Energy use in buildings accounts for one-third of greenhouse gas emissions, but the huge potential of the construction sector to combat climate change has not been realized, according to the United Nations Environment Programme (UNEP).

The UN Intergovernmental Panel on Climate Change (IPCC), co-recipient of last year''s Nobel Peace Prize, has warned that building-related emissions could nearly double from almost 9 billion tons in 2004 to nearly 16 billion in 2030.

The surge will be driven in large part by construction booms in the next two decades in Asia, the Middle East and Latin America.

“Report after report is now underlining the huge, cost-effective savings possible from addressing emissions from existing buildings alongside designing new ones that include passive and active solar up to low-energy heating and cooling systems and energy-efficient systems,” said UNEP Executive Director Achim Steiner.

A new study notes that today''s commercially available technologies allow for energy consumption to be halved in both new and old buildings relatively cheaply through measures such as improved ventilation and insulation, stepped up use of natural lighting and the use of solar and other natural heat sources.

A report entitled “The Kyoto Protocol, the Clean Development Mechanism, and the Building and Construction Sector” cites high administrative costs and weak financial incentives as being among the barriers for approval by the CDM.

For example, eight projects proposed by a Brazilian supermarket chain were rejected because of difficulties in accounting for the projected 20,000 tons of annual carbon savings. Only $3,000 of carbon revenue would be generated by the store, which is less than the basic operating costs for the projects and would not cover the energy-efficient equipment necessary.

That initiative brings together countries, cities, businesses and organizations which pledge to significantly reduce greenhouse gas emissions.

“For many small island developing States like Niue climate neutrality is more than just a concept – it is a matter of survival,” Mr. Steiner said today of the nation, with a population of some 1,700, releases approximately 0.003 million metric tons of carbon dioxide annually.

Slough, home to nearly 120,000 people and situated between London and Bath, is seeking to have all public transport and council vehicle run on cleaner fuel and slash its emissions by one-fifth in the coming two decades.

Waitakere, the fifth largest city in New Zealand, is aiming to stabilize per capita emissions by 2010 and reduce them 80 per cent by 2051.