  Effective climate mitigation strategies in cities rely on understanding and
mapping urban carbon footprints. One significant source of carbon is a product
of lifestyle choices and travel behaviors of urban residents. Although previous
research addressed consumption- and home-related footprints, activity-based
footprints of urban dwellers have garnered less attention. This study relies on
deidentified human trajectory data from 5 million devices to examine the
activity-based carbon footprint in Harris County, Texas. Our analysis of the
heterogeneity of footprints based on places visited and distance traveled
reveals significant inequality: 10% of users account for 88% of
visitation-based footprints and 71% of distance-traveled footprints. We also
identify the influence of income on activity-based carbon footprint gap of
users related to their travel behavior and lifestyle choices, with high-income
users having larger footprints due to lifestyle choices, while low- to
medium-income users' footprints are due to limited access. Our findings
underscore the need for urban design adjustments to reduce carbon-intensive
behaviors and to improve facility distribution. Our conclusions highlight the
importance of addressing urban design parameters that shape carbon-intensive
lifestyle choices and facility distribution, decisions which have implications
for developing interventions to reduce carbon footprints caused by human
activities.
