2 Environment

This chapter explores the complex relationship between the natural and the built environments. We begin by looking at how nature influences the location of cities and shapes their design and layout. We then examine the infrastructure challenges that cities face and consider how urbanization contributes to air, water, and other forms of pollution. Next, we will explore the relationship between social inequalities and exposure to environmental toxins. The chapter concludes with a brief discussion of the problems posed by climate change.

Nature and the Location of Cities

Nature plays a major role in determining where cities will emerge and develop. Ancient cities were constructed in areas that had sufficient resources to produce a reliable surplus of food that could support a significant non-farming population.^[1] In order to grow enough food to sustain a large number of people, a year-round source of freshwater, fertile soil, and a relatively temperate climate are necessary. Ancient cities were usually located in warm weather regions along rivers or other water sources that could be used to irrigate fields.

During medieval times, cities developed along trade routes, which tended to follow major waterways. As the industrial revolution took hold, water continued to play a key role in determining where cities would be established. Rivers provided a power source for mills and factories. The navigability of rivers also helped determine where populations would settle. The cities of Wilmington, Delaware; Philadelphia, Pennsylvania; and Trenton, New Jersey; are all located along the Delaware River. Each city was established at a portage site – a section of river that is not easily passable because of rapids or other obstacles.^[2] In these sections of the river, boats had be taken out of the water and transported overland to get past the rapids or falls. These sites became prime spots for urban development, because the bottlenecks created by the river’s natural obstacles caused waterway travelers to have disembark and stay in the area for a while.

Although cities were established in areas that have an abundance of natural resources, those resources are not necessarily used to benefit the local urban population. Some cities are export hubs that facilitate the transfer of a region’s natural wealth to other parts of the world. In nations that were colonized in Africa, Asia and Latin America, Europeans developed cities along coastal areas and rivers in order to extract and export resources abroad.^[3] One of the legacies of colonization in Africa and Latin America was the establishment of a primate or primary city, which served as an export hub and was the undisputed capital of economic and political power for an entire nation.^[4] Primate cities are at least twice the size of the next largest city in the country and at least twice as significant economically. Although primate cities exist in countries throughout the world, in formerly colonized nations, economic development and wealth are concentrated within the primate city often at the expense of other cities and regions. The concentration of wealth and development can put a strain on local resources. Export-dependent economies can also degrade local environments. Agriculture, mining, and other resource extractive industries can pollute air, land and waterways while providing little economic benefit to the cities and regions where they occur.

How Nature Shapes a City

From ancient Pakistani and Indian cities to the wide streets of modern-day Chicago, most urban areas are laid out in a grid or crisscrossing rectangular street pattern.^[5] To accommodate the grid and the parcels of developable land generated by this street pattern, hilly areas are flattened, creeks and waterways are diverted underground, and wetlands are filled in. Simply looking at the breaks in the grid pattern on a street map will reveal some of the city’s original topography, the areas where mountains, canyons or rivers could not be engineered into a flat, developable landscape and had to be incorporated into the built environment rather than forced to comply with it.

Some cities are now seeking to reclaim natural landscapes that were once considered barriers to development. The San Antonio River has become a key attraction in San Antonio, Texas. The Riverwalk, a network of pedestrian paths laid out along the riverfront, is lined with shops, restaurants, and entertainment venues.^[6] Decades ago, the San Antonio River was associated with destruction, because periodic, catastrophic flooding led to death and devastation. After a flood control dam and diversion canal were constructed, the river came to be considered an asset to the city and was developed as a major tourist attraction.

Natural and geographical features also shape cities in more subtle ways. The aesthetics and design of a city’s built environment are influenced by its natural setting. Vernacular architecture refers to structures that are designed and constructed in keeping with local cultural traditions and their natural surroundings.^[7][/footnote] A significant number of buildings in cities around the world are considered vernacular architecture. These buildings are not designed by professionals and rely upon materials and techniques that are indigenous to particular area. Vernacular dwellings accommodate the rhythm and flow of daily life, support cultural traditions, and intersect in a meaningful way with other structures in a community in order to fulfill the public’s needs.

