Top Papers in Environmental Policy, Second Runner-Up: Buildings as emissions culprits gases, such as the cement and steel industries, ultimately end up in buildings, says Horvath. “If we... care about global warming, we want to start with industries that actually contribute to it sigJOZSEF RONCSAK
“Assessing the End-of-Life Impacts of Buildings” by Pedro Santos Vieira and Arpad Horvath, University of California Berkeley, 2008, 42 (13), 4663-4669; DOI 10.1021/es071345l. When Pedro Santos Vieira and Arpad Horvath began looking into the sustainability of buildings, they discovered a problem. Despite the growing public interest in eco-friendly buildings, they believed that existing standards for certifying green buildings fell short of ensuring true environmental sustainability. Even the Leadership in Energy and Environmental Design (LEED) certification, issued by the U.S. Green Building Council, was not the “ultimate solution,” says Horvath, “because it comes short of really looking at the entire life cycle of buildings.” To ensure a more comprehensive approach, the duo began at the end: they examined the repercussions of building demolition. Accounting for a building’s endof-life effects can reduce the environmental footprint of new structures by increasing the recycling of materials from demolished buildings, the authors found. Their results generated one of ES&T’s best papers of 2008. Buildings have an enormous impact on the environment. Adding up their energy and water use reveals that on an annual basis, buildings consume 30-40% of the global energy supply and 16% of the world’s water supply. In North America, buildings consume more than half of the energy produced, notes Vieira. The products of some of the top industrial emitters of greenhouse
Authors Pedro Santos Vieira (left), formerly a Ph.D. student, and Arpad Horvath, professor of environmental engineering at the University of California Berkeley.
nificantly, and so we end up with buildings very quickly as the culprit.” Despite the growing demand for green buildings, designers and engineers have failed to look closely at the entire life cycles of buildings, notes Horvath. Consequently, significant levels of greenhouse gases and other toxic emissions associated with buildings’ demolition and maintenance-washing, painting, recarpeting, and so on-go unaccounted for. Similarly, people think of buildings as though they are the same,
2202 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / April 1, 2009
whether they are in Alaska or Florida, Horvath says, “and of course they are not! The materials that go into them, the construction technology, and even the designs are very different.” For example, replacing the carpets in a building in Florida is likely to emit lower amounts of greenhouse gases than doing so in an Alaskan building, because of Florida’s proximity to carpet manufacturers. To begin at the end, Vieira and Horvath developed a hybrid lifecycle assessment (LCA) model that allowed them to bypass the obvious difficulties of predicting the costs of future demolition by crediting new buildings for using recycled materials. Just increasing the recycling of concrete from present-day levels of 27-50% can reduce annual CO2 emissions by 2.7-5.6 million metric tons, the authors found. The study was part of a longer-term effort by Vieira and Horvath to build a model called BuiLCA, for conducting LCAs for buildings. “Green building technology has made tremendous advances over the past decade,” says Paul Anastas, a member of ES&T’s editorial advisory board. “This paper points out why we need to have a broad systems perspective when drawing conclusions about the benefits of some designs over some others.” Without such a broad perspective, we run the risk of “not understanding the unintended consequences,” Anastas adds. —RHITU CHATTERJEE
10.1021/es900353r
2009 American Chemical Society
Published on Web 02/18/2009
