We don't understand what photography is doing. We don't understand the power of its rhetoric. We don't understand why the Provoke photographers showed Tokyo city as a ghastly and alien city when it was really going through this period of mega-capitalist growth. It's a very, very, very powerful force, the photograph. People ask me why it has such an ability to captivate us. And I just don't know.

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.

There was a time, right up until the end of the Second World War and beyond, when white people in Europe thought that they basically owned the world and that everybody else was a sort of servant, or a curiosity, or whatever. And that informed 99 percent of the photographic practice that was done. Without being able to address that, I felt I would have failed in my attempt to explain what the urge to document is.

Newspaper photographs nowadays are highly tautologous. You'll have an article about, say, stopping the war. And the photograph that will be used is literally a poster that reads "Stop The War." Or you'll have a story about a cash crisis in Barcelona, and the only picture you'll see is an ATM in Barcelona. The problem is actually systemic. On the one hand, you'll have a picture of a soda can to "illustrate" an article about the dangers of sugary drinks. On the other hand, anything that's reasonable in documentary photography is snapped up by the art world and we never see it.

There is a danger in our modern practice of using embedded journalism. As there is less and less money available for journalism to uphold its independence, there is a temptation for people to take short cuts. If this army or that army or this corporation is willing to pay for your flight or your accommodation, then it's much more difficult to tell what the real story might be. I do have a concern about that.

Photography was increasingly being seen as something outside the art world. As a sort of illustration. They just fired the director of photography at the Sunday Times Magazine - that's where everyone went with their photo essays in the '60s, '70s, and '80s. It was the place to get published. It is an issue. And I feel it. There's no budget. The budget-holders are very often people who've been to the professional colleges where art is not taught. So art as a part of education is something that's missing - since Thatcher's day, anyway.

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.