Londoners have affectionately dubbed the Swiss Re Tower 'the Gherkin' for its uncanny resemblance to a giant pickle on the city skyline. The global reinsurance company - which has taken a lead in calling attention to the dangers of climate change - made its words concrete when building its offices. The 180-metre tapered glass tower, which rises above a ground-level plaza of restaurants, shops and cafes, is within easy walking distance of public transport and uses 50 per cent less energy than a conventional building of similar size. Upwardly spiralling light wells circulate fresh air and natural lighting throughout its 40 floors, and exterior weather sensors monitor outside temperature, wind speed and sunlight levels, closing blinds and opening window panels as needed.

photo: Nigel Young/Foster and Partners

The 12-storey glass tower Edificio Malecon is one of the most technologically advanced office buildings in Buenos Aires. It stands on a reclaimed brownfield site of old industrial land: its parking garage is built within the foundations of a 19th century warehouse. Its long, narrow shape and orientation from east to west are designed to minimize the amount of solar heat trapped during the hottest times of the year, while mechanized sunshades and windows deflect excess sunlight and harness cooling breezes from a nearby river. High performance, lightweight exterior panelling forms a glass curtain wall to protect the building from the elements while providing wide views from every angle.

photo: Daniela MacAdden/Hok Sustainable Design

Menara Boustead, the Kuala Lumpur headquarters of the international information and technology company IBM, is an energy-saving skyscraper that aims to make use of the tropical climate. Windows and glass curtain walls maximize natural lighting throughout its offices and meeting rooms, as well as lobbies, lifts, lavatories and stairwells. A specially glazed curtain wall prevents the building's 30 floors absorbing excessive solar heat, while external fins and adjustable slats provide shade from the sun. Skycourts, terraces and atriums house plants and other greenery, increasing the supply of oxygen and sending natural ventilation through the building's core.

photo: T. R. Hamzah & Yeang Sdn Bhd

The low two-storey Green Building, in Cape Town's Westlake Business Park, is built from recycled, local concrete brick and sustainably harvested wood, and boasts a passive thermal design that eliminates the need for air conditioning. If needed, the building can be flushed with cool night air through two chimney ducts linked to concrete pipes running underneath the ground floor. Roof-mounted photovoltaic (solar cell) panels turn sunlight into electricity, while a separate solar power system heats water for kitchens and bathrooms - including showers for those who cycle to work. Drainage systems channel household 'grey' wastewater and rainfall into surrounding fruit and vegetable gardens.

photo: Mike Schroeder, Cape Town

Another innovative green building - the Reichstag in Berlin - is featured in the 7 City Wonders on page 22.