This segment was originally broadcast on April 1, 2007. It was updated on Aug. 14, 2007.
If you were waiting for the day global warming would change the world, that day is here. It's happening, far from civilization's notice, in a place about as remote as you can get.
Scientists believed Antarctica, at the bottom of the world, was too vast, too remote, to be bothered by climate change any time soon. But now glaciers are setting speed records for melting and whole colonies of penguins are disappearing.
Why does it matter?
Antarctica is a climate giant, driving ocean and wind currents worldwide, with enormous potential to raise sea levels.
To find out what's happening down south, 60 Minutes correspondent Scott Pelley set out on an expedition; the first stop was the high mountains of Patagonia in Chile, where you can actually see a new age beginning.
The glacier O'Higgins, a mass of ice, has been frozen for tens of thousands of years in the mountains of southern Chile.
O'Higgins is spectacular for its beauty, but for a scientist like Gino Casassa it's breathtaking for the speed it is disappearing – the glacier is morphing into a lake, retreating more than any glacier in South America.
The location where Pelley interviewed Casassa was covered by ice a hundred years ago. "I think it's a very clear picture that the world is getting warmer and that the impacts that were projected even 10 or 20 years ago are happening right now," Casassa explains.
The glacier has fallen back nine miles in 100 years, throwing off icebergs that roll, as they dissolve into the lake.
Casassa took Pelley and the 60 Minutes team to the face of O'Higgins, carefully measuring their approach; the glacier is a dynamic thing, cracking, popping, and changing, as huge pieces break off.
Photos: Go behind-the-scenes with 60 Minutes in Chile and Antarctica
Casassa is a glaciologist, who surprised 60 Minutes when he revealed what he used to think of global warming. "I just didn't believe in global warming. I mean in global warming being produced by mankind, by us contaminating the atmosphere, I just refused to believe that," he explains.
He says, now, the evidence has convinced him. Pelley set out to find more evidence, as Casassa went to measure the height of O'Higgins. The 60 Minutes team climbed to a spot where Casassa had crossed from earth to ice in 2004. But now, in 2007, that spot was covered by water.
Much to his surprise, there was a thousand feet of water where he had walked three years ago. The group had to hike for hours to get to the ice. When they got there, they found it blackened by earth and volcanic ash. Casassa set up a receiver to measure the distance from the top of O'Higgins to satellites overhead.
He measures the distance to get a contour line at the top of the glacier. "As we walk, the receiver, which is in my backpack, is capturing data every one second," Casassa explains.
And the data showed Casassa that glacier O'Higgins has thinned 92 feet in seven years.
And it's not unique. More than 90 percent of the world's glaciers are retreating. And if you're looking for early trouble from climate change, this is it. Glacial runoff provides water for 1.5 billion people, mostly in South America, China and India.
"In the medium term, depending on the size of glacier…30 years, just a few decades, the glacier will start to waste away in such a degree that you will see the runoff the glacial melt coming from that glacier starting to decline," Casassa says.
Cities around the world, says Casassa, will be starved for water. And he says we now are seeing the first impacts.
60 Minutes wanted to see the evidence of warming nearer the bottom of the world. So Pelley and the team set sail from the last city south, Ushuaia, Argentina, on a two-day voyage to Antarctica.
It is more than 1,000 miles from glacier O'Higgins in Patagonia and across the Drake Passage to the Antarctic peninsula.
Here, 60 Minutes found there's green where the white used to be; on the coast, in summer, there's grass where the scientists used to ski. The area is called "Paradise Cove," and it is home to fur seals, lazy elephant seals and the Chinstrap penguin.