Urban vernacular architecture reflects and shapes the environment and culture of a city. The traditional form of housing in Beijing, China was the siheyuan, a complex of four buildings oriented around a central courtyard.^[8] These courtyard compounds housed extended family members and provided a balance between the private spaces in the interior rooms and the communal area of the courtyard where household tasks were carried out and family gatherings took place. A compound sometimes contained multiple courtyard complexes. The height and size of the dwellings lining the four sides of the courtyard were determined by their directional orientation, with the largest and tallest pavilion located on the north/south axis, and smaller, less important buildings constructed on the east/west sides. This design maximized the amount of natural light and heat the courtyard compound received during Beijing’s cold winters, and the overhanging eaves of the pavilion and deciduous shade trees planted within the courtyard were designed to keep the compound cool during the city’s hot summers. The prescribed heights and depths of the various compound pavilions and the layout of courtyards along a neighborhood’s lanes and alleyways allowed for maximum sunlight to reach neighboring complexes without being shaded by the structures in adjoining compounds.

The traditional architecture of Shiraz, Iran, contains many features that help keep buildings cool in a hot, semi-arid climate.^[9] Like the vernacular styles in Beijing, buildings in Shiraz contain inner courtyards. These courtyards have a small pool or water feature, which helps cool the open space and surrounding rooms. The oldest buildings in the city were constructed with wind catchers, which are tall chimneys set near the entryway of the home that circulate air through an underground pool and create a natural air conditioning system. Like vernacular styles in other cities with hot climates, the homes in Shiraz have thick, mud-brick walls and small high windows that allow for air flow, but prevent rooms from becoming overheated.

While this traditional building design keeps the house cool by incorporating passive solar elements, most Iranians today use swamp coolers during the hottest times of the year, even if their homes were built with natural cooling elements.^[10] A study conducted in the city of Yazd measured the temperature in various rooms in vernacular homes during different times of day. During the hottest time of day, the rooms remained cooler than outside, but only the basement rooms stayed cool enough to be considered comfortable. Traditionally, Iranians rotated their living spaces seasonally. The main living rooms were moved to the basement during the hottest times of the year. Today most Iranians use air conditioners, because moving rooms seasonally is inconvenient and the damp basement air is considered unhealthy and unappealing. In this case, the vernacular designs can effectively and sustainably cool homes in a hot climate, but the cultural traditions involved in maintaining that system no longer fit with most people’s daily lives.

Urban Infrastructure

Although cities are located in areas with relatively abundant natural resources, the provision of food, water, waste, and sewage disposal to a large, concentrated population requires far more resources than are contained within a city’s immediate boundaries. While cities only occupy 2% of the earth’s land surface, they consume 75% of the world’s natural resources.^[11] One way to estimate the amount of productive land that a city requires to meet the needs of its population is to calculate its ecological footprint.^[12] The ecological footprint measure is a tool that was developed to measure the average amount of productive land and water resources that a household, city, region, or country uses based upon its overall consumption patterns. A footprint measure takes into account all of the land/water resources that are necessary to support the energy, food, housing, and transportation needs of a population. Footprints are calculated in global hectares per capita. The footprint measurement is a useful way to compare the ecological impacts of various places. For example, in 2017, the United States had an ecological footprint of 8.04 hectares/person, while Afghanistan’s footprint was only 0.66 hectares/person.^[13] The footprint measure can also be used to track the progress that a city or region makes toward becoming more ecologically sustainable. Calgary has a footprint that exceeds the Canadian national average, so the city began using the ecological footprint measure to assess its development plans and to chart more sustainable pathways forward.

One example of how a city’s ecological footprint far exceeds its geographical boundaries is the New York City drinking water system. New York City’s drinking water is supplied by a complex system of reservoirs, some located 125 miles away.^[14] The eighteen reservoir system and its surrounding watersheds occupy nearly 2,000 square miles. Water is carried to the city through a system of aqueducts, the largest of which is thirteen feet wide and eighty five miles long. Due to the age of the system, approximately 36 million gallons of water leak each day from cracks in the aqueducts and delivery pipes, a loss equivalent to 3-6% of the city’s daily water supply.^[15] The problem is even more severe in other cities. London loses about 25% of its daily water supply due to leaks in its system, and Johannesburg loses 30%.

Despite its large footprint and flaws, the fact that New Yorkers can turn on a tap and have access to a safe, reliable water source is a major feat. Too many urban residents lack access to basic infrastructure, such as running water, sewage, or adequate housing. The United Nations uses the term slum to refer to a household that lacks access to running water or sanitation, has precarious rights to their housing or land, lives in a substandard dwelling, and/or a house that is overcrowded.^[16] In 2000, at least one billion people worldwide lived in these conditions.

The term slum, which is used by the United Nations and other international development organizations, can be problematic. Slum is considered a pejorative in most countries, although in India it is used by the urban poor as an empowering term. The phrase informal settlement is often used as a euphemism for slum, but this term refers to a specific type of community where members do not have secure title to the land where they have settled and built their homes. Informal communities refers to the social and legal status of the residents, while the term slum encompasses both social and economic deprivation.

