Breaking the Ice
By Kurt Loft, Tampa Tribune, Fla.
Nov. 14–TAMPA — A pair of ships recently voyaged to the top of the world to study global climate change, the first to traverse a region of ice-covered sea between Alaska and the North Pole.
The U.S. Coast Guard’s Healy and the Swedish vessel Oden plowed through dense sheets of ice in their effort to better understand the Arctic’s role in Earth’s ocean and climate systems. While much of the research will take years to compile and publish, one thing was made immediately clear: The Arctic is slowly losing its chill.
“All indications are that the Arctic Ocean summer ice cover is retreating, with a rate of about 8 percent per decade,” says team member Jim Swift, a researcher at Scripps Institution of Oceanography near San Diego. “There are still regions with heavy ice — we were in some of them — but this summer continued the trend of this remarkable retreat.”
The trip was arduous. Although the same area — known as the Canadian Basin — had been crossed by submarines below the ice, the central Arctic Ocean is one of the planet’s least-explored regions. The heavy concentration of floating sea ice, often 10 feet thick, makes travel dangerous and often impassible.
Ships carrying early explorers have been crushed by colliding ice floes, and their crews left to starve or freeze to death. Even in the late summer and early fall, temperatures can dip to 0 degrees Fahrenheit at night, which translates to minus 26 degrees with a 30 mph wind.
At these temperatures, frostbite can occur within a half hour. Winter is out of the question, when temperatures dip to 90 degrees below zero. The crews of both ships, however, enjoyed basking in the relative warmth of 10 degrees Fahrenheit.
“We were at the end of summer,” Swift says. “The big factor in terms of comfort is wind chill. One must really bundle up, in a serious way, when the wind gets blowing, and you have to be on deck for a long time.”
Swift and his colleagues spent nearly six weeks on the trip and collected a wealth of data about sea ice, ecosystems, extreme northern climate and marine life. Scientists are concerned about the slow thaw of ice because they need to better understand how it might affect sea levels. Just as important, the melting ice could alter global ocean circulation and the amount of solar energy absorbed or reflected back into space.
The Earth’s ice caps are like enormous mirrors; if they were to shrink, more of the sun’s energy would be absorbed by the sea.
“Ice is highly reflective to incoming solar radiation, and the days are long in summer,” Swift says. “What if the ice cover began to severely retreat each summer? With the long summer days, there could be a change in the heat balance of the polar regions. This could affect the steering of and interactions with the weather patterns in temperate latitudes.”
Slowly receding Arctic ice may present another problem, Swift says: “Permafrost holds large reserves of greenhouse gases, which might get ‘burped’ into the atmosphere as the Arctic warms, potentially accelerating the greenhouse gas portion of atmospheric warming over the globe.”
The Healy and Oden often worked side by side, especially in thick ice. The conditions forced the ships to combine their power and weight on single ice floes, breaking them apart at high enough speeds to keep from stalling. If a ship runs too slow, it can become trapped and unable to ram over the floe.
The Healy breaks ice by riding its heavy bow above the ice, then lowering it and breaking the floe into chunks.
“A big factor is whether the ice is ‘compressed’ or not by the wind,” Swift says. “If the ice is not under compression, it’s easier for the icebreakers. If the ice is under compression, there’s nowhere for it to go and even a large icebreaker can get stuck for a while.”
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