better understand long-term implications of human effects on ecosystems and health, it will need to develop scientific processes that take the long view—that is, processes that can assess changes, even minor ones, over the long term. To detect trends in environmental and human health conditions and to know whether they fall within the range of recent natural variation, long-term data on the basic functioning of environmental systems and human well-being are needed. For example, the scientific community is aware of recent changes in weather patterns, especially increases in extreme events, only because long-term weather records are available.
A concise set of environmental indicators can provide information about the status of and trends in key components of natural and human systems and provide evidence of changes that should be monitored. A modest number of environmental indicators of fundamental ecologic processes and attributes are in use (Orians and Policansky 2009; see Box 4-1 for a list of principles to guide the development of indicators). In 2002, a committee of EPA’s SAB developed a framework for assessing ecologic conditions (EPA SAB 2002) that is similar to frameworks developed by the H. John Heinz Center (Heinz Center 2002, 2008) and a National Research Council (NRC) committee (NRC 2000). The framework organizes a large number of potential indicators into six categories that represent the key attributes of an ecologic system as a whole. Each attribute can be represented by an individual indicator or by an index created by combining indicators. The six categories can also be used as a checklist for designing environmental management and assessment programs and as a guide for aggregating and organizing information. In its 2008 Report on the Environment, EPA analyzed 85 indicators related to environmental and human health that focused on air, water, land, human exposure and health, and ecologic conditions (EPA 2008). However, it has not been clear that the agency is committed to or has a plan to sustain this effort over the longer term. Furthermore, the NRC Committee on Incorporating Sustainability in the US Environmental Protection Agency (NRC 2011a) found that most indicators chosen by EPA are inadequate for exploring the relationship between economic conditions and ecosystem pressure and did not measure such important elements as environmental justice. The committee called for the development of additional sustainability indicators that could include social and economic conditions and, given the challenges of predicting long-term data, stated that any uncertainties in the understanding of indicators should be clearly communicated.
According to some analyses, it is important that EPA continue to develop and adapt a few indicators that are capable of detecting long-term changes in environmental conditions and human well-being above the inevitable noise of variability (GAO 2004). Such indicators should be designed to provide information on basic processes that are most likely to be useful in dealing with both current and future challenges, many of which are unknown today. Indicators whose