Answers to questions about the Arctic's shrinking ice cap and its global significance.
1. Why are global warming specialists watching the Arctic so closely?
The Arctic is global warming's canary in the coal mine. It's a highly sensitive region, and it's being profoundly affected by the changing climate. Most scientists view what's happening now in the Arctic as a harbinger of things to come.
Since 1979, the size of the summer polar ice cap has shrunk more than 20 percent. (Illustration from NASA)
2. What kinds of changes are taking place in the Arctic now?
Average temperatures in the Arctic region are rising twice as fast as they are elsewhere in the world. Arctic ice is getting thinner, melting and rupturing. For example, the largest single block of ice in the Arctic, the Ward Hunt Ice Shelf, had been around for 3,000 years before it started cracking in 2000. Within two years it had split all the way through and is now breaking into pieces.
The polar ice cap as a whole is shrinking. Images from NASA satellites show that the area of permanent ice cover is contracting at a rate of 9 percent each decade. If this trend continues, summers in the Arctic could become ice-free by the end of the century.
3. How does this dramatic ice melt affect the Arctic?
The melting of once-permanent ice is already affecting native people, wildlife and plants. When the Ward Hunt Ice Shelf splintered, the rare freshwater lake it enclosed, along with its unique ecosystem, drained into the ocean. Polar bears, whales, walrus and seals are changing their feeding and migration patterns, making it harder for native people to hunt them. And along Arctic coastlines, entire villages will be uprooted because they're in danger of being swamped. The native people of the Arctic view global warming as a threat to their cultural identity and their very survival.
4. Will Arctic ice melt have any effects beyond the polar region?
Yes -- the contraction of the Arctic ice cap is accelerating global warming. Snow and ice usually form a protective, cooling layer over the Arctic. When that covering melts, the earth absorbs more sunlight and gets hotter. And the latest scientific data confirm the far-reaching effects of climbing global temperatures.
Rising temperatures are already affecting Alaska, where the spruce bark beetle is breeding faster in the warmer weather. These pests now sneak in an extra generation each year. From 1993 to 2003, they chewed up 3.4 million acres of Alaskan forest.
Melting glaciers and land-based ice sheets also contribute to rising sea levels, threatening low-lying areas around the globe with beach erosion, coastal flooding, and contamination of freshwater supplies. (Sea level is not affected when floating sea ice melts.) At particular risk are island nations like the Maldives; over half of that nation's populated islands lie less than 6 feet above sea level. Even major cities like Shanghai and Lagos would face similar problems, as they also lie just six feet above present water levels.
Rising seas would severely impact the United States as well. Scientists project as much as a 3-foot sea-level rise by 2100. According to a 2001 U.S. Environmental Protection Agency study, this increase would inundate some 22,400 square miles of land along the Atlantic and Gulf coasts of the United States, primarily in Louisiana, Texas, Florida and North Carolina.
A warmer Arctic will also affect weather patterns and thus food production around the world. Wheat farming in Kansas, for example, would be profoundly affected by the loss of ice cover in the Arctic. According to a NASA Goddard Institute of Space Studies computer model, Kansas would be 4 degrees warmer in the winter without Arctic ice, which normally creates cold air masses that frequently slide southward into the United States. Warmer winters are bad news for wheat farmers, who need freezing temperatures to grow winter wheat. And in summer, warmer days would rob Kansas soil of 10 percent of its moisture, drying out valuable cropland.
5. Can we do anything to stop global warming?
Yes. When we burn fossil fuels -- oil, coal and gas -- to generate electricity and power our vehicles, we produce the heat-trapping gases that cause global warming. The more we burn, the faster churns the engine of global climate change. Thus the most important thing we can do is save energy.
And we can do it. Technologies exist today to make cars that run cleaner and burn less gas, generate electricity from wind and sun, modernize power plants, and build refrigerators, air conditioners and whole buildings that use less power. As individuals, each of us can take steps to save energy and fight global warming.
(Source: Natural Resources Defense Council)