Arctic ice melting at alarming rate

Fish and other marine life accustomed to swimming the salty Arctic Ocean will soon have to adapt to fresher water or find a new home.

The Arctic Ocean, the smallest of the world’s four oceans, is becoming less salty every day as a result of melting ice, say scientists.   And that’s just one of the problems posed by a sudden massive increase in the disappearance of Arctic ice.

Two separate studies by NASA, using different satellite monitoring technologies, both show a dramatic surge in the disappearance of Arctic ice cover in the last two years.

The first, from the Jet Propulsion Laboratory in California, shows that Arctic perennial sea ice, which normally survives the summer melt season and remains year-round, shrank by 14 per cent in just 12 months between 2004 and 2005.

Overall, the ice cover decreased by 720,000 sq km—an area almost the size of Turkey—in a single year.

The second study, from the Goddard Space Flight Centre, in Maryland, shows that the perennial ice-melting rate, which has averaged 0.15 percent a year since satellite observations began in 1979, has suddenly accelerated.

In the past two winters, the rate has increased to 6 percent a year—more than 30 times faster than previously

Part of the acceleration can be attributed to a decrease in the amount of light reflected away from the earth.  The white surface of sea ice reflects radiation from the sun.  When ice turns to dark ocean water, it absorbs more heat from the sun.  This warmer water in turn melts more sea ice, perpetuating the cycle.

The floating cap of sea ice on the Arctic Ocean shrank this summer to what is probably its smallest size in at least a century of record keeping, continuing a trend toward less summer ice, a team of climate experts has reported.

In addition to the melting of ice both on sea and land, scientists have warned that permafrost—the permanently frozen layer of soil that underlies much of the Arctic—will also melt and eventually disappear in some areas.  Such thawing could release additional greenhouse gases stored in the permafrost for thousands of years, triggering further global warming.

“Since sea ice and sheet ice both consist of fresh water, the result will be a huge increase in the amount of fresh water in the Arctic Ocean,” said Professor Abdulmalik al-Jibly, a climate scientist with the Geography Department in the Faculty of Arts, Sana’a University.

The salinity rate also decreases as rainfall and the number of rivers flowing into the Arctic Ocean increases.  The scientists calculated that increased rainfall and river outflow between 1965 and 1995 dumped an extra 20,000 cubic kilometers of freshwater into the ocean.  Melting sea ice contributed a further 15,000 square km and glaciers 2000 square km.  This is consistent with the decrease in the salinity of the Arctic Ocean over the same period.

This fresher water endangers the lives of the marine life that abounds in the open seas: fish, hares, polar bears, walruses, whales, seals, gulls, and guillemots.

The decrease in ice could also lead to the extinction—in our children’s lifetime—of animals such as the polar bear, which needs the ice to hunt seals.

The changes are alarming scientists and environmentalists, because they far exceed the rate at which computer models of climate change predict the Arctic ice will melt as a result of global warming —which is already fairly rapid.

If climate change is not curbed, the Arctic ice will have completely disappeared by 2070, and people will be able to sail to the North Pole.  But if ice continues to melt at the current rate, the Arctic icecap will melted decades before that.

The Arctic Ocean lies almost entirely above the Arctic Circle.  Almost completely surrounded by land, it abuts Eurasia, North America, Greenland, and several islands.  The Arctic Ocean has an area of 14,090,000 square kilometers and an average depth of 3,658 meters off of the continental shelf.  The lowest point is the Fram Basin, which is 4,665 meters deep.  The Artic Ocean has the widest continental shelf of all the oceans, and its coastline is 45,389 kilometers in length.

Scientists are also concerned that elevated temperatures in the Arctic may cause large amounts of fresh meltwater to enter the North Atlantic, possibly disrupting global ocean current patterns.  Potentially severe changes in the Earth’s climate may then ensue.

The planet’s steadily warming atmosphere also contributes to the melting of sea ice, as well as the melting of the ice sheets covering Greenland.

“The emissions of cars, factories, etc., are full of carbon dioxide, which is the main cause of the global warming,” said al-Jibly.  “Both the smoke released from MacDonald’s Restaurants and freon gas, which is used in refrigerators, are full of chlorofluorocarbons.” Chloroflourocarbons, poularly known as CFCs, contribute to the hole in the ozone layer over the North Pole and increase the warmth of the earth.

“Melting of Arctic glaciers and ice sheets will raise sea levels worldwide, flooding the coastal areas where many of the world’s people live,” said Professor Naji al-Lahabi, a member of the Geography Department at Sana’a University.  “Melting sea ice has already dramatically affected the indigenous people and animals in the Arctic.”

Scientists were unable to identify any natural processes that might slow the de-icing of the Arctic, and did not observe any natural mechanism that could stop the dramatic loss of ice.  “I think humans could step on the brakes by reducing carbon dioxide emissions,” said al-Lahabi.  “Therefore, it is really important that we try as hard as we can, and as soon as we can, to dramatically reduce such emissions.”

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