Individual carbon and environmental footprints

This chapter addresses the management of carbon emissions and environmental impacts in urban residential settings. It refers to planetary boundaries or thresholds that, if exceeded, could potentially result in catastrophic environmental change (Rockstrom et al. 2009). Boundaries include climate change, biodiversity integrity, biogeochemical flows, ocean acidification, earth surface change, freshwater, ozone depletion, atmospheric aerosols, and chemical pollution (Steffen 2015). One way to evaluate human impacts on Earth systems within the framework of these boundaries is through calculation of an environmental footprint, a metric designed to estimate the total impact of human activities on such systems as the nitrogen cycle, carbon cycle, biodiversity, and more. As atmospheric carbon is the most significant contributor to climate change, this chapter focuses on the carbon footprint with emphasis on urban sources. Currently more than half the world's population live in urban centers, with the USA approximately 83% urban (UN 2018; World Bank 2020). An estimated 60-80% of total energy use is within urban areas and more than 70%of global greenhouse gas emissions are attributed to cities. While acknowledging the role of national and international bodies in reducing environmental impacts, this chapter emphasizes environmental and carbon footprints at the local and household scales. It concludes with the example of two community-based pilot projects in California that aim to reduce carbon and broader environmental footprints through an ambitious retrofit of existing structures. These examples highlight ensuring access to clean, reliable, and affordable energy and reduction of the environmental footprint in mixed or lower-income communities with limited financial resources through innovative, collective action at the local level.