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A decline in sea ice may be Antarctica's biggest change RELATED VIDEO CNN's Marsha Walton reports on Antarctic climate research Real 28K 80K Windows Media 28K 80K Antarctic scientists study tiny krill for evidence of global warming Real 28K 80K Windows Media 28K 80K

(CNN) -- It's a hot topic for debate among scientists and politicians: Is global warming really happening? Some researchers in Antarctica say they've got the cold, hard facts.

Ecologists have predicted for at least three decades that when climate warming occurred, it would first be measurable at the poles, namely the Arctic and Antarctica, says research scientist Bill Frasier of Montana State University.

"Indeed, that's precisely what we're seeing," Frasier says.

Frasier is working with satellite mapping experts to find out how a 10 degree-rise in winter temperature is affecting Adelie penguins. He's tracking the annual decline of Adelie colonies as increased moisture and resulting snow destroy their nesting habitats.

"These penguins are, in fact, the ultimate canaries in the mine shaft -- extremely sensitive indicators of climate change," he says.

On Stepping Stone Island, Arizona State professor Tad Day is studying Antarctica's only two flowering plants, hair grass and pearl wort.

Frazier studies Adelie penguins

Day has discovered that under warming conditions, pearl wort is likely to replace hair grass as Antarctica's dominant plant.

The biggest change in Antarctica may come with the decline of winter sea ice.

"What we've seen in the last five decades or so is an actual decrease in the number of years with heavy sea ice," Frasier says. He says the change has been particularly marked in the current year.

The scientists hope the lessons they're learning in Antarctica will help them spot and understand climate change in the rest of the world.

Correspondent Marsha Walton contributed to this report.

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