The cumulative effect of each person making a change in his or her own life will make a difference.

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 cumulative effect of each person making a change in his or her own life will make a difference.

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.

You can't divorce civilization from nature - we totally depend on it.

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.

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.