‘Extraordinary thinning’ of ice sheets revealed deep inside Antarctica

‘Extraordinary thinning’ of ice sheets revealed deep inside Antarctica

SOURCE: The Guardian DATE: May 16, 2019 SNIP: Ice losses are rapidly spreading deep into the interior of the Antarctic, new analysis of satellite data shows. The warming of the Southern Ocean is resulting in glaciers sliding into the sea increasingly rapidly, with ice now being lost five times faster than in the 1990s. The West Antarctic ice sheet was stable in 1992 but up to a quarter of its expanse is now thinning. More than 100 metres of ice thickness has been lost in the worst-hit places. A complete loss of the West Antarctic ice sheet would drive global sea levels up by about five metres, drowning coastal cities around the world. The current losses are doubling every decade, the scientists said, and sea level rise are now running at the extreme end of projections made just a few years ago. “From a standing start in the 1990s, thinning has spread inland progressively over the past 25 years – that is rapid in glaciological terms,” said Prof Andy Shepherd, of Leeds University in the UK, who led the study. “The speed of drawing down ice from an ice sheet used to be spoken of in geological timescales, but that has now been replaced by people’s...
‘When the Glaciers Disappear, Those Species Will Go Extinct’

‘When the Glaciers Disappear, Those Species Will Go Extinct’

SOURCE: New York Times DATE: April 17, 2019 SNIP: When it was built in the early 1900s, the road into Mount Rainier National Park from the west passed near the foot of the Nisqually Glacier, one of the mountain’s longest. Visitors could stop for ice cream at a stand built among the glacial boulders and gaze in awe at the ice. The ice cream stand is long gone. The glacier now ends more than a mile farther up the mountain. As surely as they are melting elsewhere around the world, glaciers are disappearing in North America, too. This great melting will affect ecosystems and the creatures within them, like the salmon that spawn in meltwater streams. This is on top of the effects on the water that billions of people drink, the crops they grow and the energy they need. Glacier-fed ecosystems are delicately balanced, populated by species that have adapted to the unique conditions of the streams. As glaciers shrink and meltwater eventually declines, changes in water temperature, nutrient content and other characteristics will disrupt those natural communities. “Lots of these ecosystems have evolved with the glaciers for thousands of years or maybe longer,” said Jon Riedel, a geologist with the National Park Service who has established glacier monitoring programs at Rainier and other parks. Streams that are mostly fed by glacial meltwater often have unique species that have adapted to the cold conditions. Reducing or eventually eliminating the contribution of this meltwater will raise stream temperatures. Even a small temperature increase can have potentially negative effects. “Certain species like cold water,” said Alexander M. Milner, a professor...
Siren sounds on nuclear fallout embedded in melting glaciers

Siren sounds on nuclear fallout embedded in melting glaciers

SOURCE: Phys.org DATE: April 10, 2019 SNIP: Radioactive fallout from nuclear meltdowns and weapons testing is nestled in glaciers across the world, scientists said Wednesday, warning of a potentially hazardous time bomb as rising temperatures melt the icy residue. For the first time, an international team of scientists has studied the presence of nuclear fallout in ice surface sediments on glaciers across the Arctic, Iceland the Alps, Caucasus mountains, British Columbia and Antarctica. It found manmade radioactive material at all 17 survey sites, often at concentrations at least 10 times higher than levels elsewhere. When radioactive material is released into the atmosphere, it falls to earth as acid rain, some of which is absorbed by plants and soil. But when it falls as snow and settles in the ice, it forms heavier sediment which collects in glaciers, concentrating the levels of nuclear residue. As well as disasters, radioactive material produced from weapons testing was also detected at several research sites. One of the most potentially hazardous residues of human nuclear activity is Americium, which is produced when Plutonium decays. Whereas Plutonium has a half-life of 14 years, Americium lasts 400. “Americium is more soluble in the environment and it is a stronger alpha (radiation) emitter. Both of those things are bad in terms of uptake into the food chain,” said...
Melting glaciers contribute a third of sea-level rise

Melting glaciers contribute a third of sea-level rise

SOURCE: National Geographic and Phys.org DATE: April 8, 2019 SNIP: Like an ice cube on a hot summer day, many of Earth’s glaciers are shrinking. Last January, a study in Nature Climate Change showed the world’s glaciers are the smallest they’ve been in human history, revealing radiocarbon material that hasn’t been exposed for 40,000 years. Now, new research published in Nature quantifies how much the world’s lost glaciers have contributed to rising sea levels. Glaciers have lost more than 9 trillion tons (that is 9,625,000,000,000 tons) of ice between 1961 and 2016, which has resulted in global sea levels rising by 27 millimeters in this period. The largest contributors were glaciers in Alaska, followed by the melting ice fields in Patagonia and glaciers in the Arctic regions. Glaciers in the European Alps, the Caucasus and New Zealand were also subject to significant ice loss; however, due to their relatively small glacierized areas, they played only a minor role when it comes to the rising global sea levels. They found mountain glaciers contribute roughly a third of measured sea-level rise—the same contribution to sea-level rise as the Greenland ice sheet and more than the contribution of the Antarctic ice sheet. Their research also highlighted that many of the world’s glaciers may disappear in the next century. The global mass loss of glacier ice has increased significantly in the last 30 years, and currently amounts to 335 billion tons of lost ice each year. This corresponds to an increase in sea levels of almost one millimeter per...
Glacier in Russian Arctic Goes From Moving 60 Feet a Year to 60 Feet a Day

Glacier in Russian Arctic Goes From Moving 60 Feet a Year to 60 Feet a Day

SOURCE: Weather.com and NASA DATE: April 8, 2019 SNIP: Satellite images of dramatic changes in a glacier in the Russian High Arctic is forcing scientists to rethink how cold-based glaciers work. Cold-based glaciers exist at high latitudes that receive little snow or rain. They rarely move more than a few yards per year. University of Colorado Boulder glaciologist Michael Willis was studying the Vavilov Ice Cap on October Revolution Island in the Kara Sea north of Siberia when he discovered the glacier began sliding dozens of times faster than is typical, according to a blog post from NASA. “The fact that an apparently stable, cold-based glacier suddenly went from moving 20 meters per year to 20 meters per day was extremely unusual, perhaps unprecedented,” Willis said. “The numbers here are simply nuts. Before this happened, as far as I knew, cold-based glaciers simply didn’t do that … couldn’t do that.” “This event has forced us to rethink how cold-based glaciers work,” Willis said. “It may be that they can respond more quickly to warming climate or changes at their bases than we have...