AP Syllabus focus:
‘Climate change affects cities through increased heat, extreme weather, and risk to infrastructure, requiring mitigation and adaptation strategies.’
Climate change reshapes urban environments by intensifying heat, stressing infrastructure, and amplifying hazards. Cities must use coordinated planning, technology, and policy to manage growing risks.
Climate Change and Urban Vulnerability
Cities are uniquely exposed to climate change because of their dense populations, concentrated infrastructure, and extensive built environments. These characteristics magnify the effects of increasing temperatures, extreme weather, and environmental instability. Climate impacts often interact with existing social inequalities, meaning vulnerable populations experience greater risks and fewer resources for adaptation.
Urban Heat Intensification
One of the most direct ways cities experience climate change is through rising temperatures.
Urban Heat Island (UHI) effect increases temperatures due to dense development, limited vegetation, and heat-absorbing materials such as concrete and asphalt.
This diagram shows a cross-section of temperatures across rural, suburban, and urban areas, illustrating the urban heat island effect. The tallest, most densely built districts have the highest air temperatures, while vegetated rural areas remain coolest. The graphic includes more meteorological detail than the syllabus requires, but its basic pattern helps students visualize how urban form intensifies heat. Source.
Higher temperatures worsen heat-related illnesses, increase cooling demand, and strain energy systems.
Nighttime temperatures remain elevated, reducing opportunities for cooling and increasing public health risks.
Urban Heat Island: A temperature pattern in which urban areas experience significantly higher temperatures than surrounding rural areas due to human-built surfaces and limited vegetation.
Elevated heat also reduces air quality as pollution reacts more quickly in warm conditions, generating harmful ground-level ozone.
Extreme Weather in Urban Areas
Climate change increases the frequency and intensity of extreme weather, and densely built cities face amplified effects.
Flooding and Storm Impacts
Cities often sit in vulnerable locations such as coasts, riverbanks, and deltas. As a result, extreme precipitation events and storm surges can produce:
Urban flooding, especially where drainage infrastructure is old, undersized, or poorly maintained
Coastal flooding intensified by sea-level rise
Wind damage to buildings and utilities
Electricity and transportation disruptions that affect mobility, safety, and economic activity
In low-income neighborhoods, inadequate drainage and lower-quality housing increase exposure to storm hazards. These impacts can displace residents, damage businesses, and delay critical services.
Drought and Water Stress
Climate change also intensifies drought, which affects water supplies and increases competition over limited resources.
Cities may face water scarcity, forcing municipalities to restrict consumption.
Reduced river flow and reservoir levels challenge industrial operations and household needs.
Drought conditions elevate wildfire risk on urban fringes, threatening structures and worsening air quality.
Infrastructure at Risk
Urban infrastructure—including transportation, energy, water, and communication networks—is highly sensitive to climate hazards.
Transportation Systems
Extreme heat can warp roads, soften asphalt, and distort rail lines, slowing or halting services. Flooding disrupts highways, subway tunnels, and airports. Since transportation networks are interconnected, disruptions can cascade across the metropolitan region.
Energy and Utilities
High temperatures increase electricity demand for cooling. This strain can:
Trigger blackouts
Reduce power plant efficiency
Overload transmission lines
Infrastructure located near coasts or rivers faces heightened corrosion, flooding, and storm damage, requiring extensive upgrades and investment.
Water and Sanitation Networks
Intense rainfall can overwhelm sewer systems, causing:
Combined sewer overflows (CSOs)
Contamination of surface water and groundwater
Public health risks from waterborne diseases
Drought stresses water treatment plants and distribution systems, forcing utilities to seek new supply sources or expand storage capacity.
Urban Mitigation Strategies
Cities play an important role in slowing climate change through mitigation, which refers to actions that reduce greenhouse gas emissions.
Low-Carbon Urban Design
Mitigation strategies include:
Expanding public transit, cycling lanes, and pedestrian networks to reduce car dependence
Increasing energy-efficient buildings through retrofits and green construction
Supporting renewable energy, such as rooftop solar and district energy systems
Encouraging compact, mixed-use development, which lowers vehicle miles traveled
These strategies not only reduce emissions but also improve air quality and overall urban livability.
Urban Adaptation Strategies
Because climate impacts are already occurring, cities must also invest in adaptation, which aims to adjust systems to reduce climate risks.
Green Infrastructure
Green infrastructure uses natural systems to manage heat and water. Examples include:
Urban trees that provide shade and reduce heat
Green roofs that absorb rainfall and lower building temperatures
This image shows the vegetated roof of Chicago City Hall surrounded by conventional rooftops and high-rise buildings. Green roofs help absorb rainfall, reduce stormwater runoff, and cool building surfaces, making them a key adaptation tool for climate-resilient cities. The image includes additional contextual detail about a specific city (Chicago), but the core concepts align directly with the syllabus focus on green infrastructure and climate adaptation. Source.
