Development of and improvements in metrics or indicators that span and integrate all relevant physical, chemical, biological, and socioeconomic domains are needed to help guide various actions taken to respond to climate change. Such metrics should focus on the “vitals” of the Earth system, such as freshwater and food availability, ecosystem health, and human well-being, but should also be flexible and, to the extent allowed by present understanding, attempt to identify possible indicators of tipping points or abrupt changes in both the climate system and related human and environmental systems. Many candidate metrics and indicators exist, but additional research will be needed to test, refine, and extend these measures.

One key element in this research area is the development of more refined metrics and indicators of social change. For example, gross domestic product (GDP) is a well-developed measure of economic transactions that is often interpreted as a measure of overall human well-being, but GDP was not designed for this use and may not be a good indicator of either collective or average well-being (Hecht, 2005). A variety of efforts are under way to develop alternative indicators of both human well-being and of human impact on the environment that may help monitor social and environmental change and the link between them (Frey, 2008; Hecht, 2005; Krueger, 2009; Parris and Kates, 2003; Wackernagel et al., 2002; World Bank, 2006).

A number of certification systems have emerged in recent decades to identify products or services with certain environmental or social attributes, assist in auditing compliance with environmental or resource management standards, and to inform consumers about different aspects of the products they consume (Dilling and Farhar, 2007; NRC, 2010d). In the context of climate change, certification systems and standards are sets of rules and procedures that are intended to ensure that sellers of credits are following steps that ensure that CO₂ emissions are actually being reduced (see Chapter 17). Certification systems typically span a product’s entire supply chain, from source materials or activities to end consumer. Performance standards are frequently set and monitored by third-party certifiers, and the “label” is typically the indicator of compliance with the standards of the system.

Natural resource certification schemes, many of which originated in the forestry sector, have inspired use in fisheries, tourism, some crop production, and park management (Auld et al., 2008; Conroy, 2006). Variants are also used in the health and building sectors and in even more complicated supply chains associated with other markets. Certification schemes are increasingly being used to address climate change issues,