Half of the urban populations in Africa, Latin America, and Asia live in slums or informal settlements.^[17]  Many homes in these communities are not connected to municipal water systems, so family members have to draw water from a communal tap if there is one nearby or purchase it from a private seller. Buying water from a private seller is ten to twenty times more expensive than paying for municipally supplied tap water. Since most households that lack running water are poor, purchasing water places an extra economic burden on families. Additionally, it takes time to transport water, and when a resource is so costly, it’s used sparingly, often putting the family at risk for dehydration and other health problems.

More than 2.6 billion people worldwide lack access to sanitation, more than twice the number that lack clean, running water.^[18] Connecting homes to a municipal sewage system can be costly, but the Orangi Pilot Project in Pakistan developed a low-cost method to connect households to existing sewage lines by training community residents to design, engineer, install, and maintain the lines within their settlement.^[19] By relying on local labor, the project was able to connect families to sewage lines at one fifth of the normal cost, and community members gained training and skills.^[20] Access to clean water and sewage are not just problems in lower-income countries. In the urban United States, most residents have access to municipal water, but it comes at a cost. The poorest urban residents are often faced with the difficult choice of deciding whether to their pay their rent or utility bills. In 2014, the United Nations High Commission on Human Rights condemned the city of Detroit for issuing water disconnection notices to more than 30,000 residents who had fallen behind on their bills, noting that if a resident is truly unable to pay, cutting off their water supply is a violation of their basic human rights.^[21] Homeless residents also face challenges getting access to water and sanitation.^[22] Public restrooms can be difficult to find in many urban areas, and relieving oneself on the street or sidewalk is considered a criminal act in most cities.

The challenges of providing water, sanitation, and adequate housing to urban residents worldwide are daunting, but the collective organization, knowledge, and ingenuity of people living under inadequate conditions has generated some creative and sustainable solutions. Slum Dwellers International is a group of informal settlement residents that began in India in the 1980s.^[23] This female-led group initiated a savings program where each household in the community set aside a small amount of money that was pooled together to finance and leverage loans to construct community-wide improvements. In the city of Manila in the Philippines, the municipal water company agreed to extend underground water lines to the edges of informal settlements if community organizations took responsibility for installing water pipes to connect each block to the municipal line and agreed to collect payments for the services, which saved residents money by not having to purchase water from private sellers.^[24] Some blocks decided to install a communal water tap that multiple households could access. Communal solutions to water and sewage provision are often more cost-effect than installing services at the individual household level. In Seattle, Washington, the Low Income Housing Institute (LIHI) created an Urban Rest Stop downtown where homeless people can access restrooms, showers, and laundry facilities.^[25] LIHI now operates three urban rest stops around the city.

Providing basic services to its residents isn’t the only infrastructure challenge that cities face.  Existing infrastructure needs to be maintained, and aging systems may produce environmental problems. More than 850 towns and cities in the United States have a combined sewage overflow system, which means that rainwater is mixed with industrial and household wastewater and processed through the same sewage and water treatment system.^[26] Many of these sewage systems were built before flush toilets became widespread, and they were initially designed to divert the garbage, animal and human wastes that were left in open sewers of industrial cities away from streets and homes during large rainstorms.^[27] The early sewage systems emptied the rainwater and wastes directly into a nearby rivers, bays, lakes, or the ocean. Today, wastewater is processed through a complex treatment system before it enters a waterway to remove hazardous bacteria and sludge. But in combined sewage overflow systems, heavy rain or snowmelt overwhelms the system. When the volume of rain and wastewater become too large for the sewer pipes and treatment system to handle, excess untreated wastewater ends up being released untreated into waterways.

Combined sewage overflow systems are a major source of water pollution in the United States.  In New York City, the system experiences overflows during half of all rainstorms, resulting in about 40 billion gallons of untreated wastewater flowing each year directly into the harbor.^[28] Releases from combined sewage overflows have been tied to algal blooms, degradation of drinking water supplies, fish and marine life kills, and spikes in gastrointestinal illnesses.^[29] Cites have come up with a variety of solutions to this problem. New York is constructing underground reservoirs that will temporarily store excess wastewater until volumes return to normal levels and the system can process it, and Portland, Oregon’s Big Pipe project created a series of underground tunnels that slowed the flow of wastewater and reduced untreated wastewater releases by 90%. ^[30]

