Melting Greenland ice may expose entombed hazardous waste
Thursday, August 4, 2016, 4:14 - The melting of Arctic sea ice is unlike anything we've see, going back over 160 years, a new map shows the thawing underside of Greenland's ice sheet, and the melting in Greenland's extreme northwest is setting up to release cold war-era hazardous waste. It's What's Up In Climate Change.
Unprecedented decline in Arctic sea ice
Gathering together historical records from a number of sources, scientists have now given us a detailed look at the state of Arctic sea ice, back to the year 1850, to match the extensive timeline of global temperature measurements we can draw upon when assessing our changing climate.
What the end result shows is that the current loss of sea ice from the Arctic is unprecedented in the entire 166 year record!
Winter maximums (mid-March) and summer minimums (mid-September) for Arctic sea ice extent, 1850-2013, drawing from whaling ship reports and historical ice charts from Alaska, the Russian Arctic, Canada and Denmark. Credit: NOAA at NSIDC
According to the National Snow and Ice Data Center (NSIDC):
The study concludes that the current downward trend in sea ice has no precedent in duration or scale of ice loss since 1850. With the exception of the Bering Sea, none of the areas have seen sea ice extents as low as in the past decade. Historical periods that show a decrease in summertime sea ice extent in the Arctic, such as the late 1930’s and 1940’s, are smaller in magnitude than the current downward-trending period.
Adding in the 2014 and 2015 mid-September amounts only supports this conclusion, as 2014 was roughly even with 2013, and the 2015 extent was a half-million square kilometres lower than both previous years.
Now, in 2016, although the summer melt slowed throughout the first half of July (after a record-low month of June), the month came in with the third lowest extent on record. If the trend over the latter half of July and the first week in August persists, this year's melt could - at the very least - result in the second lowest ice extent on record. If the Arctic experiences exceptional warm and stormy weather through August and September, it could even rival or beat 2012 for the lowest extent on record.
Much of Greenland's ice is on slippery ground
Scientists have been carefully watching the decline of Greenland's ice sheet, as the trillions of tons of ice there are expected to have a significant impact on global sea levels in the coming years and decades due to climate change.
Looking at the tops of the ice sheets or at the edges of the glaciers isn't enough though. Scientists have now gathered data from four different sources - computer models, ice-penetrating radar, surface motion of the ice and satellite terrain data - to plot a map of the underside of the island's ice sheet.
The first map of the underside of the Greenland ice sheet. Credit: NASA Earth Observatory/Jesse Allen
Areas shaded blue on the map are those where the ice is firmly in contact with the bedrock below, thus frozen in place. The red-shaded regions are those where the bottom of the ice sheet has melted, due to being in contact with bedrock that goes through enough geothermal heating to stay above the freezing mark. The grey shaded regions between are areas of uncertainty.
Why is this important? Study lead Joe MacGregor, a glaciologist at NASA’s Goddard Space Flight Center, explains:
"We're ultimately interested in understanding how the ice sheet flows and how it will behave in the future," he said in a NASA statement. "If the ice at its bottom is at the melting point temperature, or thawed, then there could be enough liquid water there for the ice to flow faster and affect how quickly it responds to climate change."
As this is the very first map of its kind, the researchers are expecting the work to be knocked around by the scientific community, calling it "the piñata," on the road to producing an even better, and higher-resolution map in the future.
Melting Greenland ice may uncover toxins from the Cold War
So, not only is melting ice on Greenland affecting sea level rise and exacerbate climate change, but it may also release hazardous waste that has been entombed in the ice for half a century.
Back in the mid-1960s, in the midst of the Cold War, the United States Army shut down a base located in northwestern Greenland, known as Camp Century - home to Project Iceworm, a plan to house mobile nuclear missiles, transported via a railway in tunnels under the ice of northern Greenland.
When they abandoned the base, the army left behind an array of potentially harmful biological, chemical and radioactive substances that were expected to remain encased in the ice forever.
Now, however, with climate change causing unprecedented losses from the Greenland ice sheet - amounting to some 1 trillion tons of ice lost between the years 2007-2011 and another trillion tons lost between 2011-2014 - "forever" is not likely to be for as long as the US Army had hoped.
Ice elevation and glacier movement speed in northwestern Greenland (left) and images of Camp Century from construction and closer to abandonment. Credit: Colgan, et al./US gov't
According to a study led by William Colgan, a climate and glacier scientist at York University in Toronto, although northwestern Greenland is currently experiencing more snowfall than melt, resulting in a continued accumulation of snow-cover and ice there, if we continue with a "business-as-usual" approach to the climate and fossil fuels, this trend will slow and then reverse. When that happens, the melting ice will slowly uncover these hazardous substances, which could run off into the oceans, where they would negatively impact the environment.
Tallying up the full inventory of waste left behind at Camp Century, the study authors found over 9,000 tons of physical waste (buildings and the railway), 52,834 gallons [200,000 litres] of diesel fuel, 6.3 million gallons [24 million litres] of grey water, including sewage, and what the authors described as "nontrivial" amounts of polychlorinated biphenyls (PCBs) and radioactive coolant from the base's portable nuclear reactor.
By the projections in the study, the current trend in snowfall and ice loss in northwestern Greenland could reverse by the end of this century, which would lead to the eventual release of these hazardous substances into the environment.
"The question is whether it's going to come out in hundreds of years, in thousands of years, or in tens of thousands of years," said James White, a climate scientist at the University of Colorado in Boulder, according to a news release on the American Geophysical Union website. White was not involved in the study. "This stuff was going to come out anyway, but what climate change did was press the gas pedal to the floor and say, 'it's going to come out a lot faster than you thought.'"
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Watch Below: NASA plots the decline in Arctic sea ice from 1979-2015