I think green buildings are extremely important but it's only part of the equation. A lot of people think that if I put a green building everything is going to be fine, but actually it's not just the green buildings we need, but green businesses, green governments, green economics. We have to extend the greening of buildings to our business and our lifestyles - that is the most important thing to do next.

The ecologist has a much more comprehensive and holistic view of the world. We're looking at the natural environment as well as the human built environment and the connectivity between the two - how do the natural environment and the human-built environment interact and interface with each other.

In my heart I believe that biology is the beginning and the end of everything. It's the biggest source of ideas, the biggest source of invention. Nobody can invent better than nature and so if you like nature is my biggest source of inspiration.

If you look into the way that materials are used in an ecological system you'll notice that you'll find that there is no waste. The waste of one organism becomes food for another and everything's recycled in an ecological system whereas in our human built environment there's a throughput system. We use something then we throw it away... We have to imitate nature and try to re-use everything we make as human beings or recycle them - when we cannot re-use or recycle them we should try to reintegrate them back into the natural environment.

In most ecological systems you have a composite, biotic components as well as abiotic components acting together to form a whole, whereas in a human built environment most of the components are abiotic or they are inorganic. One of the first things we need to do is to complement the inorganic components with more organic components, and to make them interact to form a whole.

We shouldn't just look at new buildings but at existing stock building because that's an even greater problem than the new buildings being built. The renovation of existing buildings and making them green is just as important as designing new green buildings.

I think buildings should imitate ecological systems.