Life on the edge: a high school senior spreads the word about how global warming is threatening his remote community's livelihood.

Imagine an island that's roughly the size of Delaware, with a population of fewer than 2,000 people. There, average winter temperatures range from a nose-numbing -22[degrees]C to -12[degrees]C (-7[degrees]F to 11[degrees]F), and a "hot" summer day may top out at just 10[degrees]C (50[degrees]F). For six months out of the year, the seas surrounding this island are mostly frozen. This is St. Lawrence Island, Alaska (see map, right). This is my destination.

I have been onboard the Healy icebreaker with scientists Lee Cooper and Jackie Grebmeier of the University of Tennessee. We have been sailing in the northern Bering Sea, studying how the plants and animals are responding to Earth's rising temperatures. But for one day, I will leave the ship behind and explore dry land.

REMOTE WORLD

I hop into a helicopter that is sitting on the Healy's deck and fly across the frozen Bering Sea. After traveling for 129 kilometers (80 miles), the pilot lands the helicopter on St. Lawrence Island.

Bobby Ungwiluk, a resident of the village of Gambell on the northwest tip of the island, greets me when I land. At 18 years old, Bobby is a celebrity of sorts in the village: Last year, as an 11-grader at John Apangalook Memorial High School, he nabbed first place in the Bering Strait School District's science fair and won numerous awards at Alaska's statewide science and engineering fair. His science project examined the effect of climate change on sea ice--and how the changes are affecting some native Alaskans' way of life.

Like most people who live on St. Lawrence Island, Bobby is Siberian Yupik. This cultural group of Eskimo people has occupied the region for more than 2,000 years. In keeping with longstanding traditions, people of the community today are subsistence hunters. For survival, they hunt--while following strict government hunting guidelines--for walruses, seals, bowhead whales, and other animals. "An important part of my own life is as a member of a whaling crew," says Bobby. "Hunting from a walrus-skin boat connects my people to our long heritage, defining who we are. I helped bring in a whale when I was 13, and another one when I was 15."

The Siberian Yupik of St. Lawrence Island rely on these animals--as well as the few plants and berries that manage to grow in the harsh environment--to provide them with the nutrients they need to stay healthy. Other foods like bread, milk, hamburger meat, and canned vegetables are flown onto the island from mainland Alaska, but the goods are very expensive.

THREATENED BY HEAT

Up until now, marine ice conditions have made it possible for residents of St. Lawrence Island to hunt as their ancestors did. But things are changing: Global warming is threatening their way of life.

When people around the world burn fossil fuels like coal and oil to power their homes, factories, and vehicles, they release carbon dioxide and other greenhouse gases into the atmosphere. These gases build up, insulating the planet. As a result, Earth's average temperature is rising.

Residents of Savoonga, the only other village on St. Lawrence Island, have been taking measurements of the air temperature over time. Their data show that springlike temperatures occur earlier now than they used to (see Nuts & Bolts, right). The ice surrounding the island is melting earlier too, making conditions dangerous for native hunters. The hunters could fall through thin ice, or even get trapped by the ice as it shifts with the wind and sea currents.

That has Bobby concerned. So he decided to undertake a science project to see if the melting of Arctic ice could be reversed if people were to reduce greenhouse gases. Bobby hypothesized that seas heated by global warming would be slow to cool even if greenhouse gases were reduced.

TESTING THE WATERS

To test his hypothesis, Bobby--with help from his schoolmates--created a model of the Earth-sun climate system. He used gravel to represent Earth's landmasses and bottles of water to simulate Earth's oceans. He placed these items inside a cardboard box, which represented the planet's insulating atmosphere.

Next, Bobby shone a 100-watt light bulb--the "sun"--onto the model and simultaneously recorded the temperature of the air, gravel, and water inside the box over time. Then he placed pieces of cardboard on top of the box to simulate the addition of insulating greenhouse gases. Again, he recorded the temperature of the air, gravel, and water over time. Finally, he removed the pieces of cardboard to simulate the removal of greenhouse gases from the atmosphere and recorded the changes in temperatures.

As he suspected, Bobby found that when he added cardboard pieces to simulate insulating greenhouse gases, the temperature of the atmosphere in his model rose quickly and the temperature of the modeled oceans rose more slowly. When he removed the modeled greenhouse gases, the air temperature dropped quickly, while that of the modeled oceans took longer to cool down.

