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.

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.

I was raised a Catholic as a boy and went to a Catholic boys' high school, a private school, and kind of drifted away, candidly, in my latter teen years. I consider myself deeply spiritual but not in an institutional, religious kind of a way. In Catholicism, we're surrounded by these images of martyrdom and doing penance and doing some suffering to achieve what you're trying to achieve. And I certainly embedded that in my psyche and I have lived that very effectively.

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.

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.

I've been to the Himalayas a half a dozen times and I love it. I'm just kind of tired of going literally twelve time zones around the world. I would rather go six time zones and get to Iceland or whatever it is.

There is a glacier in Iceland, Solheimar, which has retreated a great deal, and every time I go back there and see what's not there any more, it does something to the heart. It makes you realise it's possible for a gigantic natural element to just disappear.