Better use of space, improving the insulation, getting more daylight into the buildings, reducing the energy consumption of the air conditioning and heating systems, making sure that the internal air quality is good, that we have increased natural ventilation opportunities in the mid seasons. You know these are some of the things we can do.

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.

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.

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.

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.

In nature the only source of energy is from the sun. So in ecological systems everything comes from the sun through the process of photosynthesis whereas now in human built environment our source of energy is from fossil fuels, renewable, wood energy or hydro-energy but it is not from the sun. So until we are able to operate and run a human built environment by imitating photosynthesis it will be a long while before we can have a true eco-system.

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.