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.

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.

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.

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.

I think, oddly, that the world of the amateur is quite self-contained, and it depends on "likes" from other amateurs to perpetuate itself. Of course an awful lot of my colleagues are involved with Instagram - they get likes and dislikes, maybe just likes, I don't know - but I think that it's far less self-contained, the world I work in. It goes off in different directions, and is dependent on responses different from a tick or a like or whatever.

After my mother died, I lived with relatives. Reading was a means of escaping into other worlds, as photography, much later, was to become.

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.