"We are not sure how accurately our model simulates the real world," says Bobby. But "we have good reasons to feel that once ocean warming begins to melt sea ice, it will not be easy to reverse this melting." Bobby hopes that everyone--from policy makers to kids--will work together to stop climate change.

web extra

This year begins the International Polar Year, a time when scientists will focus on topics affecting Earth's polar regions. For related activities, visit: www.ipy.gov

nuts & bolts

Residents of the village of Savoonga on St. Lawrence Island have been keeping track of the surface air temperature there. In which year did temperatures heat up to 0[degrees]C the earliest?

[GRAPHIC OMITTED]

cool tips

Want to fight global warming? Reduce your use of fossil fuels. Here's how:

1. Buy local goods. They don't have to be shipped from far away. This saves on gasoline.

2. Use rechargeable batteries. That way, fewer batteries will be manufactured.

3. On hot days, open car windows rather than use the air conditioner.

EARTH: Climate Change Life on the Edge

PRE-READING PROMPTS

Jump-start your lesson with these pre-reading questions:

* Each year, each person in the U.S. is responsible for emitting 20 tons of carbon dioxide from the burning of oil, natural gas, and coal. In India, that amount is just 1 ton. How does the burning of these fossil fuels affect Earth's polar regions?

* Some greenhouse gases stay in the atmosphere for just a few days, but others can remain for decades, centuries, or even millennia. How might the atmosphere respond if levels of heat-trapping greenhouse gases were reduced?

CRITICAL THINKING:

* What activities that you perform daily require the burning of fossil fuels? How might you limit those activities?

CROSS-CURRICULAR CONNECTIONS:

LANGUAGE ARTS: The mascot of the school in Gambell, Alaska, is a legendary polar beat called qughsatkut. "Qughsatkut" is the Siherian Yupik word for king polar bear. Write a poem about polar bears in haiku, which consists of 17 syllables arranged in three lines of 5, 7, and 5 syllables each.

RESOURCES

* Advanced readers and teachers may enjoy reading this inspiring book: Kids From Nowhere by George Guthridge, Alaska Northwest Books, 2006. In the 1980s, author George Guthridge was a teacher in Gambell, Alaska. While there, he coached his students to a stunning victory in a national academic competition.

* Visit this site from the Alaska Native Heritage Center to learn more about the customs of traditional St. Lawrence Island Yupik: www.alaskanative.net/36.asp

* Learn more about the culture and history of Alaska. Check out this Web site of online exhibitions from the University of Alaska's Museum of the North: www.uaf.edu/museum/exhibit/virtual.html

DIRECTIONS: Answer the following in complete sentences.

1. The Siberian Yupik living on St. Lawrence Island, Alaska, are subsistence hunters. What do they hunt?

2. Why do the Siberian Yupik oil St. Lawrence Island hunt?

3. What causes global warming?

4. How does sea ice that melts earlier than usual around St. Lawrence Island affect the people living there?

5. What was the hypothesis of Bobby Ungwiluk's science project? What was the result of his experiment?

ANSWERS

1. For survival, the Siberian Yupik living on St. Lawrence Island. Alaska, hunt--while following strict government hunting guidelines--for walruses, seals, bowhead whales, and other animals.

2. The Siberian Yupik live in a remote and icy environment. They rely on the animals they hunt--as well as the few plants and berries that manage to grow in the harsh environment--to provide them with the nutrients they need to stay healthy. Other foods like bread, milk, hamburger meat, and canned vegetables are flown onto the island from mainland Alaska, but the goods are very expensive.

3. As people around the world burn fossil fuels like coal and oil to power their homes, factories, and vehicles, they release heat-trapping greenhouse gases into the atmosphere. As these gases build up, they insulate the planet As a result, Earth's average temperature rises--or global warming.

4. Sea ice that melts earlier than usual around St Lawrence Island creates conditions that are dangerous for Siberian Yupik hunters. The hunters could fall through thinning ice, or even get trapped by the ice as it shifts with the wind or sea currents.

5. For his science project, Bobby hypothesized that seas heated by global warming would be slow to cool down even if greenhouse gases were reduced. His project's results proved the hypothesis true.