U.S. Cities Factsheet

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Large, densely populated, and bustling with activity, cities are cultural and economic centers, providing employment, leisure, and educational opportunities. Energy and resources flow in and out to support population and infrastructure. However, there is increasing attention on the environmental impacts of cities, and the significant opportunities to reduce the impact of the built environment and improve the livelihoods of urban residents.

Urban Land Use Patterns

  • 83% of the U.S. population lives in urban areas, up from 64% in 1950. By 2050, 89% of the U.S. population and 68% of the world population is projected to live in urban areas.1
  • More than 325 urban areas in the U.S. have populations above 100,000; NYC, with 8.34 million inhabitants, is the largest.4,5
  • While the annual rate of urbanization, i.e., the changing of land from forest or agricultural uses to suburban and urban uses, has decreased (2.2% in 2020 to 1.7% in 2023), an increasing percentage of the world’s population is living in urban centers (46.7% in 2000 to 57.3% in 2023).6,7 Between 2000 and 2020, urban land area in the U.S. increased by 14%. Urban land area is 105,493 mi2, or 3% of total land area in the U.S., and is projected to more than double by 2060.8,9,10
  • Between 2010 and 2020 total housing units increased 6.7%, compared to the 13.6% increase between 2000 and 2010.11
  • The average population density of metropolitan statistical areas (MSAs) in 2010 was 283 people per mi2.8 The U.S. average in 2020 was 94 per mi2.12 In NYC, the 2020 population density was 29,303 people per mi2.5
  • The county of New York, New York has the greatest density of housing units (40,339) per mi2 of land area.9 
  • One study found that doubling population-weighted urban density reduces CO2 emissions from household travel and residential energy use by 48% and 35%, respectively.13
  • Sprawl, the spreading of a city and suburbs into surrounding rural land, increases traffic and energy use, and results in air and water pollution and flooding.14 Sprawl has also been shown to perpetuate habitat loss, automobile dependency, reductions of open space, and quality of life.15 
  • According to Smart Growth America’s Sprawl Index (based on development density, land use mix, activity centering and street accessibility), the most sprawling MSAs of the 221 surveyed are Hickory-Lenoir-Morganton, NC, Atlanta-Sandy Springs-Marietta, GA, Clarksville, TN-KY, and Prescott, AZ.16 
Population Trends of the Largest U.S. Cities, 2000-2021 2,3

 Built and Natural Environment

  • Residential (18.4 quads) and commercial (16.1 quads) sectors accounted for 37% of total energy consumption and 33.4% of energy-related emissions in 2023 (1,601 Mt of CO2).17
  • 70% of global emissions can be attributed to urban areas, driven by population size, income, and form of urbanisation.18 Of these emissions 21% come from urban transport.19
  • The “urban heat island effect,” in which average annual temperatures average 1-7°F higher in cities than surrounding suburban and rural areas, results in increased energy demand, air pollution, GHG emissions, and heat-related illness, as well as decreased water quality.20
  • Urban tree canopies decrease the urban heat island effect.21 Urban tree cover in the U.S. is 39.4% and has been declining, while impervious surfaces increased to 26.6% of urban area.10 Extensive urban reforestation would increase carbon sequestration and reduce electricity-related GHG emissions while providing over $9B worth of benefits annually.22 
  • Air Quality Index is an important environmental metric in cities. Since 2000, emissions from key pollutants have decreased and, with them, the number of unhealthy air days for urban residents. Almost 4 in every 10 Americans, 131.2M people, still live in regions containing unhealthy levels of particulate or ozone pollution.23,24
  • The concentration and toxicity of contaminants in streams increases with the degree of urban development. Pollutants are introduced from runoff, treated and untreated sewage, and industrial processes.25
  • Stormwater runoff from the built environment is a principal contributor to water quality impairment of water bodies.26
Urban Density and Transportation-Related Energy Consumption14

Transportation and Mobility (See Personal Transportation Factsheet)

