The 'New Yorker' asked me to shoot a story on climate change in 2005, and I wound up going to Iceland to shoot a glacier. The real story wasn't the beautiful white top. It ended up being at the terminus of the glacier where it's dying.

Glacial pace is actually an incorrect concept. The glaciers move a lot faster and they react a lot faster than people imagine.

In some cases, I allow the edge of the set, the edge of my own artificial, artistic imposition, to show up because I don't want to hide from that. I want to acknowledge that there is a living human and a living eye and a living mind and a living heart responding to what's going on out there.

Each of us can and must shift our behavior according to our ability. For some, that means changing diet, shopping locally, or putting solar panels on their house. For others, it means using their voice to inspire transformative change.

The problem is almost everybody is just recording the world with home photographic toys, not doing metaphor or ideas. We have a photographic culture that's not conditioned to think in terms of symbol.

Ultimately, we have to ask ourselves an essential spiritual and ethical question: Are we the kind of people who take everything for ourselves and leave nothing for others, or do the angels of our better nature still live? I believe the angels are still alive.

I have often thought that my work with wildlife taught me the meaning of patience, and my work with the big trees taught me the meaning of humility, and my work with the ice has taught me the meaning of mortality.