Chapter 12 : Built Environment, Urban Systems, and Cities. Fifth National Climate Assessment
| Authors: | Jayajit Chakraborty, So-Min Cheong, Christopher Clavin, Makena Coffman, David M. Hondula, David Hsu, Viniece L Jennings, Jesse M Keenan, Ann Kosmal, Tischa A. A. Munoz, Na’Taki Osborne Jelks |
| Year: | 2024 |
| Type: | Book Chapter |
| Station: | International Institute of Tropical Forestry |
| Source: | Fifth National Climate Assessment |
Abstract
The built environment includes human-made or modified landscapes, structures, and infrastructure systems that bring together people, services, and economic activities. This chapter focuses on the built environment found in and around cities and suburbs across the country, where most Americans live and work. Cities and urban areas are also a key part of the country’s culture, nature, and historical heritage. The choices that we make today in cities, suburbs, and the built environment to address climate change will affect the livelihoods, well-being, and quality of life for all Americans in the future.
Climate change has multiple and compounding effects on cities and the built environment. Cities and urban areas are notable drivers of climate change through the creation of greenhouse gas (GHG) emissions from human consumption and land-use change (KM 12.1). Attributes of the built environment also influence local and regional climates, which are further impacted by climate change. Across the country, cities face rising temperatures and sea levels, as well as changes in extreme events such as droughts, wildfires, extreme precipitation, flooding, and heatwaves (KM 12.2). Climate change is projected to have cascading effects on critical energy, transportation, communication, and supply chain systems (Chs. 5, 13, 18; Focus on Risks to Supply Chains). Climate projections also show demographic and land-use changes and uneven distribution of climate change risk (Chs. 2, 3). Urban infrastructure will be further strained by climate change unless effective GHG mitigation and climate adaptation actions are undertaken.
Many city governments are planning for short- and medium-term climate risks to protect their economies and the well-being of communities and residents (KM 12.3). These plans involve forward-looking infrastructure designs, land use and zoning, building codes, decision support tools, and services to ensure residents’ quality of life. However, implementation of these actions is uneven and limited in scale and often lacks long-term vision (Chs. 31, 32), and not all city governments recognize the inequities experienced by overburdened communities. Persistent gaps in the provision of health services, housing, food, transportation, employment opportunities, and green spaces put already-overburdened communities at a greater risk of adverse climate impacts.
The recent growth in the number of local and community-led approaches points toward the potential for more inclusive planning and implementation of climate actions (KM 12.4). Still, without evidence-based strategies to evaluate climate actions, cities risk investing in infrastructures and built environment systems that lock in future urban GHG emissions, underperform or have shortened life spans, and exacerbate adverse climate risks to overburdened communities.