G Gray Consumption Gary Haq Stockholm Environment Institute, Department of Environment and Geography, University of York, Heslington, UK Synonyms Carbon footprint; Energy use, greenhouse gas emissions; Population aging Definition Gray consumption can be defined as the use of goods and services (e.g., housing, food, heating, and personal travel) by older people, which meet basic needs and improve quality of life. These activities require energy and produce greenhouse gas (GHG) emissions. An individual’ s pattern of consumption changes over the life course, reflecting wealth, age, health, and social needs. Older people’ s consumption habits therefore con- tribute to rising GHG emissions and climate change (Estiri and Zagheni 2019; Menz and Welsch 2012). Overview Demographic changes such as aging, urbanization, population growth, and household size have impli- cations for consumption patterns and GHG emis- sions that drive climate change (O 0 Neill et al. 2012). There is increasing evidence to suggest that GHG emissions raise as a population grows older (Zagheni 2011; Menz and Welsch 2012). The effects of a changing climate are already impacting natural and human systems with ice caps melting, sea level rise, and more extreme weather events. The global mean temperature is likely to reach 1.5  C above pre-industrial levels between 2030 and 2052 if it continues to increase at the current rate. Rapid far-reaching and unprecedented changes in all aspects of society are therefore needed to keep below 1.5  C heating. This will require changes to the lifestyles, consumption pref- erences, and consumer behavior of older people (IPCC 2018; UN Environment 2019). Key Research Findings Population aging and changing consumption pat- terns are increasing GHG emissions in both devel- oped and developing nations. For example, in China, small and aging households are expected © Springer Nature Switzerland AG 2019 D. Gu, M. E. Dupre (eds.), Encyclopedia of Gerontology and Population Aging, https://doi.org/10.1007/978-3-319-69892-2_468-1