Mitigating Urban Greenhouse Gas Emissions: Decarbonization Frameworks for Portland and Delhi

Climate change poses one of the most serious challenges to our planet, with urban areas contributing significantly to the greenhouse gas (GHG) emissions that drive this crisis. Although cities occupy only about 2% of the Earth’s land, they are responsible for over 70% of global GHG emissions and account for two-thirds of worldwide energy consumption. By 2050, an estimated two-thirds of the global population will live in cities. Therefore, reducing emissions within urban landscapes is essential to combine climate change. The United States and India rank among the top global emitters of carbon, so reducing emissions in these nations is essential to achieving international climate targets. Currently, 82% of Americans and 35% of Indians reside in urban areas. With India’s rate of urbanization accelerating, projections indicate that by 2050, 60% of the country’s population will be living in cities. Delhi, the focal city in this study, is expected to become the world’s largest city by 2028. Such urban expansion will demand considerable infrastructure investment, and prioritizing sustainable, climate-conscious development will be vital to achieving lasting GHG reductions. While urbanization in the United States may be slower than in India, American cities like Portland (the second city analyzed in this study) still make a substantial contribution to both national and global GHG emissions, with per capita emissions significantly higher than those of India and other rapidly developing nations. This study outlines various deep decarbonization strategies for Delhi and Portland, examining specific technology and policy measures. To approach urban decarbonization, it is helpful to consider seven key infrastructure sectors: food, water, buildings, energy, transportation and connectivity, waste and sanitation, and public spaces. These combined sectors represent 88% of global GHG emissions. Following this framework, the study begins with an analysis of each city’s current carbon footprint, an essential step in crafting effective decarbonization strategies. Using a community infrastructure footprint (CIF) method, which employs a life cycle assessment (LCA) across these seven sectors, this approach includes emissions beyond city boundaries for a comprehensive emissions overview.