  • In 2019, 56.1B passenger-mi were traveled on U.S. public transit. In 2020, this decreased 32.9B and further decreased to 23.3B in 2021 during the COVID-19 pandemic.28,29
  • Busses, bus rapid transit (BRT), trolleybusses, and heavy rail made up 86% of public transportation trips in 2021. Using public transit rather than a personal vehicle lowers carbon emissions by 55%.29,31 Public transportation in the U.S. prevents 102.2B vehicle miles, 5.3B gal of gasoline, and 37 Mt of CO2 emissions per year.32 $1B invested in public transportation yields $5 billion in GDP growth and nearly 50,000 jobs.33
  • Congestion is a serious problem in urban areas, causing an additional 8.7B hours of travel time and an extra 3.5B gal of fuel use by urban Americans in 2019.34
  • In 2019, transit buses used 89.5T Btu and traveled 19.3B PM, while rail used 47.1T Btu and traveled 39.3B PM. In comparison, passenger cars and trucks used 15,108T Btu and traveled 4,470B PM.35
  • Between 2020 and 2023, there was a 53.4% increase in ridership on all modes of public transportation; however, 2023 ridership was 28.3% lower than in 2019.36,37,38
  • In large U.S. cities, the average amount of land covered by parking lots is 26%.39
Number of Public Transportation Passenger Trips

Socioeconomic Patterns

  • The average unemployment rate of metropolitan areas in March 2024 was 3.9%, ranging from a low of 1.6% in Burlington-South Burlington, VT to a high of 16.1% in El Centro, CA.40  In 2018, U.S. metro economies accounted for 91.1% of GDP, 91.8% of wage income, and 88.1% of jobs.41
  • Only 9 countries had a higher 2018 GDP than the NYC area.41
  • The median household income inside MSAs is $73,823; outside MSAs it is $53,750.42 
  • Poverty rates are lower within metropolitan areas than outside: 11% compared to 14.1% in 2020.43 In the 50 largest U.S. cities, households in the top 5% of wealth earn 11.6 times more than those in the bottom 20%. Nationally, this disaparity is 9.3 times.44 
 
Climate Solution Policies and Activities in Cities

Solutions and Sustainable Alternatives

  • A sustainable urban area is characterized by the preservation of a quality environment, efficient use of renewable energy resources, the maintenance of a healthy population with access to health services, and the presence of economic vitality, social equity, and civic engagement.46
  • An integrated approach to environmental management, measures to counter sprawl, the establishment of linkages among community, ecology, and economy, and coordinated stakeholder interaction are necessary for achieving sustainability in cities.46,47
  • Well-being can be improved by prioritizing means to reduce climate risk for low-income and marginalized communities.18
  • 1,066 mayors have signed on to the 2005 U.S. Mayors Climate Protection Agreement, committing to reduce carbon emissions below 1990 levels, in line with the Kyoto Protocol.48
  • The EPA offers clean energy programs, information, training, grants, and resources to assist local governments.
  • ICLEI (International Council for Local Environmental Initiatives) is an international association of national, regional, and local governmental organizations that develops locally designed initiatives to achieve sustainability objectives.49
  • Smart Growth America is a coalition working to improve the planning and building of towns, cities, and metro areas.50
Cite As

Center for Sustainable Systems, University of Michigan. 2024. “U.S. Cities Factsheet.” Pub. No. CSS09-06.

  1. United Nations (UN) Population Division (2018) World Urbanization Prospects: The 2018 Revision.

https://population.un.org/wup/Download/

  1. U.S. Census Bureau (2011) “Incorporated Places with 100,000 or More Inhabitants in 2010.”

Graphic

https://www.census.gov/library/publications/2011/compendia/statab/131ed/population.html

  1. U.S. Census Bureau (2023) City and Town Population Totals 2020-2022, Incorporated Places of 50,000 or More.

https://www.census.gov/data/tables/time-series/demo/popest/2020s-total-cities-and-towns.html

  1. U.S. Census Bureau (2022) City and Town Population Totals 2020-2021, Incorporated Places of 50,000 or More.

https://www.census.gov/data/tables/time-series/demo/popest/2020s-total-cities-and-towns.html

  1. U.S. Census Bureau (2023) QuickFacts New York City, New York.

https://www.census.gov/quickfacts/newyorkcitynewyork

  1. The World Bank (2023) Urban Population Growth (Annual %).

https://data.worldbank.org/indicator/SP.URB.GROW

  1. The World Bank (2023) Urban Population (% of total population).

https://data.worldbank.org/indicator/SP.URB.TOTL.IN.ZS?end=2019&start=1960&view=chart

