I've got at least two major project ideas that I've been chewing on for several years in my head and I've been trying to resist them both. But I have learned over the years that when they don't go away and they're still in there, you probably have to resign yourself to the fact that you're going to do something about them.

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.

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.

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.

When I worked with wildlife a lot in the Eighties and Nineties, I learnt the meaning of patience. And when I worked with trees, I learned the meaning of humility.

Early in my career I discovered that there was something really special about photographing at night that places your mind on the surface of the planet. You’re no longer just a human being walking around in the regular world. You’re a human animal striding around on the surface of the planet that’s out in the middle of the galaxy. We as a culture, we’re forgetting that we are actually natural organisms and that we have this very deep connection and contact with nature. You can’t divorce civilization from nature. We totally depend on it.

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.