Created at the 21st Conference of Parties in 2015 to address record buildings-related CO2 emissions worldwide, the Global Alliance for Buildings and Construction (GlobalABC) is composed of more than 150 national and local governments, businesses, inter-governmental organizations, and think tanks. These partners work together to advocate for and develop initiatives designed to achieve a zero-emission buildings and construction sector.
In its GlobalABC Roadmap for Buildings and Construction 2020-2050 report, the collaborative network lays out a range of policy, technology, and finance actions that can be taken in eight key areas to achieve net-zero CO2 emissions. The following is a look at some of these suggestions in four of the eight areas.
1. Urban Planning
The way buildings are governed is dictated by urban planning policies. Thus, these policies need to not only consider but prioritize sustainability in alignment with the United Nations’ Sustainable Development Goal 11.
“Urban form is an important determinant of urban energy demand, which encompasses the overall physical characteristics of the built environment, such as shape, size, density and configuration; the street network; and public spaces,” according to the 110-page report. “Likewise, at the building scale, compactness, height, orientation and mutual shading have a great influence on energy demand in buildings and local renewable energy potential.”
More specifically, GlobalABC recommends policymakers adhere to integrated systemic urban planning policies with cohesion between local and national governments. There should also be an emphasis on cities experiencing relatively rapid population growth. Urban planning should also consider green space, transit-oriented design, and location efficiency in addition to the establishment of net-zero carbon building codes.
GlobalABC notes that only some cities have urban heat island (UHI) mitigation strategies. The organization’s goal is to ensure all cities have UHI strategies, with UHI increment lowered by 75 percent in most urban areas by 2050. This can be achieved by reducing the number of impermeable surface areas, expanding wetlands, and increasing the installation of cool or green roofs.
2. New Buildings
Regarding the construction of new buildings, GlobalABC recommends the following vital actions: developing a roadmap strategy, implementing mandatory building codes, strengthening existing building codes, and prioritizing passive design to lessen energy expenditure from cooling systems. By 2050, the alliance hopes that all countries and jurisdictions will have implemented near-zero carbon emissions building codes, with most new buildings in compliance with strengthened codes.
GlobalABC also anticipates mandatory labeling for buildings and increased use of comprehensive passports for newly constructed buildings. These passports will comprise relevant information about specific buildings, including the types of materials used in construction, renovations, and energy use. Labeling, meanwhile, should include performance parameters such as the reflectance of surface finishes and the thermal transmittance of building materials.
Ideally, prioritized technologies in new building design and construction will include triple-glazed thermal and low-SHGC windows, light-colored or reflective surfaces, and external shading. In addition to environmental benefits, sustainable new buildings place less strain on energy systems, reduce building operation costs, and support inhabitants’ physical and mental well-being.
3. Existing Buildings
Sustainability should also be addressed in existing buildings. According to GlobalABC, this can be achieved via an increase in annual renovation rates to exceed 4 percent by 2050 and further commitment to deep energy renovations. Specifically, countries with developed economies should strive to implement renovations that reduce existing buildings’ energy consumption by 50 percent.
One key policy-related action governments can take is to create more incentives for buildings to be retrofitted to maximize their energy performance. This can be supported by financial vehicles including grants and rebates, green bonds, dedicated credit lines, energy performance/energy service contracts, and preferential tax actions on sustainable products and services. Building refurbishments, meanwhile, should involve the installation of energy-efficient windows, insulation, and external shading. Architects, engineers, and other building professionals should also be better trained in cost-effective retrofits.
Steel and cement are among the building components that generate a relatively high level of CO2 emissions through extraction, manufacturing, and construction. In fact, these processes represent roughly 4 percent and 7 percent, respectively, of global emissions. While it is much harder to decarbonize the production of steel and cement compared to other aspects of building construction, there are still actions that can be taken to achieve net-zero embodied carbon for most new buildings by 2050. However, all stakeholders on the value chain must make this a priority.
One effective global strategy would involve the establishment of targets for material energy as well as the promotion of low-carbon building materials such as clinker substitutes for cement and timber for steel. However, increased use of timber must be balanced by sustainable harvesting to reduce potential challenges associated with an increase in demand for wood. The use of these materials should also be incentivized. By 2050, GlobalABC anticipates universal adoption of material-efficient designs and low-carbon material alternatives in addition to the use of 3D printing, building information modeling, and prefabrication.