  1. U.S. Census Bureau (2012) United States Summary: 2010 Population and Housing Unit Counts. 2010 Census of Population and Housing.

https://www2.census.gov/library/publications/decennial/2010/cph-2/cph-2-1.pdf

  1. U.S Census Bureau (2023) County-level Urban and Rural information for the 2020 Census.

https://www.census.gov/programs-surveys/geography/guidance/geo-areas/urban-rural.html

  1. Nowak, D. and E. Greenfield (2018) Declining Urban and Community Tree Cover in the United States. Journal of Urban Forestry and Urban Greening: 32-55.

https://www.sciencedirect.com/science/article/pii/S1618866717307094

  1. U.S. Census Bureau (2023) "Housing Characteristics: 2020."

https://www2.census.gov/library/publications/decennial/2020/census-briefs/c2020br-09.pdf

  1. U.S. Census Bureau (2021) "Historical Population Density Data (1910-2020)."

https://www.census.gov/data/tables/time-series/dec/density-data-text.html

  1. Lee, S., and Lee, B. (2014) The Influence of Urban Form on GHG Emissions in the U.S. Household Sector. Journal of Energy Policy, 68: 534-549.

https://www.sciencedirect.com/science/article/pii/S0301421514000299

  1. European Environment Agency (2004) "Glossary: Urban Sprawl."

https://www.eea.europa.eu/help/glossary/eea-glossary/urban-sprawl

  1. Nature Education Knowledge (2013) "The Characteristics, Causes, and Consequsences of Sprawling Development Patterns in the United States."

https://www.useful-community-development.org/urban-sprawl-and-public-health.html

  1. Ewing, R., Shima Hamidi. (2014) Measuring Sprawl 2014. Smart Growth America.

https://smartgrowthamerica.org/wp-content/uploads/2016/08/measuring-sprawl-2014.pdf

  1. U.S. Energy Information Administration (EIA) (2024) Monthly Energy Review April 2024.

https://www.eia.gov/totalenergy/data/monthly/

  1. Intergovernmental Panel on Climate Change (IPCC) (2023) Synthesis Report of the IPCC Sixth Assessment Report (AR6) Longer Report.

https://www.ipcc.ch/report/ar6/syr/

  1. World Resources Institue (2021) Invest in Walking and Cycling for Sustainable, Safe Cities.

https://www.wri.org/insights/invest-walking-cycling-sustainable-safe-cities

  1. U.S. Environmental Protection Agency (EPA) (2020) “Learn About Heat Islands.”

https://www.epa.gov/heatislands/learn-about-heat-islands

  1. Nowak, Greenfield (2012) Tree and impervious cover in the United States. Landscape and Urban Planning: 21-30.

https://www.sciencedirect.com/science/article/pii/S0169204612001193?via%3Dihub

  1. Mcdonald, R.I., et al. (2024) Current inequality and future potential of US urban tree cover for reducing heat-related health impacts. Urban Sustainability 4: 18.

https://www.nature.com/articles/s42949-024-00150-3

  1. U.S. EPA (2021) Our Nation's Air.

https://gispub.epa.gov/air/trendsreport/2021/documentation/AirTrends_Flyer.pdf

  1. American Lung Association (2024) State of the Air.

https://www.lung.org/research/sota/key-findings

  1. USGS (2012) Effects of Urban Development on Stream Ecosystems in Nine Metropolitan Study Areas Across the United States.

https://pubs.usgs.gov/circ/1373/pdf/Circular1373.pdf

  1. National Research Council (2008) Urban Stormwater Management in the United States.

https://www3.epa.gov/npdes/pubs/nrc_stormwaterreport.pdf

  1. Adapted from UNEP (2008) “Kick the Habit: A UN Guide to Carbon Neutrality.”

https://www.unep.org/resources/report/kick-habit-un-guide-climate-neutrality 

  1. American Public Transportation Association (2022) Public Transportation Factbook.

https://www.apta.com/research-technical-resources/transit-statistics/public-transportation-fact-book/

