Low Carbon: Reaching for the sky

Lumbered together with endless tonnes of steel, glass, concrete and precious metals, skyscrapers are, Yeang admits, "probably the most ecologically unfriendly of all building types".

But until we find better ways of living and working, skyscrapers are with us to stay. So just how, exactly, can we make them as humane and sustainable as possible?

THINKING OUTSIDE THE (TALL) BOX

We think of them as the plaything of King Kong, or of towering over our capital cities with their steel-and-glass designs, but skyscrapers have been around for a long time - they just had a different name. The Great Pyramid at Giza, built around 2650BC at nearly 500 feet, was the tallest building in the world until the 14th century, when Europe started to catch up with its campaniles, forts and towers.

Today Taiwan boasts the world's tallest building - the Taipei 101, standing at 1,670ft - which will soon be surpassed by Dubai's 2,700ft-tall Burj Tower when it's completed this year in September. Boasting 162 floors, the Burj Dubai will be a multi-use building made out of glass and concrete, and has been specifically designed to attract tourists to the desert city - for business, not ecological, purposes.

The inherent problem with skyscrapers is that they are highly energy inefficient. Sure, they might save space, but building up actually requires one-third more energy than building across. Cooled all day and lit up all night, they need constant supplies of electricity, reflect heat back into our cities and lag behind on even the most basic of green steps like recycling.

But as architects across the world seem to have developed Napoleon complexes, turning the competition from the world's tallest skyscrapers into its greenest might do us some good.

"Our future will be won and lost in our cities," explains the soft-spoken Yeang, who was recently voted by the Guardian as one of the 50 people in the world who could save the planet.

"That's where we have the highest concentration of people and buildings, so we need to make them as green as possible. And that means looking at the way our buildings use, and exude, energy."

Yeang is all about bio-integration - using architecture to mimic nature's forms and methods. That means looking at the way a building uses its energy, how it gathers its water, if it can provide food for the people in it, and how it heats and cools itself.

"In nature, there is no waste," explains the architect, whose key works include the spiral-gardened and solar-powered Menara Mesiniaga tower in Malaysia, and the Great Ormond Street hospital extension in London.

"A concrete structure is inanimate and completely detached from nature, whilst an eco skyscraper, which includes vertical landscaping, can help bridge the gap between nature and the built environment."

'Vertical landscaping' is a fancy term whereby plants are used not only for their ecological and aesthetic benefits, but also to cool buildings. Designed to face outward or inner courts of upper parts of tall buildings, the plants absorb carbon dioxide and generate oxygen, benefiting the building and its surroundings.

VERTICAL FARMS

While some buildings already boast vertical landscaping - see Paris's Musee du Quai Branly for a taster - what Yeang wants to see better incorporated into our buildings are vertical farms.

"We have a worldwide food problem, with an increasing number of mouths to feed and fewer means of actually feeding them," he explains. "Turning our skyscrapers into vertical farms turns urban land into productive centres for agriculture."

Growing food indoors isn't anything particularly new - the many hothouses and conservatories that dot our landscapes prove as much - but using skyscrapers and buildings to help feed the 3 billion people that now live in the world's cities, is.

"Bringing vegetation into buildings softens their hard syntheticness and inorganicness," explains Yeang.

"It improves the ambient temperature of a city by reducing its heat island effect [whereby the city is significantly warmer than the surrounding countryside], improves the local microclimate because the plants absorb CO2 and give off oxygen through photosynthesis, provides insulation between the inside and outside and helps promote biodiversity."

One vertical farm that has already taken off is located smack in the middle of Tokyo. Human resources group Pasona installed a 930 square foot farm in the midst of its office, turning six rooms into rice paddies and strawberry, tomato, lettuce and daisy fields run by computer-controlled lighting and temperatures.

But vertical farms don't just help feed us, they help heal us too.

"Studies have shown that patients in hospitals with green walls and gardens heal faster than those who look at concrete walls," explains Yeang. "It's a system called 'biophilia'."

Yeang's Children's Medical Centre at Great Ormond Street Hospital (pictured), scheduled for completion in 2011, addresses the benefits of biophilia by boasting green roofs, water-saving devices, and natural ventilation systems that diminish the need for constant air-con.

The development - which will comprise one new clinical building and revamp of the old cardiac wing - will offset around 20,000 tonnes of CO2 a year, achieving a 20% carbon emission reduction for the whole hospital.

INTRODUCING... NATURE

So if the benefits are so clear, why aren't more buildings going green? In a word: cost.

"Most developers have not yet got to grips with sustainability," says Yeang. "They still think 'sustainability' means putting gadgets into buildings like photovoltaics and groundsource heatpumps. The next generation of green architecture will have to be a whole host of things apart from conventional buildings with eco add-ons."

While Yeang encourages building new and building greener, he's weary about a collective inertia that could prevent us from upgrading our existing buildings into eco-friendlier ones.

"Converting our stock into greener buildings is more pressing than building new," he says. "The French government started to demolish and rebuild many of their high-rises in order to bring them up to energy standards, but we know now we can retrofit them to the same standard without having to tear them down - and all for the same price."

Recycling existing structures and building newer green ones will be more possible by tax breaks and grants, or the allocation of penalties, which the Government should all have a hand in, Yeang says.

But the future of buildings also depends on public attitude toward them - and that means that we need to wisen up, fast.

"We always had a cavalier attitude toward nature until we became aware of the impacts of climate change and the increasing natural disasters that have impacted many human communities," he says.

"All these have made society become more aware of the need to coexist harmoniously with nature rather than to recklessly dominate it without concern for its impact."

Let's just hope it's a lesson learned - and not too late.