INDICATORS OF SUSTAINABILITY
Sustainability indicators and performance metrics were specifically addressed in the day two panel discussion but were also raised by other presenters and participants. As metropolitan Atlanta attempts to put sustainability principles into practice, stakeholders are interested in measuring their progress. Participants described existing metrics, particularly to measure reductions in CO2 emissions, but several participants also described other types of metrics (e.g., related to community health or mobility). Many participants also noted that these metrics could become important in the context of competitiveness among metropolitan regions if citizens begin to demand more action on sustainability.
REDUCING THE REGION’S CARBON FOOTPRINT
Marilyn Brown, professor, School of Public Policy, Georgia Tech, examined sustainability through the lens of energy consumption and greenhouse gas emissions. She began with a forecast of the growth of CO2 emissions in the United States and noted that a national goal ought to be not only to stop cumulative growth in emissions, but to make these growth rates negative. To do so, the United States needs to have a cumulative emissions budget. As Dr. Brown pointed out, however, implementation will fall primarily to cities and local governments, and thus it is important to understand emissions at the metropolitan level.
Dr. Brown cited a 2005 study by The Brookings Institution (Brown et al., 2008) of carbon footprints of the 100 largest metropolitan areas, which found that people living in dense urban areas generate significantly lower emissions. She explained that U.S. cities offer great opportunities for improvements in energy efficiency and conservation because of the high concentration of buildings and the compact
infrastructure (see Figure 4–1). Although they contain 65 percent of the population and create 76 percent of gross domestic product, they only produce 56 percent of carbon emissions. Dr. Brown noted that obtaining energy data at a county or zip code level is difficult. Some data are proprietary and can only be estimated.
SUSTAINABILITY AS A POINT OF DIFFERENTIATION
K.C. Boyce, Deputy Executive Director, Membership and Regional Impact, ICLEI-Local Governments for Sustainability, discussed how progress toward sustainability might be measured in the region. He presented the STAR Community Index, which uses comparative analysis to provide a common way of measuring progress in sustainability—
economic, environment, and equity indices. The index has 81 metrics categorized under 10 goal areas; each has its own structure, consisting of a goal, purpose, and measure. He emphasized that the STAR Community Index has a “high bar, but a low floor” so that top-performing communities would have incentive to continue making progress, but lower-performing communities would not be precluded from measuring their progress. Mr. Boyce also remarked that communities were expressing interest in understanding the range of positive possibilities for becoming more sustainable (rather than only measuring the decrease in undesirable indicators).
Mr. Boyce noted that, until recently, indicators of sustainability for different cities did not have enough in common to make useful quantitative comparison. This makes it difficult if not impossible to verify claims emanating from communities. To share a common vision and carry out concerted action, it is useful to have a common language and set of metrics. He acknowledged that this is not without challenges, and he cited the example of defining “adequate” health care. At the same time, Mr. Boyce noted that not all sustainability indicators are directly comparable between communities.
Carol Couch, Senior Public Service Associate, College of Environment and Design, University of Georgia, elaborated on this when she pointed out that stakeholders needed to have a benchmark for the region’s ecosystem services. Quantifying (and, where possible, monetizing) these services would help improve decision makers’ understanding of the tradeoffs inherent in different patterns of development. Graeme Lockaby, director, Center for Forest Sustainability, Auburn University, pointed out that macroeconomic analyses are not suited to local ecological scales, and so it is easy to miss declines in ecosystem services resulting from urban expansion. He cited two specific examples from his studies in western Georgia—first, that regional water availability tends to decrease as urbanization (i.e., land conversion) increases, and second, that the threshold for urban forest canopy and species diversity is about 15 percent. In these cases, changes to the land threaten services that at least some residents in the region value.
Environmental justice, a priority issue in metropolitan Atlanta and at a federal level, is another spatial indicator. Several participants noted that, in addition to concerns about environmental pollution’s adverse impacts on segments of the regional population (e.g., by race or income),
it will also be important to measure the degree to which all segments of the population are benefiting from environmental improvements in the region. Examples included access to green space, healthy food options, and multiple modes of transit.
PUBLIC HEALTH INDICATORS
Christopher Portier, Director of the National Center for Environmental Health, U.S. Centers for Disease Control and Prevention (CDC), suggested that health indicators, such as gains in life expectancy from pollution reductions, offered a positive way to communicate the impact of sustainability efforts. In the same way that efficiency improvements are communicated in terms of consumer savings over time, improvements in the built environment that also improve health outcomes can be monetized (e.g., reduced medical expenditures) and provide a direct connection to citizens. Dr. Portier concluded that the way we design our communities and use our land will either promote or harm human health. Therefore, the CDC is becoming more involved in building capacity to support Health Impact Assessments for land-use and transportation projects.
Jeremy Hess, assistant professor, Department of Environmental Health, Rollins School of Public Health, Emory University, posed a question to the group about which health indicators could be used as a measure of urban sustainability. As many participants noted, health problems such as asthma and obesity are significant concerns in metropolitan Atlanta, and so linking these concerns to their environmental stressors could help make sustainability a more tangible idea for residents in the region. Dr. Hess added survival from common cancers to this list. These indicators are highly correlated with poverty and restricted access to health care. Incidence of obesity and diabetes are linked to limited mobility, limited access to nutritious food, and poor education. Dr. Hess reiterated that shifting our attention and investment to creating livable and sustainable communities can have a positive impact on public health.