Once only the domain of hippies and eco-warriors, green or environmentally friendly building is emerging as a multi-billion-dollar global business, driving technical innovation in the fields of architecture and construction, and creating a broad range of new "green-collar" jobs across the planet.

Driven by escalating energy costs and stringent new government legislation, green building is currently experiencing a profound shift, from "greening" existing structures towards creating Net Zero buildings - structures that will generate more energy than they require to operate over the course of a year.

The Hearst Tower was the first skyscraper in New York City to be awarded Gold status under the US Green Building Council's Leadership in Energy and Environmental Design (Leed) rating system, and while it still falls short of the Net Zero milestone, it represents a significant step forward for the industry.

By swapping the grid format of the building's external structure for a diamond design, the construction used significantly less materials than similar-sized buildings, while optimising the amount of natural light that filters into the internal spaces. Of the steel used in the tower's construction, 80% was from recycled sources, while the interior was fitted with recycled carpets and bamboo flooring. The tower also collects 50% of its water needs from rainwater.

The Hearst Tower is leading the charge towards a greener built environment, with future international building projects aiming to generate their own power by incorporating wind turbines and photovoltaic cells into the structures. But the situation is somewhat different in South Africa.

While there are an increasing number of eco-friendly building materials available in the country, many of these products are stuck in the approval process, and cannot yet be incorporated into new buildings. Substitutes for major environmentally destructive materials such as concrete and aluminium are still a way off from being commercially available here. The Sans 204 legislation that will ensure better energy efficiency in new buildings has also yet to be tabled, despite being in process since 2007.

Despite this, the Green Building Council of South Africa has certified seven new buildings as green since 2008. The most recent recipient is the MacNab building in Parkwood, Johannesburg, which incorporates solar cells, natural light and recycled materials in its design, and omits materials with toxic organic compounds from the construction.

While interest is growing among South African corporations, uptake in this area has been relatively slow - mainly as a result of the prohibitive costs involved. The situation is worse for residential construction, as the cost of truly green building renders it almost unattainable for most people looking to build their dream home.

For example, reticulated under-floor heating can cost as much as R200000 to install, compared to standard under-floor heating that can cost as little as R2000 per room.

But not all green solutions need to be high-tech and expensive. Simple tweaks and intelligent design can make significant improvements to a building's environmental impact and energy efficiency.

While heating is less of an issue in South Africa with our relatively mild climate, energy costs are set to sky-rocket, which means proper planning is critical in order to maximise energy use.

Orientation in relation to the sun is critical for minimising the need for internal lighting, as is improved structural shading to cut solar heat gain in homes and maintain a comfortable living environment.

Solar is still massively expensive and unlikely to become more affordable in the near future - but grey water systems, rainwater tanks and solar geyser systems are more affordable and easy to install.

But green building is not simply concerned with structures; it's also about living and working in a more responsible manner.

This concept of "deep green" is rapidly gaining traction, with eco-communities sprouting across the US that combine housing and recreational spaces with commercial and retail facilities within walking or cycling distance of one another, alleviating the need for large-scale transport systems.

In this regard, South Africa faces some major hurdles, partly as a result of our history of segregation.

Generally, only the most affluent are able to live within a reasonable distance of their place of work, with the majority having to commute long distances from outlying townships - a situation that is replicated with the massive townhouse developments being erected on the outskirts of our major cities.

Truly green building in South Africa will see not only the incorporation of intelligent design and eco-friendly materials, but the creation of true urban communities capable of supporting sustainable city living.

Whether the houses are square or in the shape of igloos, made of bamboo, straw bails or sandbags remains to be seen. But what is essential is that they support healthy, productive communities that are far more intimately integrated into society.