Environmentalism is a personal thing - but it's also a planetary thing. It's about making deep connections. But it's also about recognizing the very human connection between species diversification and ourselves.

We sort of understand how painkillers work. You take one, and it reduces your headache. We don't understand how photographs work. And that, to me, is an essential problem as a practitioner.

There's an awful lot of work being done that no one ever sees, or that is only seen in the gallery world. I feel that the public are losing touch with the great stuff that's being done in photography.

In the same way, photography, for me, has fragmented. You do have people doing bodies of work - often with found photographs - that are quite hard to understand unless you got a very sophisticated visual history behind you. But there are different camps.

The world of photography is very self-aware. Everybody is always looking around. So it's quite difficult to stand up with a megaphone and declare, "This is what I think." As a reasonably shy person, I found it difficult to do that.

As humans, we need to question all these notions. What does freedom mean for us? What are our responsibilities? It takes one-250th of a second to take a photograph. So I have the whole of the rest of that second - and of that day - to think.

There was as big a reaction after the revelations about Assad's chemical weapons. Nevertheless, that photograph did strike a singular chord. Which leads us to a larger fact: we don't understand why certain photographs create such an upheaval in one's soul. You look at them and go, "Oh my gosh." And that doesn't happen with television. It's unique to photography. Photographs are unique in that they are a frame abstracted out of reality, out of, in this case, a civil war. A single event can carry so much weight. And that is extraordinary.