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Urban
Sustainability

How cities balance economic growth, environmental health, and social equity to create livable, resilient communities for the future.

AP Human Geography

What Is Urban Sustainability?

Urban sustainability is the practice of designing, developing, and managing cities so they meet current needs without compromising the ability of future generations to meet their own needs. This concept was popularized by the Brundtland Commission in 1987.

The Three Pillars of Sustainability

Environmental
Reducing pollution, conserving resources, protecting ecosystems, and lowering carbon emissions within and around cities.
Economic
Fostering growth, job creation, and innovation while ensuring long-term fiscal responsibility and resource efficiency.
Social
Providing equitable access to housing, healthcare, education, and public spaces for all residents regardless of income.

Why Urban Sustainability Matters

0% 30% 60% 90% 1950 1980 2010 2040 2060 ~68% urban (2050) 50% 2007 Year % Urban

The SDG 11 Framework

The United Nations Sustainable Development Goal 11 aims to "make cities and human settlements inclusive, safe, resilient, and sustainable." It provides the global framework cities use to measure and guide sustainability efforts.

SDG 11 Sustainable Cities Housing Transport Green Spaces Waste Air Quality

Key Sustainability Strategies

1
Smart Growth: Compact, walkable development that limits suburban sprawl and preserves farmland and open space.
2
New Urbanism: Mixed-use neighborhoods with diverse housing types, pedestrian-friendly streets, and accessible public transit.
3
Green Infrastructure: Rain gardens, green roofs, urban forests, and permeable surfaces that manage stormwater and cool cities.
4
Transit-Oriented Development (TOD): Concentrating housing and commercial activity around public transit stations to reduce car dependency.

Smart Growth vs. Urban Sprawl

Smart Growth Urban Sprawl
Land Use Compact, mixed-use Low-density, single-use
Transportation Public transit, walkable Car-dependent
Environmental Impact Lower emissions Higher emissions
Infrastructure Cost Shared, efficient Expensive, duplicated
Social Equity Diverse housing options Income segregation

How to Evaluate Urban Sustainability

1
Identify the policy or initiative being analyzed: transportation, housing, energy, waste, or green space.
2
Apply the three-pillar test: Does it address environmental, economic, and social dimensions?
3
Assess scale and stakeholders: Who benefits? Who is burdened? Is the impact local or regional?
4
Consider long-term viability: Does the solution create lasting change or just a short-term fix?
5
Compare to alternative models: How does it rank against other cities' approaches to the same challenge?

Example: Curitiba, Brazil

Bus Rapid Transit (BRT) Corridor Mixed-Use Zone Mixed-Use Zone Mixed-Use Zone Mixed-Use Zone Green Park Green Park Transit-Oriented Development Model

Example: Copenhagen, Denmark

Cycling Culture
Over 62% of residents commute by bicycle. The city has hundreds of kilometers of dedicated bike lanes, reducing emissions and improving public health.
Carbon Neutral Goal
Copenhagen has a goal to become the world's first carbon-neutral capital (originally targeting 2025), using wind energy, district heating, and green building standards.

The Equity Challenge

Urban sustainability must address environmental justice: the unequal distribution of environmental hazards. Low-income communities and communities of color often bear the greatest burden of pollution, heat islands, and lack of green space.

Underserved Neighborhood Factory Highway No parks, high pollution Affluent Neighborhood City Park Parks, low pollution, trees

Ecological Footprint & Urban Metabolism

An ecological footprint measures the total land and water area a city requires to produce what it consumes and absorb its waste. Urban metabolism analyzes the flows of energy, water, materials, and waste through a city: treating the city as a living system.

CITY Urban Metabolism Energy Water Food Materials Emissions Sewage Solid Waste Heat INPUTS OUTPUTS

Brownfields & Greenbelts

Brownfield Sites
Abandoned or underused industrial land, often contaminated. Redeveloping brownfields revitalizes neighborhoods and reduces the pressure to build on undeveloped land (greenfield sites).
Greenbelts
Protected zones of open land surrounding cities that prevent sprawl, protect farmland, and preserve natural habitats. London's greenbelt has been in place since 1947.

The Urban Heat Island Effect

Rural Suburban Urban Core Suburban Rural Peak Heat Cooler Temperature

Common Mistakes on the AP Exam

✕ Confusing Sprawl with Growth
Urban sprawl is not the same as urban growth. Growth can be sustainable (compact, planned); sprawl is unplanned, low-density expansion.
✕ Ignoring the Social Pillar
Students focus only on environment. Sustainability requires equity: who benefits and who is burdened by urban policies.
✕ Treating All Cities the Same
Sustainability strategies vary by context. What works in Copenhagen may not work in Lagos. Always consider development level, climate, and culture.

Key Concepts Summary

Concept Definition Example
Smart Growth Compact, walkable development Portland, OR
New Urbanism Mixed-use, pedestrian-friendly design Seaside, FL
TOD Development around transit hubs Curitiba, Brazil
Greenbelt Protected open land around city London, UK
Brownfield Redeveloped contaminated sites Pittsburgh, PA
Heat Island Urban cores warmer than surroundings Phoenix, AZ

Question 1 of 5

Which of the following best describes the concept of urban sustainability?

Question 2 of 5

Curitiba, Brazil, is widely recognized as a model of urban sustainability primarily because of its innovation in:

Question 3 of 5

A city decides to redevelop an abandoned factory site into affordable housing and a community garden. This is an example of:

Question 4 of 5

The urban heat island effect is primarily caused by:

Question 5 of 5

Which concept best explains why a sustainability plan that benefits wealthy neighborhoods but ignores low-income communities is considered incomplete?