Location, Location, Low-Carbon: The Surprising Climate Math of Where We Live
While urban planners have long considered the impacts of density, new research reveals additional housing and neighborhood design factors that significantly impact our carbon footprint in residential developments. In “Beyond density: Examining overlooked drivers of housing and neighborhood greenhouse gas emissions,” Aldrick Arceo (University of Toronto), Marianne Touchie (University of Toronto), and William O’Brien (Carleton University) analyzed four housing types and 529 neighborhood case studies from Toronto to identify key climate pollution drivers across diverse urban and suburban contexts.
Key Takeaways:
- Multi-unit buildings produce 45-62% less climate pollution per person than detached homes, with high-rise apartments showing pollution 32% lower than attached houses (p. 10).
- Neighborhoods with good walkability and transit access reduce climate pollution regardless of density, with “Walker’s Paradise” areas showing nearly half the pollution of car-dependent zones (p. 12).
- Larger households, neighborhoods with more rental properties, and lower household income levels correlate with lower per-capita climate pollution (p. 13).
The researchers employed life cycle assessment to track climate pollution from building materials, home operations, and transportation patterns. Their methodology integrates these elements into a single framework, providing reliable data reflecting real-world conditions.
Housing Form Impact: Detached houses use nearly three times more carbon-intensive materials per person than other housing types, with concrete, mineral insulation board, and brick being the main contributors. And their day-to-day pollution is 2.3-5.5 times higher. Most of this comes from natural gas heating. Detached homes have a greater exterior surface area compared to interior living space, creating more heat loss in winter and heat gain in summer.
Location Influence: Mobility-related pollution was 1.2-1.4 times higher for detached houses, but location proved more important than building type. Some apartment dwellers in car-dependent suburbs generate higher transportation pollution than detached-home residents near downtown. Ultimately, neighborhoods with high Walk Scores showed significantly lower overall climate pollution, regardless of housing density.
Household Factors: Neighborhoods with larger households, more renters, and diverse income levels consistently showed lower per-capita climate pollution. This occurs partly because shared living spaces naturally reduce per-person energy use – larger households divide heating and electricity across more people. Similarly, rental properties in Toronto are typically smaller than owner-occupied homes. These household composition factors explain significant variations in pollution even between areas with similar physical characteristics.
This research offers a practical path forward for California’s housing and climate goals: Attached homes and apartments produced lower climate pollution than detached houses. Walkable, transit-accessible neighborhoods consistently showed lower carbon footprints. Areas with larger households and more rental options demonstrated better per-person efficiency. Electrification presents a clear opportunity to address natural gas heating, which dominated operational emissions. These findings suggest policymakers can achieve better results by considering building types, neighborhood design, and household patterns together rather than in isolation.