In the documentary impulse, two species of 'fact' exist side by side: one is coolly objective and the other is fraught, diverse and emotive; one figurative, the other abstract; one prosaic, the other poetic; one factual, the other romantic.

I have a huge respect for the dedication that many people have, on the other side of the Atlantic, to photography. You can count them on one hand here. There's less respect for a Magnum photographer in Britain than there is in America. It's a much more postmodern culture here.

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.

Social media's currency is the single photograph. Whereas, every time I look at a photograph, I look at twenty or thirty photographs. I'm looking for a narrative. And that's a different kind of construct. If you're a poet and you put a line from your poem online, "The trees bending over gracefully," or something, you can get a tick. But that has nothing to do with your longer poem.

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 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.

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.