Antarctic Sea Ice May Force Research Stations to Move
Growing sea ice surrounding could prompt scientists to relocate research stations on the continent.
Growing sea ice surrounding Antarctica could prompt scientists to consider relocating research stations on the continent, according to the operations manager of the Australian Antarctic Division.
Rob Wooding said that resupplying Australia's Mawson Station -- the longest continuously operated outpost in Antarctica -- relied on access to a bay, a task increasingly complicated by sea ice blocking the way.
"We are noticing that the sea ice situation is becoming more difficult," Wooding told a media briefing on Monday ahead of two days of meetings between top Antarctic science and logistics experts in Hobart, the capital of Tasmania.
Wooding said that at Mawson, the ice typically only breaks up for one or two months of the summer, but in the last four to six years this has not happened every year, and some years only partially.
"In the 2013-4 season we couldn't get anywhere near Mawson due to the sea ice and we had to get fuel in there by helicopter which is inadequate for the long-term sustainability of the station," he said, adding that the French and Japanese had similar problems.
Wooding said Australia had not yet come close to shutting down a base because of sea ice, but had to look at "unusual measures" to keep operating.
Tony Worby, from an Australian centre studying Antarctic climate and ecosystems, said that in contrast to the Arctic where global warming is causing ice to melt and glaciers to shrink, sea ice around Antarcticawas increasing.
It hit a new record in September last year, with the US-based National Snow and Ice Data Center reporting that the ice averaged 20.0 million square kilometres (7.72 million square miles) during the month.
Scientists have struggled to predict sea ice conditions, which are believed to be affected by the strong winds of the Southern Ocean which can push the ice out from the continent of Antarctica.
This does not happen in the Arctic because the ocean is hemmed in by land masses.
"We know that the changing Antarctic sea ice extent is very largely driven by changes in wind," Worby said.
Local conditions can also have a dramatic effect, with icebergs sometimes unpredictably grounding themselves in inconvenient locations and staying there for years as more sea ice builds around them.
Wooding said potential solutions included using large aircraft to deliver crucial fuel and other supplies to the outposts, as well as hovercraft, or funding other ways to resupply stations.
"I think a lot of it really will revolve around perhaps shifting more to an over-ice approach, or to even thinking about where your stations are located -- I think (that) is something that will have to be looked at over time as well," he said.
"There are some spots that may become more difficult for operations."
Worby said he did not believe the ice would become so thick that operations would become impossible.
But he told the briefing: "It's almost an inevitability that we are going to get ships stuck occasionally -- it's just the nature of working down in Antarctica."
He said because the ice was thickest around the continent, sometimes several meters, logistics teams could unload heavy equipment such as tractors off ships and drive them ashore.
Worby added that while Antarctic sea ice was increasing, the overall net trend remained modest while a significant component of the increase seen recently could be natural variability.
A C-17 sits on the ice runway at McMurdo Station, Antarctica.
Extreme Engineering in Antarctica
Jan. 15, 2012--
Engineers with British Antarctic Survey have now made it possible to go where no human has gone before: a mile down through solid ice to a buried lake that could harbor life forms never seen before and promises to reveal vital clues to past climate change.
SCIENCE CHANNEL VIDEO: Ice King
Enduring whipping winds and temperatures of minus 35 degrees Celsius (not counting the wind chill), the engineers used powerful tractor-trains to transport nearly 70 metric tons of drilling equipment across Antarctica's ice, over deep snow and steep mountain passes, to one of the most remote and hostile locations on the planet. The target of this grueling journey: a spot on the ice high above Lake Ellsworth, a mysterious and untouched pocket of liquid water deep inside the West Antarctic Ice Sheet. Now that the equipment is in place, a research team will return to in November to drill a three-kilometer borehole into Lake Ellsworth to collect water and sediment. If they succeed, Ellsworth will become the first of Antarctica's 387 known subglacial lakes to be measured and sampled directly.
