Last night I slept on the slopes to Tungurahua, a highly active volcano in Ecuador. I felt the earth shiver, heard her rumble, and smelled her smoke. I was very conscious that this earth of ours, our home – what the local Quichua people refer to as Pachamama – is truly a Living Earth.

A few days earlier I had travelled down the Avenue of Volcanoes, also in Ecuador, and had passed by another mountain, one that is barren, scarred with gullies, and ravaged by erosion. I remembered the time whe...