Air Pollution

Urbanization not only impacts water quality, but it also produces air pollution. In urban areas, air quality is degraded by burning fossil fuels for transportation, energy generation and industrial production. According to the World Health Organization, 80% of people living in metropolitan areas breathe air that exceeds global pollution thresholds.^[31] Air pollution is not equally distributed across the globe. Ninety eight percent of urban residents in low and middle income countries are exposed to poor quality air, while only 56% of city dwellers breathe dirty air in higher income countries. Cities in India, Pakistan, Bangladesh, and China currently have some of the highest levels of air pollution in the world. In the United States, the cities with the poorest air quality are concentrated in California and the Midwest. There are many factors that contribute to a city’s air quality including its geography, climate patterns, design, industrial mix, transportation and energy infrastructure. Breathing polluted air increases the risk of heart and lung diseases, stroke, and asthma.^[32]

To improve outdoor air quality, cities can upgrade infrastructure, regulate industrial emissions, or encourage residents to change personal habits. In China, where air pollution causes over a million deaths each year, the government is switching from coal fired plants to cleaner energy sources, improving emissions standards for cars, requiring higher quality gasoline, and installing air scrubbers and other anti-pollution devices in plants.^[33] Other countries are taking less comprehensive, but significant steps to reduce urban air pollution. Bangalore, India, achieved a 20% reduction in vehicle-based pollution by running buses on natural gas instead of diesel fuel and encouraging residents to take public transit.^[34] European cities like Zurich, Helsinki, and Copenhagen are restricting cars in certain areas, constructing bicycle and pedestrian infrastructure, and improving public transit.

Air quality can also be improved by making informed and deliberate decisions about where and how urban development occurs. People who live in more densely populated neighborhoods use less gasoline and electricity than their suburban counterparts do.^[35] Even when urban and suburban residents have similar commute times to work, suburban residents end up driving more. The low-density, auto-dependent design of most suburban communities means that residents have to drive to accomplish other daily tasks like shopping, visiting with friends and family, or going out. Suburbanites tend to live in larger, single family homes, which results in greater electricity use, especially for heating and cooling. In the United States, the cities where summer temperatures require air conditioning are located in parts of the country where urban development occurred later, which means that these cities are lower-density, more suburbanized and auto-dependent; therefore, they consume more electricity per capita than older cities located in the colder regions of the U.S.

In addition to outdoor pollutants, some urban residents around the globe are also exposed to air pollutants inside their homes. Some households cook over open fires using wood, animal or crop wastes as fuel, which causes carbon monoxide and particulate matter to be released. The World Health Organization estimates that up to one hundred times the recommended amounts of soot and other particulates are found in poorly ventilated cooking areas.^[36] Since women are primarily responsible for household tasks like cooking and childcare, women and young children are far more likely to be affected by poor indoor air quality. About half of all deaths of children under 5 years old from pneumonia are caused by indoor air pollution, and four million people die worldwide each year from exposure to these toxins. Providing households with access to cleaner fuels and better cooking technology could help alleviate the suffering and death caused by indoor air pollution.

Toxins and Environmental Justice Movements

Industrialization expanded and intensified the urbanization process. The growth of large-scale manufacturing required a massive influx of laborers, which led to dramatic population growth in cities. The energy and raw materials that fueled factories left long-lasting ecological scars in communities where they were mined, harvested or produced. Manufacturing also produced waste on a scale that far surpassed previous modes of production. Much of that waste was discarded in dumps on or near factory sites or discharged into urban waterways. The sanitary movements that emerged in the late 19th century focused on disposing of household wastes, keeping drinking water systems free of human wastes and other disease-causing contaminants, and cleaning-up the public spaces of the city.^[37] Less visible industrial waste products, like dioxins or heavy metals, were ignored, because their impact on human health had not yet been established. As a result, many industrial cities were contaminated with manufacturing wastes that posed long-term threats to human health.

The 1962 publication of marine biologist Rachel Carson’s book Silent Spring raised awareness about environmental impacts of pesticides and other chemicals.^[38] Silent Spring documented how pesticides like DDT can negatively impact ecosystems and can bio-accumulate in toxic levels as they move up the food chain. During the 1960s, public opinion about the environment began to change. In 1969, the Cuyahoga River, which runs through Cleveland, caught fire when a spark from a passing train ignited an oil slick on top of the waterway.^[39] This was not the first time the river had caught fire, and the event did not initially cause a local uproar. The Cuyahoga had long been used as an unregulated, industrial waste dump, but local officials led by Mayor Carl Stokes, the first African American elected to lead a large U.S. city, had recently allocated money to begin cleaning up the waterway. Clevelanders had previously viewed the river’s contamination as an unsightly, but necessary trade-off for the city’s flourishing industrial economy. By the late 1960s, manufacturing employment had begun to decline, and Clevelanders started to rethink their city’s relationship to the troubled waterway. When Time magazine published a story about the river fire months after it happened, it captured national attention and helped spur federal environmental legislation including the founding of the Environmental Protection Agency and the passage of the Clean Water Act.

