Eric Larsen, 40, is the first person to have reached the South Pole, the North Pole, and Mt. Everest's summit within the span of one year. He spent 48 days traversing Antarctica, 51 days trudging the Arctic, and 45 days conquering Earth's highest peak before coming home to Boulder, Colorado, in 2010.

He blogged and tweeted the entire way for his Save the Poles project, whose goal is to get people to care—and do something—about climate change.

Q: WHERE DID YOU GET THE IDEA FOR THIS JOURNEY?

A: At the end of an expedition in 2006, when I was at the North Pole in summer. I was surprised to see more water than ice, and I realized that my next trip could inspire others to act.

Q: HOW DID IT FEEL TO GET TO THE TOP OF EVEREST?

A: I was relieved, actually. And I didn't feel totally relieved until I got down to base camp.

"When climbing Everest, I thought, 'You know what, we probably aren't gonna make this.'"

Q: AWE OR GLORY OR ANY OF THAT?

A: I was in a constant state of awe. It was balanced with stark fear. But for me, the physical end of the trip is anticlimax. I don't feel like, "Oh, I'm so tough." It's more, "I'm just amazed I was able to pull it off." It's definitely more about the journey and the things I learned along the way. The summit or the pole, those just define the trip and give the end point.

Q: DID YOU SEE OBVIOUS SIGNS OF CLIMATE CHANGE?

A: Yeah. I had done that previous trip to the North Pole, so going back there, I was very surprised. The ice had changed dramatically. It was thinner and rougher and lifted up more easily. It's concerning because polar ice caps are integral in regulating the world's climate. As they change, so does the rest of the planet. In the Himalayas, all the Sherpas talk about it: the Khumbu Glacier retreating, the ice pinnacles shrinking, and definitely weather patterns changing.

Q: WHAT WAS YOUR MOST IMPORTANT PIECE OF GEAR?

A: As silly as it sounds, maybe the satellite phone. Even though I could have done the trip without it, I couldn't have shared my story, which was my biggest goal.