I have to understand the nature of change. And I cannot just work with stone or the more permanent materials. I need to work with leaves and ice and snow and mud and clay and water and the rising tide and the wind and all these.

The relationship between the public and the artist is complex and difficult to explain. There is a fine line between using this critical energy creatively and pandering to it.

Winter makes a bridge between one year and another and, in this case, one century and the next.

Some of the snowballs have a kind of animal energy. Not just because of the materials inside them, but in the way that they appear caged, captured.

I have worked with this red all over the world - in Japan, California, France, Britain, Australia - a vein running round the earth. It has taught me about the flow, energy and life that connects one place with another.

Generally in New York, people just walk over you with no problem about that. Other countries, people want to resuscitate you, like, after a bit.

The main reason I went to digital was because I got time-lapse, video, and still images all in one camera. Having a minimal amount of gear is really important for someone who wants to walk around. That allowed me to have this flexibility to document things in different ways.