NEWS: Antarctic Drilling Plan Raises Concerns
A cargo plane carried the tractors and drilling equipment for the Lake Ellsworth mission as far as Union Glacier, a site in the Ellsworth Mountains that serves as the major hub for all scientific operations to Antarctica's remote interior.
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To get the equipment from Union Glacier to the Lake Ellsworth drilling site, the engineers hitched powerful tractors to sledges and skis to haul the heavy blue containers containing the drilling equipment.
Soft, deep snow and concrete-hard sastrugi snow forms slowed progress, but the tractor-train reached the Lake Ellsworth drilling site in three days.
MARKING THE SITE
Upon arrival, an engineer fits GPS locators at the corners of the equipment storage. Windblown snow will partially bury the equipment over the coming Antarctic winter, making it otherwise difficult to find when the science team returns in November to start drilling. (Antarctic summers are too short to transport the equipment and accomplish the drilling in a single season.) In the coming months, this precious cargo will endure wind chills reaching minus almost a hundred degrees below zero and wind gusts over 100 miles per hour.
Spectacular explosions of snow, like this one detonated at the Lake Ellsworth drilling site during a previous visit, helped scientists decipher the shape of the buried lake. Researchers set off the explosions and then use seismic equipment to record the sound waves reflecting off rock, ice, water and other materials within the ice.
Seismic studies have revealed that Lake Ellsworth is a long, narrow U-shaped lake approximately 7.5 miles by about a mile wide. It is nearly 500 feet deep at its deepest point. Ellsworth and other subglacial lakes in Antarctica can remain unfrozen because the ice on top provides insulation for the heat rising up through the bedrock from the earth’s core, melting ice near the base of the ice sheet. This melted water flows into hollows and valleys beneath the ice just as it does on the land surface to form lakes. The largest and most well-known subglacial lake is Lake Vostok on East Antarctica, which Russian scientists have been trying to access, so far unsuccessfully. PHOTOS: New Antarctic Vent Community Found
Small planes can land safely at the Lake Ellsworth drilling site during the summer months. Getting people and basic supplies to the site in November will not take the extreme effort of delivering the drilling equipment. But that doesn't mean the work will be easy. The team will live in tents and work on location for about six weeks.
GETTING TO THE LAKE
Researchers will use a stream of high-pressure hot water blasted from the end of this high-tech yellow hose to drill through the frozen ice sheet lying above the Lake Ellsworth. The hose is long enough to extend from the surface down into the buried lake and strong enough to support its own weight, as well as that of the drill nozzle. Other equipment delivered by tractor-train included: (1) an industrial-sized boiler to heat 30,000 liters of hot water to nearly 100 degrees for the drill (2) three large surface tanks (each with a 16-foot diameter) to store water above freezing point in temperatures as low as minus 4 degrees Fahrenheit and (3) several large-scale generators to provide electrical power to the drill. Through a borehole carved using hot-water drill, the team will lower a titanium probe to measure and sample the water, followed by a corer to extract sediment from the lake. They will have just 60 hours to collect water and sediment samples before the borehole re-freezes. The hot water drill will use and recycle the existing ice on site for the drilling fluid, minimizing the potential for contamination of the lake. All equipment was designed and manufactured to meet space-industry standards for "clean" technology.
Soon the sun will set for the last time over the Lake Ellsworth drilling site, bringing several long weeks of darkness. The engineers and scientists will return with the light, ready to make history. The waters of Lake Ellsworth have been cut of from all light for as long as half a million years. Also under high pressure all that time, the hidden lake may have evolved unusual forms of microbial life. If such microbes turn out to exist, they could help explain how life managed to survive during global deep freezes of the Earth's distant past -- during the so-called Snowball Earth episodes, when most if not all of the planet was enshrouded in ice. And they might up the odds that life could have evolved in other extreme environments, such as the liquid water known to exist beneath the icy surface of Jupiter's moon Europa. Now we just have to wait and see.
READ MORE ARTICLES BY SARAH SIMPSON