BUILDING FOR A COOLER CLIMATE

Buildings account for more than a third of the energy used on the planet. By far the biggest impact on the climate comes from the way buildings are used once they are constructed, and there is huge potential to reduce this footprint through better design, smarter choices for meeting the energy needs in buildings, and to integrate these every time a new building is constructed or an existing building is renovated.

Construction does, of course, involve substantial greenhouse gas emissions, and a large proportion of these are embedded within the materials used. The leading construction company Skanska, for example, estimates that between 80 and 90 per cent of its emissions (not including the use of the building once it is finished) come from beyond its direct activities and electric- ity use—and of these so-called “Scope 3” emissions, between 60 and 70 per cent are attributed to steel and concrete.

With some 12,000 projects started each year, this makes the footprint of a company like Skanska a complicated one, and it is currently working on a “first-cut” estimate of the emissions from producing the steel and concrete used in 2009.

The Arendal divison of Skanska Norway is a member of the UNEP Climate Neutral Network, and for now it is concentrating its efforts on reducing the emissions over which it has direct control—such as ensuring its equipment is as efficient as possible, cutting energy use in its own offices, and reducing fuel use from its vehicles.

One of Skanska’s project managers, Tore-André Thorsen, points out that decisions during the construction process can have significant impacts on reducing the emissions associated with a particular building. “By recycling the waste materials left after we have finished building, we can save 20,000 to 30,000 litres of diesel during the winter season,” Thorsen says.

Recognizing that some 84 per cent of the emissions from buildings are accounted for by the way they are used over their lifetime, Skanska sees an important business opportunity

in making the design of its buildings as energy efficient as possible. It is part of the long-term Zero Emissions Building Project, and its guidelines on managing buildings efficiently have recently been adopted by UNEP’s Sustainable Building and Construction Initiative (SBCI).

The SBCI is a partnership between the private sector, govern- ment, non-government and research organizations formed to promote the global implementation of solutions to reduce the substantial climate footprint of the world’s buildings. Among its priorities are establishing a global benchmarking system to define what sustainable buildings are, and assisting governments to develop policies to support them.

The need for a total refit of the United Nations headquarters in New York has given the UN a chance to practise what it preaches. In fact, this iconic 1950s symbol of post-war modernism was ahead of its time in terms of sustainability as well as aesthetic design: for example, large open spaces in the complex were reserved for the garden, radiant heat panels were embedded in the tower walls and the lobby floor, and East River salt water naturally cooled the chiller plant equipment.

Now, however, the building is ageing, and a major 5-year renovation project, known as the Capital Master Plan, is currently under way. Built into the plan are a number of key measures to reduce the climate footprint of the UN buildings, including: • A new double-glazed curtain wall to replace the glass en- velope of the tower, which while revolutionary at the time of its construction, bleeds energy throughout the year. • New automated interior shades and blinds to maximize natural light, heat and cooling. • New insulation for roofs and exterior walls. • A new heating, ventilation and air conditioning system using state-of-the-art control systems to save energy. • Improved lighting systems that automatically switch off when rooms are unoccupied.

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