A volunteer group of Seattle-based engineers is working on an innovative solution to the problem, one that also will provide a big energy benefit. Earlier this month, they completed a design for a biogas reactor to convert climbers' feces into methane gas to serve as a cooking fuel for the Sherpa villagers. Construction could begin as early as next year. If it is a success, the Mount Everest Biogas Project will be the world's highest-elevation biogas reactor and proof-of-concept for an invaluable tool to protect iconic high-mountain ecosystems. (See related story: "Maxed Out on Everest: How to Fix the Mess at the Top of the World" and photos from the mountain.)

The genesis of the idea was a