Buildings account for 32 percent of all energy use and 19 percent of energy-related greenhouse gases, according to Project Drawdown, a number that will increase as the global population urbanizes. Heating and cooling requires energy pulled from either natural gas lines or the electric grid, and buildings of all ages are subject to energy loss through gaps in the building envelope or during operations, such as occupants leaving on lights or electronics.
District energy systems (DES) for heating and cooling, particularly in dense urban areas, are a key vehicle for increasing sustainability. Although some forms of DES have existed for over a century, worldwide use is growing, and the technologies they employ are evolving. Project Drawdown ranks district heating, a form of DES, as number 27 in its 100 solutions to global warming. While district energy systems are being used throughout the United States, there is much room for growth and more needs to be done to promote their advantages.
Green roofs - and other green building components such as green walls - provide a host of benefits: aesthetic improvement, stormwater management, heat island reduction, increased biodiversity, and building cooling. Though not yet ubiquitous, a city building with a landscaped, accessible roof is now considered a desirable amenity that promotes a healthy workplace and provides cost-effective cooling benefits.
Project Drawdown ranks green roofs and cool roofs as #73 in their list of solutions to global warming, with an anticipated 0.77 gigaton reduction in carbon dioxide and $988.46 billion in operational costs by 2050. The Project Drawdown impact statement is as follows:
The building community can help combat global warming by using materials more efficiently and reducing waste. The extraction, production, and transportation of the materials necessary for building construction are significant contributors to greenhouse gas emissions, particularly due to the amount of energy they use. Project Drawdown ranks industrial recycling, including the recycling of construction waste, as number 56 of its 100 solutions to global warming.
Urban planning that mitigates water loss can reduce greenhouse gas (GHG) emissions. Though water infrastructure is a vital part of the urban landscape, urban planning often overlooks the environmental impacts of storing and transporting water and the amount of energy used during the process.
Project Drawdown highlights the significant amount of energy used to pump water from sources to treatment plants and then on to storage and distribution. Each year, over 8.6 trillion gallons of water are lost worldwide through leaks in water distribution systems, a number divided equally between low and high-income countries.