Water Is Streaming Across Antarctica

SOURCE: Columbia University Earth Institute DATE: April 19, 2017 SNIP: In the first such continent-wide survey, scientists have found extensive drainages of meltwater flowing over parts of Antarctica’s ice during the brief summer. Researchers already knew such features existed, but assumed they were confined mainly to Antarctica’s fastest-warming, most northerly reaches. Many of the newly mapped drainages are not new, but the fact they exist at all is significant; they appear to proliferate with small upswings in temperature, so warming projected for this century could quickly magnify their influence on sea level. An accompanying study looks at how such systems might influence the great ice shelves ringing the continent, which some researchers fear could collapse, bringing catastrophic sea-level rises. “This is not in the future—this is widespread now, and has been for decades,” said lead author Jonathan Kingslake, a glaciologist at Columbia University’s Lamont-Doherty Earth Observatory. “I think most polar scientists have considered water moving across the surface of Antarctica to be extremely rare. But we found a lot of it, over very large areas.” Many of the newly mapped drainages start near mountains poking through glaciers, or in areas where powerful winds have scoured snow off underlying bluish ice. These features are darker than the mostly snow-covered ice sheet, and so absorb more solar energy. This causes melting, and on a slope, liquid water then melts a path downhill through overlying snow. If the continent warms this century as projected, this process will occur on a much larger scale, say the authors. “This study tells us there’s already a lot more melting going on than we thought,” said...
Arctic permafrost is thawing faster than expected

Arctic permafrost is thawing faster than expected

SOURCE: CBC DATE: April 9, 2016 SNIP: Scientists estimate that the amount of carbon dioxide locked up in the Arctic permafrost is twice the amount found in the atmosphere of the entire planet. Because much of the permafrost was thought to be protected from climate change, scientists believed that CO2 would not be released. But a new study by Dr. Anna Liljedahl, a Research Assistant Professor from the Water and Environment Research Center at the University of Alaska, has found that in some areas of the Arctic, the permafrost is thawing faster than expected. Winter cracks open the ground, then fill in with summer meltwater, forming ice wedges 10 to 15 metres deep in the permafrost. Rising temperatures in recent years have resulted in a degradation of the ice wedges, which results in a thawing of the...
Antarctic ice melting faster than expected

Antarctic ice melting faster than expected

SOURCE: Smithsonian TweenTribune DATE: April 11, 2016 AUTHOR: Seth Borenstein, Associated Press SNIP: Warmer air, less frigid water and gravity may combine to make parts of Antarctica’s western ice sheet melt far faster than scientists had thought. Sea levels could rise much more than expected. It all could happen by the end of the century. The results of new physics-based computer simulations have been released. They forecast dramatic increases in melting. It could occur in the vulnerable western edge of Antarctica. The huge land mass at the southern end of the Earth is a continent. In a worst-case scenario, that could raise sea level in 2100 by 18 to 34 inches. That is much more than an international panel of climate scientists predicted. They made that prediction just three years...
Earth’s Ice Is Melting Much Faster Than Forecast. Here’s Why That’s Worrying.

Earth’s Ice Is Melting Much Faster Than Forecast. Here’s Why That’s Worrying.

SOURCE: The Huffington Post DATE: August 4, 2015 AUTHOR: Jason E. Box, Professor in Glaciology, Geological Survey of Denmark and Greenland SNIP: Despite decades of progress by many clever scientists engaged with climate modeling, climate models used to inform policymakers don’t yet encode key pieces of physics that have ice melting so fast. They don’t incorporate thermal collapse — ice softening due to increasing meltwater infiltration. Climate models also don’t yet incorporate increasing forced ocean convection at the ocean fronts of glaciers that forces a heat exchange between warming water and ice at the grounding lines. Climate models don’t yet include ice algae growth that darkens the bare ice surface. Climate models don’t yet prescribe background dark bare ice from outcropping dust on Greenland from the dusty last ice age. Climate models don’t include increasing wildfire delivering more light-trapping dark particles to bright snow covered areas, yielding earlier melt onset and more intense summer melting. As a result of some of these factors and probably some as yet unknown others, climate models have under-predicted the loss rate of snow on land by a factor of four and the loss of sea ice by a factor of two. … So, alas, when it comes to ice, how fast it can go and how fast the sea will rise, if I were a betting man, I’d put my money on it going faster than...