Permeable surfaces that reduce runoff and lessen flood risk
Wetlands and restored shorelines that buffer storm surge and erosion
These designs offer both environmental and social benefits, improving resilience while enhancing public spaces.
Climate-Resilient Infrastructure
Cities are upgrading infrastructure to withstand more powerful hazards.
Elevating electrical substations and transportation tunnels
Constructing sea walls, levees, and surge barriers
Relocating critical services away from high-risk zones
Enhancing early-warning systems and emergency response networks
Social and Governance Approaches
Because climate risks affect populations unevenly, adaptation must consider equity.
Prioritizing investments in underserved neighborhoods
Strengthening housing quality and ensuring access to cooling centers
Expanding community planning and public engagement
Coordinating across metropolitan governments for regionwide resilience
Cities also partner globally through climate networks to share data, innovate strategies, and secure funding for major climate initiatives.
FAQ
Climate change disrupts labour productivity, especially during prolonged heatwaves, which reduces output in outdoor and service-based industries.
It also increases operational costs for businesses through higher cooling expenses, insurance premiums, and supply chain disruptions linked to extreme weather.
Cities reliant on tourism may experience seasonal downturns if heat, flooding, or degraded air quality reduce visitor appeal.
Informal settlements often develop in marginal areas such as steep slopes, floodplains, or coastal edges where climate hazards intensify.
Housing materials are frequently low-quality, making structures more susceptible to collapse during storms or heavy rainfall.
Residents may lack access to drainage, cooling, reliable energy, and emergency services, limiting their ability to adapt or recover.
Climate-driven hazards can trigger internal displacement, pushing residents from high-risk zones such as coastal districts or flood-prone neighbourhoods to safer areas within the same city.
These shifts may increase pressure on housing markets in receiving zones, accelerating rent increases and intensifying competition for affordable homes.
Movement away from vulnerable areas can also reshape urban demographics, altering demand for services, transport, and infrastructure.
Local governments coordinate land-use planning, building codes, and infrastructure investment that determine how well a city withstands climate hazards.
They also guide adaptation by prioritising vulnerable communities, managing emergency responses, and supporting green infrastructure projects.
Partnerships with regional authorities, private developers, and community groups help governments secure funding, share data, and implement resilience strategies effectively.
Extreme heat and drought can disrupt agricultural productivity in peri-urban and rural regions that supply city markets, leading to higher food prices.
Flooding can damage transport routes and distribution centres, interrupting the flow of goods into dense urban areas.
Low-income households face heightened food insecurity when climate impacts increase costs or reduce availability, deepening existing social inequalities.
Practice Questions
Question 1 (1–3 marks)
Explain one way in which climate change increases the vulnerability of cities.
Question 1
1 mark for a basic statement; up to 3 marks for clear explanation with detail.
Award up to 3 marks for points such as:
• Climate change increases the frequency and intensity of extreme heat, placing strain on energy systems and increasing health risks. (1 mark for identifying heat risk, +1–2 marks for explanation of its urban impacts)
• Climate change leads to more extreme rainfall events, which overwhelm urban drainage systems due to high levels of impermeable surfaces. (1 mark for identifying flooding, +1–2 marks for explaining why cities are especially affected)
• Sea-level rise increases coastal flooding risk for cities located on deltas, river mouths, or coastal plains. (1 mark for identifying sea-level rise, +1–2 marks for explaining how urban location increases vulnerability)
Max 3 marks.
Question 2 (4–6 marks)
Discuss how both mitigation and adaptation strategies can help cities manage the impacts of climate change. Refer to specific urban processes in your answer.
Question 2
Award up to 6 marks:
• 1–2 marks for describing mitigation strategies
• 1–2 marks for describing adaptation strategies
• 1–2 marks for explaining how these strategies help cities cope with climate impacts
Credit use of examples but do not require them for full marks.
Indicative content:
• Mitigation strategies such as expanding public transport, promoting compact urban design, or increasing renewable energy reduce greenhouse gas emissions and slow long-term climate change. (1–2 marks)
• Adaptation strategies such as green roofs, permeable surfaces, and coastal defences reduce immediate climate risks by managing heat, stormwater, and flooding. (1–2 marks)
• Clear explanation of how these measures help cities, for example by reducing heat stress, preventing infrastructure disruption, or protecting vulnerable populations. (1–2 marks)
