon lose another massive chunk of ice, with signs of a 30 kilometre (19 mile) long crack appearing along its surface. Only a year ago a 260 square kilometre (100 square mile) iceberg split free from the glacier – the fifth large calving event this century. That makes this one a potential number six, reflecting an alarming trend that could eventually have an impact on rising sea levels. There are still roughly 10 kilometres of ice connecting the prospective iceberg to the end of the glacier; once that breaks free in the coming weeks or months, it will be a monstrous 300 square kilometre (115 square mile) island adrift in the Antarctic’s oceans. These types of iceberg calvings are also starting to happen more often than we’d expect, in line with a rise in the rate of melting ice in West...
Climate change kills Antarctica’s ancient moss beds

Climate change kills Antarctica’s ancient moss beds

SOURCE: BBC DATE: September 25, 2018 SNIP: Emerging from the ice for a brief growing season every Antarctic summer, the lush green mosses of East Antarctica are finally succumbing to climate change. That is according to a study of the small, ancient and hardy plants – carried out over more than a decade. This revealed that vegetation in East Antarctica is changing rapidly in response to a drying climate. The findings are published in the journal Nature Climate Change. “Visiting Antarctica, you expect to see icy, white landscapes,” said lead scientist Prof Sharon Robinson from the University of Wollongong, in Australia. “But in some areas there are lush, green moss beds that emerge from under the snow for a growing period of maybe six weeks.” While West Antarctica and the Antarctic Peninsula are some of the fastest warming places of the planet, East Antarctica has not yet experienced much climate warming, so the scientists did not expect to see much change in the vegetation there. “But we were really surprised when we saw how fast it was changing,” Prof Robinson said. The researchers say this is the first study to show that the plants in East Antarctica are being affected by climate change and ozone depletion. “The mosses are our sentinel for the whole...
How fast can Antarctica rise when the ice melts?

How fast can Antarctica rise when the ice melts?

SOURCE: Science Nordic DATE: September 8, 2018 SNIP: At the peak of the last ice age, ice covered a much larger area of the Amundsen Sea Embayment than it does today, but it shrank to reach its modern configuration around 10,000 years ago, as shown in the figure below. Since then, the glaciers in this region have been pretty much stable until about 200 years ago, when they started to melt and retreat. This happened slowly at first, but there has been a clear increase of ice loss since 2005. Our study shows that the Earth surface, progressively relieved from the big burden of ice, is finally rising and it is doing so at an accelerating pace – up to 41 millimetres a year in 2014, which is between four and five times faster than expected. Why does the land rise when the ice melts? To explain this, we need to understand the process by which the earth rises, known as glacial isostatic adjustment to give it its proper name. A useful analogy is to imagine the structure of the Earth beneath Antarctica as a double-layer mattress with a springy, elastic layer at the top and a thick, memory foam underneath. As the ice thins, the land immediately underneath the ice sheet quickly springs back in response to the loss of weight. This is like the springy layer at the top of your mattress, which springs back as you get out of bed. This immediate response is called elastic rebound. Secondly, there is a delayed uplift as the mantle beneath the bedrock responds. This is analogous to the deeper...
Antarctica’s Ice Loss Is Speeding Up, with Sharp Acceleration in Past 5 Years

Antarctica’s Ice Loss Is Speeding Up, with Sharp Acceleration in Past 5 Years

SOURCE: Inside Climate News and Nature DATE: June 13, 2018 SNIP: The most complete assessment to date of Antarctica’s ice sheets confirms that the meltdown accelerated sharply in the past five years, and there is no sign of a slowdown. That means sea level is expected to rise at a rate that will catch some coastal communities unprepared despite persistent warnings, according to the international team of scientists publishing a series of related studies this week in the journal Nature. The scientists found that the rate of ice loss over the past five years had tripled compared to the previous two decades, suggesting an additional 6 inches of sea level rise from Antarctica alone by 2100, on top of the 2 feet already projected from all sources, including Greenland. Between 1992, when detailed satellite measurements started, and 2012, Antarctica lost about 76 billion tons of ice per year. But since 2012, that rate has tripled to about 219 billion tons of ice loss per year, the scientists found. Another study, published June 13 in the journal Science Advances, raises even more concerns about the vulnerability of Antarctic ice to global warming. Data from radar and laser readings of the ice enabled scientists with the University of Texas at Austin and the University of Waterloo to map a vast network of channels in the base of many ice sheets formed by intrusions of warm water. Some are several kilometers wide, said University of Texas at Austin researcher Jamin Greenbaum. They found the channels everywhere they looked, including beneath the ice shelf of the Totten Glacier, in East Antarctica, as well...
Unprecedented U.S.-British project launches to study the world’s most dangerous glacier

Unprecedented U.S.-British project launches to study the world’s most dangerous glacier

SOURCE: The Washington Post DATE: April 30, 2018 SNIP: The largest U.S.-British Antarctic mission in seven decades officially launched at an event in Cambridge on Monday, as the two countries pooled dollars and scientific resources for missions to West Antarctica’s Thwaites glacier — a Florida-size ice body that, scientists fear, could flood the world’s coastlines in our lifetimes. “For global sea-level change in the next century, this Thwaites glacier is almost the entire story,” said David Holland, a geoscientist at New York University. Thwaites is wide and deep and flows out of the heart of West Antarctica, a marine ice sheet that could contribute about 10 feet of global sea-level rise. Thwaites is losing ice rapidly, with its 50 billion tons per year currently driving 4 percent of global sea-level rise, and sits perched in 2,600-foot-deep waters atop a seafloor “bump” that scientists fear is the last thing holding it in place. Thwaites is a key part of the reason that recent computer modeling studies have predicted that the Antarctic could double the previously projected rate of sea-level rise during this century. It’s among the most difficult places on Earth for humans to...