The way we design, build, renovate and operate buildings has a big effect on our planet. Buildings account for more than one third of total energy use and its associated greenhouse gas (GHG) emissions, both in developed and developing countries. At the same time, the buildings and construction sector has largest potential for cutting GHG emissions responsible for global warming.
With proven and commercially available technologies, energy consumption in both new and old buildings can be cut by 30-50 per cent without significantly increasing investment costs. However, this potential is not being realized due to the fragmented nature of the sector; lax climate change policy in many countries, and a lack of awareness of baseline performance requirements.
Why do buildings emit so much greenhouse gasses? Energy is used to heat, cool, ventilate, and light buildings. 10-20 per cent of energy consumed in this sector is used to manufacture materials and to construct and demolish buildings and a large amount of energy is consumed by the appliances used in buildings.
Greenhouse gas emissions from buildings worldwide are set to increase sharply over the next two decades, mainly due to construction booms in Asia, the Middle East and Latin America.
Estimated at 8.6 billion tonnes in 2004, building-related GHG emissions could almost double by 2030 to reach 15.6 billion tonnes under the high-growth scenario, according to the Intergovernmental Panel on Climate Change (IPCC).
Construction is both a driver and a consequence of increasing wealth. This sector typically provides 5 to 10 per cent of employment at the national level and normally generates 5 to 15 per cent of the GDP.
Simple measures such as improved ventilation and insulation, increased use of natural lighting, the use of energy efficiency appliances and lighting alongside the use of solar and other natural heat sources, can save energy and costs. The average UK household could save around two tonnes of CO2 annually by making its home energy efficient.
The World Business Council for Sustainable Development’s Energy Efficiency in Buildings (EEB) project concludes that by cutting energy use in buildings by about 30 per cent, Europe’s energy consumption would fall by 11 per cent, more than half of the 20-20-20 target (20 per cent less carbon dioxide by 2020, with 20 per cent of “renewables” in the energy mix).
Local governments add to atmospheric damage when they design buildings to the cheapest and not the highest standards. Giving low or no priority to recycling and waste disposal policies adds to the environmental footprint buildings make.
The choice of materials is also important. For example, cement is a high-emission construction material that contributes about 5 per cent to global anthropogenic CO2 emissions, making it an important target for CO2 emission mitigation strategies. 80 per cent of all cement is made and used in emerging economies.
New buildings and their architects receive a lot of well-deserved attention when it comes to sustainability. Our imagination is captured when we read about climate-neutral office towers producing their own energy with wind turbines. The renovation of existing buildings, however, is more mundane and comes with a lot of compromises. But since the world’s building stock is already here and will be used for decades and even centuries to come, the sustainability potential of renovations is tremendous.
For example, when the UN Headquarters building in New York was designed and built almost 60 years ago, it set standards for modern architecture. Today, the ongoing renovation of the headquarters seeks to position the complex as a globally acclaimed model of efficient use of energy and resources.
Also in New York, one of the world’s leading construction companies Skanska has recently embarked on an ambitious project to renovate its USA office located on the 32nd floor of the Empire State Building, one of the city’s most historic and iconic structures. Designed and built to exceptionally high sustainability standards, the completely renovated floor offers day-lighting throughout and exceptional views for all of its employees. The office will applying for a LEED-CI Platinum certification, the highest level awarded by the United States Green Building Council. The project is part of Skanska’s commitment to be a leading green company.
Other examples of ‘green’ buildings include the Eastgate Centre in Harare, Zimbabwe, which saves 90 per cent of the energy compared with a comparable building thanks to the clever use of biomimicry principles. The mid-rise building has no conventional air-conditioning or heating, yet stays regulated year round with dramatically less energy consumption using design methods inspired by the self-cooling mounds of African termites.
UNEP’s involvement
The UNEP Sustainable Building and Construction Initiative (SBCI) is a partnership between the private sector, government, non-government and research organizations formed to promote the global implementation of these solutions through sustainable building and construction. SBCI currently has four focus areas:
- Establishing a global benchmarking system for sustainable buildings;
- Assisting governments to develop policy tools and packages supporting sustainable building and construction
- Providing input to the Kyoto Protocol on better supporting energy efficiency projects in the building sector, including through CDM projects.
- Developing and promoting the benefits of Sustainable Building Approaches in Developing Countries.