Global warming: What is global warming--and how can we slow it? (USA/Environment).

Brrh! Adelie (ah DAY lee) penguins like it cold. They even make their nests out of pebbles!

These cool creatures have lived on the Antarctic Peninsula, on the world's chilliest continent, for centuries. But since the 1950s, as global temperatures have risen, the volume 'of sea ice at the South Polar Region has shrunk 20 percent. At the same time, the Adelie population in Antarctica has been cut in half.

Sound fishy? It turns out that the shrimp-like krill the Adelie feed on don't like warmer climates. As their population has decreased, so have the Ade1ie.

If the warming trend continues, scientists say, the world's food chain could be disrupted far beyond Earth's icy poles.

Already, the reports are alarming:

* Glaciers around the world are melting at ever-increasing rates.

* Rivers and lakes in North America, Asia, and Europe now freeze about 9 days later and thaw 10 days earlier than they did a century ago.

* And the inhabitants of Tuvalu, a tiny string of islands in the South Pacific, may have to find another home soon. Rising ocean water is slowly swallowing up their remote country.

Trapping Sun's Heat

What has caused this warming trend? Some scientists believe that it is merely the result of natural cycles in the Earth's climate. The continual warming and cooling of ocean currents, for example, or changes in the sun's brightness can affect these patterns.

But most climate experts now agree that global warming has human fingerprints all over it. We burn fossil fuels--coal, gas, and oil--to run cars, heat buildings, and power factories. The U.S. consumes more petroleum than any other nation.

This process spews carbon dioxide ([CO.sub.2]), methane, and other waste gases into the atmosphere.

These gases create a greenhouse effect: They trap the sun's heat in the Earth's atmosphere, just as a greenhouse holds the sun's rays.

Most experts believe that burning fossil fuels is the main cause of global warming. The destruction of rain forests (see sidebar, p. 11) and increases in mining and agriculture also add to the problem.

No More Snowballs

The 1990s were the warmest decade on record. (Global temperatures were first measured in the 1860s.) Scientists now expect average temperatures to rise between 3 to 10 degrees Fahrenheit over the next 50 years.

That may not sound like much. But the average temperature during the last Ice Age, about 10,000 years ago, was only about 9 degrees Fahrenheit cooler than average temperatures today.

It may seem great to have warmer weather, especially in the winter. But unless we make efforts to slow global warming, we could face serious consequences. Scientists say that more extreme weather events, and an increase in major floods and droughts, are likely if temperatures continue to rise. Higher temperatures could also further the spread of disease.

"Greenhouse gases have a life of 100 years or longer," Ben Santer, an atmospheric scientist, told JS. "That's why the problem is so serious. Even if one could restrict emissions to 1990 levels, the stuff will be there a long time."

Kyoto and Beyond

What is the solution? In 1997, 160 nations gathered in Japan to draw up the Kyoto Protocol. This treaty would require 38 wealthy industrialized nations, including the U.S., to cut their emissions of [CO.sub.2] and other heat-trapping gases by the year 2012.

But many people in the U.S. did not agree with the Kyoto treaty U.S. critics were unhappy because it exempts poorer nations, like China and India, from having to cut their emissions. These nations also produce significant amounts of [CO.sub.2].

U.S. critics say that exempting these countries--which have rapidly growing economies--could put the U.S. economy at a disadvantage.

The Bush administration has argued that the cost of going along with the Kyoto treaty, including developing new technology and cutting back on emissions, is too high. As a result, President Bush has refused to sign the treaty.

But in February, he announced a new plan. The President will ask companies to volunteer to emit fewer heat-trapping gases. If this voluntary approach does not work, then the plan will be re-evaluated in 2012.

"We do a whole lot better," says Christine Todd Whitman, head of the Environmental Protection Agency, "when we can get corporations to willingly step forward and [cut] greenhouse-gas emissions, than for us to put in place a regulatory process."

Environmentalists fear that even if businesses comply, the amount of emissions will still go up.

"Energy Security"

Since September 11, one of President Bush's biggest concerns has been what he calls "energy security"--making sure that the U.S. has enough energy to get through a crisis.

"Dependence on foreign oil is a matter of national security," he said recently. "To put it bluntly, sometimes we rely upon energy sources from countries that don't particularly like us."

To meet our energy needs, Bush wants to build thousands of power plants, use more nuclear power, and drill for oil in the Arctic National Wildlife Refuge.

But must there be a conflict between meeting our energy needs and protecting the environment? Many environmentalists argue that conservation and new, cleaner technology can help meet our goals of security, prosperity, and a cleaner atmosphere.

Relying more on solar and wind power and less on oil, for example, could help conserve our energy supply. And more hybrid cars (seep. 11) could replace gas-guzzling SUVs.

"What we're talking about is moving toward cleaner ways of living," says Paul Fain of the Union of Concerned Scientists. President Bush also favors investing in research for more efficient cars.

Turn Out the Lights!

Most climate scientists agree that we must act now to slow global warming. Here are a few simple things that you and your family can do:

* Turn off the lights when no one is in a room;

* Buy energy-efficient appliances, such as those with the Energy Star label;

* Walk short distances rather than ride in a car.

"If we wait and do nothing [about global warming]," says Ben Santer, "that doing nothing is a decision, and it is a risk." [JS]

Web Environmental Protection Agency: www.epa.gov/globalwarming/climate/

[Graph omitted]

Goodbye to State Birds?

Imagine Baltimore without any orioles (the birds, not the team).

The National Wildlife Federation and the American Bird Conservancy warn that seven state birds may soon be endangered.

A recent report says that these states could lose their state birds:

Maryland       Baltimore oriole
California     California quail
Georgia        brown thrasher
Iowa           American goldfinch
Massachusetts  black-capped
               chickadee
New Hampshire  purple finches
Washington     American goldfinch

These birds have been seen less and less in the U.S. in recent years. Scientists say that one reason is because the birds' migration patterns are changing. Another reasons is that their natural habitats--places where they live and breed--are being destroyed. Global warming may be partly responsible for both changes.