Mountains are freedom. Treat them respectfully.

If people want to go do some big outdoor thing for their ego, have them climb snowy mountains rather than shoot animals.

The mountains are a demanding, cold place, and they don't allow for mistakes.

The mountains seem to have conquered us long before we set foot on them, and they will remain long after our brief existence. This indomitable force of the mountains gives us humans a blank canvas on which to paint the drive of discovery and, in the process, test the limits of human performance.

The alpine environment is very delicate. I've been able to see change in the mountains in the 20 years that I've been climbing full-time. Glaciers have receded. The tree-line is changing. That's very rapid to see nature changing in a 20-year period.

If you compare Everest photographs in 1953 with its current state, things are melting. I imagine if I were a golfer in Indiana, I'd be hard-pressed to believe in climate change because nothing's going on there. But when you're up in the mountains and seeing the glaciers melt away, it's an obvious physical manifestation of a warming planet.