antartica is in trouble

Antarctica—A Continent in Trouble
WHEN astronauts view the earth from space, says the book Antarctica: The Last Continent, the most distinctive feature of our planet is the ice sheet of Antarctica. It "radiates light like a great white lantern across the bottom of the world," the astronauts reported.
Containing some seven million cubic miles [30,000,000 cu km] of ice, Antarctica is an ice-manufacturing machine of continental proportions. Snow falls on the continent and packs down to form ice. Gravity forces the ice to flow slowly toward the coast, and there it slips into the sea to form massive ice shelves.—See the box on page 18.
Receding Ice Shelves
In recent years, however, accelerated melting has reduced the size of a number of ice shelves, and some have disappeared altogether. In 1995 a 500-square-mile [1,000 sq km] section of the 620-mile-long [1,000 km] Larsen Ice Shelf collapsed and broke up into thousands of icebergs, according to one report.
The area that has been affected so far by receding ice is the Antarctic Peninsula. A continuation of the Andes mountain range of South America, this S-shaped peninsula has seen a 4.5-degree-Fahrenheit [2.5 Celsius] rise in temperature over the past 50 years. As a result, James Ross Island, once enclosed by ice, can now be circumnavigated. Receding ice has also brought about a sharp increase in vegetation.
Because significant melting has occurred only in the region of the Antarctic Peninsula, some scientists are not convinced that it is an indication of global warming. However, according to a Norwegian study, Arctic ice is also in retreat. (Because the North Pole is not situated on a landmass, much Arctic ice is sea ice.) All these changes, according to the study, fit the pattern predicted to occur with global warming.
But Antarctica does more than respond to temperature changes. The continent has been described as "the vital engine which drives much of our global climate." If that is so, then future weather patterns may be affected if the continent continues to undergo changes.
In the meantime, high above Antarctica a hole twice the size of Europe has formed in the atmosphere’s ozone layer. Ozone, a form of oxygen, shields the earth from harmful ultraviolet radiation that damages eyes and causes skin cancers. Because of the increase in radiation, researchers in Antarctica must protect their skin from the sun and don goggles or sunglasses with special reflective coatings to protect their eyes. Only time will tell to what extent Antarctica’s seasonal wildlife is affected.
Delicate Continent—Tread Lightly
The above heading might be a fitting welcome for visitors to Antarctica. Why so? For several reasons, according to the Australian Antarctic Division. First, because of Antarctica’s simple ecological relationships, the environment is highly sensitive to disturbances. Second, plants grow so slowly that a footprint in a moss bed may still be visible ten years later. Damaged or weakened plants are at the mercy of Antarctica’s high winds, which can destroy whole plant communities. Third, extreme cold means that waste products can take decades to decompose. Fourth, people may inadvertently bring in microscopic life-forms alien to this isolated, and hence vulnerable, continent. Finally, the places tourists and scientists tend to frequent are the coastal fringes—the areas that are also most favorable for wildlife and vegetation. Because these areas comprise only about 2 percent of the landmass, it is easy to see why Antarctica could soon become overcrowded. That raises the question, Who polices this huge continent?
Who Rules Antarctica?
Although seven countries claim portions of Antarctica, the continent as a whole has the unique distinction of having neither a sovereign nor a citizenry. "Antarctica is the only continent on earth to be completely governed by an international agreement," reports the Australian Antarctic Division.
Called the Antarctic Treaty, the agreement was signed by 12 governments and entered into force on June 23, 1961. Since then, the number of participating nations has grown to over 40. The treaty’s objective is "to ensure, in the interest of all mankind, that Antarctica shall continue forever to be used exclusively for peaceful purposes and shall not become the scene or object of international discord."
In January 1998 the Environmental Protection Protocol to the Antarctic Treaty came into force. This protocol bans all mining and mineral exploitation in Antarctica for a minimum of 50 years. It also designates the continent and its dependent marine ecosystems as a "natural reserve devoted to peace and science." Military activities, weapons testing, and the disposal of nuclear wastes are prohibited. Even sled dogs are banned.
The Antarctic Treaty has been hailed as "an unprecedented example of international cooperation." However, there are still many problems to be resolved, including sovereignty. Who, for instance, will enforce the treaty, and how? And how will the member nations deal with the rapid growth of tourism—a potential threat to Antarctica’s delicate ecology? In recent years over 7,000 ship-borne tourists have visited Antarctica annually, and this figure is expected to double before long.
Other challenges may arise in the future. For instance, what if scientists find valuable mineral or oil deposits? Will the treaty prevent commercial exploitation and the pollution that often follows? Treaties can be changed, and the Antarctic Treaty is no exception. In fact, Article 12 makes provision for the treaty to be "modified or amended at any time by unanimous agreement of the Contracting Parties."
Of course, no treaty is capable of shielding Antarctica from the effluents of the modern, industrialized world. What a pity if the beautiful "white lantern" at the bottom of the globe were to be sullied by the far-reaching effects of human greed and ignorance! To hurt Antarctica is to injure humankind. If Antarctica teaches us anything, it is that the whole earth—like the human body—is an interrelated system, perfectly coordinated by the Creator both to sustain life and to give us enjoyment.
WHAT IS AN ICE SHELF?
High in Antarctica’s interior, streams of ice formed by falling snow work their way down toward the coast—some flowing as much as half a mile a year, according to recent satellite radar images. Many of these ice streams merge like tributaries, forming huge rivers of ice. When they reach the sea, these frozen rivers float on the water to form ice shelves, the largest being the Ross Ice Shelf (shown here). Fed by no less than seven ice streams or glaciers, it is the size of France and up to half a mile thick in places.
Under normal circumstances, ice shelves do not retreat. As the glaciers feed more ice into the shelf, the outer extremity of the shelf is pushed farther out to sea, like toothpaste being squeezed from a tube. There huge chunks eventually break off (a process called calving), and these chunks become icebergs. Some icebergs are "as huge as 5,000 square miles [13,000 sq km]," says The World Book Encyclopedia. In recent years, though, calving has accelerated and ice shelves have retreated, some even disappearing altogether. Even so, this does not raise sea levels. Why not? Because ice shelves are already afloat, displacing their weight in water. But if the ice on the Antarctic mainland were to melt, it would be like emptying a seven-million-cubic-mile [30,000,000 cu km] reservoir into the sea! Sea levels would rise some 200 feet [65 m]!

Ice shelves are not to be confused with pack ice. Pack ice begins as ice floes that form on the sea during winter when the water surface freezes. These floes then merge to form pack ice. The reverse occurs during summer. Icebergs do not form from pack ice but, rather, from ice shelves.

Massive blocks of ice calve off the Ross Ice Shelf. The ice shelf here rises about 200 feet above