  1. American Public Transportation Association (2023) Public Transportation Factbook.

APTA-2023-Public-Transportation-Fact-Book.pdf

  1. American Public Transportation Association (2024) Public Transportation Ridership Report, Fourth Quarter 2023.

https://www.apta.com/research-technical-resources/transit-statistics/ridership-report/

  1. Transit Cooperative Research Program (2021) An Update on Public Transportation's Impacts on Greenhouse Gas Emissions.

https://www.trb.org/Main/Blurbs/181941.aspx

  1. APTA (2008) The Broader Connection between Public Transportation, Energy Conservation and Greenhouse Gas Reduction. 

http://onlinepubs.trb.org/onlinepubs/tcrp/docs/TCRPJ-11Task3-FR.pdf

  1. APTA (2020) Economic Impact of Public Transportation Invetment.

*APTA-Economic-Impact-Public-Transit-2020.pdf

  1. Texas A&M Transportation Institute (2021) 2021 Urban Mobility Report.

https://static.tti.tamu.edu/tti.tamu.edu/documents/mobility-report-2021.pdf

  1. U.S. Department of Energy (DOE), Oak Ridge National Lab (2022) Transportation Energy Data Book: Edition 40.

https://tedb.ornl.gov/

  1. APTA (2023) Public Transportation Ridership Report, Fourth Quarter 2022.

https://www.apta.com/research-technical-resources/transit-statistics/ridership-report/

  1. APTA (2021) Public Transportation Ridership Report, Fourth Quarter 2020.

https://www.apta.com/wp-content/uploads/2020-Q4-Ridership-APTA.pdf

  1. American Public Transportation Association (2024) Public Transportation Ridership Report, Fourth Quarter 2023.

https://www.apta.com/wp-content/uploads/2024-Q1-Ridership-APTA.pdf

  1. Scientific American (2024) Parking Lots Cause more Heat and Flooding - Here's How 100 U.S. Cities Rank.

https://www.scientificamerican.com/article/parking-lots-cause-more-heat-and-flooding-heres-how-100-u-s-cities-rank/#:~:text=Impervious%20parking%20lots%20can%20worsen%20urban%20sheet%20flooding,urban%20heat%20island%20effect%20in%20many%20city%20centers.

  1. U.S. Department of Labor, Bureau of Labor Statistics (2024) Unemployment Rates for Metropolitan Areas.

https://www.bls.gov/web/metro/laummtrk.htm

  1. The United States Conference of Mayors (2019) U.S. Metro Economies - GMP and Employment 2018-2020.

https://www.usmayors.org/wp-content/uploads/2019/09/mer-2019-09.pdf

  1. U.S. Census Bureau (2022) Income in the United States 2021.

https://www.census.gov/library/publications/2022/demo/p60-276.html

  1. U.S. Census Bureau (2021) Income and Poverty in the United States: 2020.

https://www.census.gov/library/publications/2021/demo/p60-273.html

  1. Brookings Institute (2015) Some Cities are still more unequal than others-An update.

https://www.brookings.edu/articles/some-cities-are-still-more-unequal-than-others-an-update/

  1. Center for Climate and Energy Solutions (2020) Mayors Leading the Way on Climate

https://www.c2es.org/document/mayors-leading-the-way-on-climate-2020/ (need to add to excel)

  1. Budd, W., et al. (2008) "Cultural sources of variations in U.S. urban sustainability attributes." Cities, 25(5): 257-267.

http://www.sciencedirect.com/science/article/pii/S0264275108000462

  1. Hecht, A. and W. Sanders (2007) "How EPA research, policies, and programs can advance urban sustainability." Sustainability: Science, Practice, & Policy, 3(2): 37-47.

https://www.tandfonline.com/doi/abs/10.1080/15487733.2007.11908001

  1. U.S. Conference of Mayors (2020) Mayors Climate Protection Center.

https://www.usmayors.org/mayors-climate-protection-center/

  1. ICLEI Global (2021) “About Us.”

https://www.iclei.org/en/About_ICLEI_2.html

  1. Smart Growth America (2021) “About Us.”

http://www.smartgrowthamerica.org/about-us

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