In 1977, residents of a working-class neighborhood in Niagara Falls began noticing sludge seeping into their yards and basements and started experiencing new health problems. Their neighborhood was built atop an abandoned canal that had been used as a chemical disposal site for decades.^[40] In the 1890s, William Love halted construction on a canal project after he ran out of money. The five-mile-long ditch became a dump site for the Hooker Chemical Company, which eventually filled in the land and sold it to the Niagara Falls school district for one dollar in 1953. The district built an elementary school on top of the disposal site and a suburban development grew-up around it. Residents of the area had noticed occasional problems from the 21,000 tons of buried waste prior to the 1970s, but repeated heavy snowfalls and melts in the late 1970s caused major leakages.

The state and federal authorities investigated and found significant land and groundwater contamination.^[41] They also documented increased rates of miscarriage, chromosomal breakage, and liver damage in neighborhood children, but environmental regulators were hesitant to take action until they could definitely prove that these health issues were caused by the dioxins, the benzene and the other chemical compounds present in Love Canal. They instead issued guidance to residents warning them about potential pregnancy risks and recommending that they avoid their basements and not plant edible gardens in their yards. The Love Canal Homeowners Association (LCHA), a local renters association and community groups organized to demand further action. The homeowners, in particular, were very vocal. They were concerned that declining property values would leave them unable to sell their homes and afford to move to a safer community.

The organizing efforts at Love Canal lasted for years. Most of the advocacy was led by women. Lois Gibbs was a housewife and president of the Love Canal Homeowners Association. She recruited a respected female scientist to help the residents conduct a community health survey. The survey found increased risk of miscarriage, urinary diseases, asthma, birth defects, and central nervous system problems among residents. In addition to community-based research, activists from the LCHA, renters’ organizations, church groups, and the NAACP staged protests and even once barricaded EPA officials in the LCHA office for five hours. Eventually, hundreds of families were evacuated and compensated. The Love Canal disaster spurred the passage of the Superfund law, which empowers the federal government to designate contaminated sites, clean-them up and recoup the mitigation costs from the polluters.

In 1982, the residents of Warren County, North Carolina, made headlines when they laid down in along a highway to physically block trucks carrying soil contaminated with PCBs (polychlorinated biphenyls) that was headed to a local landfill.^[42] Nearly five hundred residents were eventually arrested protesting the state’s decision to site a toxic waste landfill in their community. This was the largest civil rights and mass civil disobedience campaign since the 1960s.

The controversy in Warren County began years earlier when a Raleigh-based company illegally dumped PCBs along 240 miles of roadway across the state. The owner of the company was arrested and jailed, and the federal and state authorities began removing contaminated soils and searching for a location to construct a landfill where the soil could be safely disposed of. They eventually selected a small community in Warren County, which was the poorest county in the state and is 65% Black. Warren County is relatively low-lying and the water table is just five to ten feet below the ground, raising concerns that the contaminants could potential leak in well-water.

Given the physical unsuitability of the landfill site, residents believed their community had been chosen because it was low-income and predominately Black. The EPA and state authorities asserted that the siting process had been fair and transparent. But wealthier places have more political sway and are often able to stop unwanted uses from being sited in their communities. Poorer communities are sometimes perceived to be so desperate for economic investment and jobs that they will tolerate potentially harmful industries. The citizens of Warren County challenged that perception.

While they were unable to stop the construction of the landfill, the Warren County protests ushered in a new era of environmental activism that was led by people of color and focused on improving the environments where people live, work, and play rather than preserving pristine areas or saving endangered species.^[43] This new movement framed their struggle as a fight for “environmental justice.” A study conducted by the United Church of Christ in 1987 found that the majority of toxic waste sites were located in low-income communities and in communities of color. This landmark study documented the “environmental racism” inherent in siting of unwanted land uses. In 1991, the first national people of color environmental leadership conference was held.

The environmental justice movement believes that everyone has a right to live in a safe, healthy community. The movement focuses on improving the actual environments in the urban and suburban communities were people live, work and play. Like the residents of Love Canal, environmental justice advocates believe that polluters should bear the burden of proving that the toxins they produce and discard are safe, instead of communities having to wait until a definitive scientific link can be found between the contaminants in their neighborhood and their health before authorities take action. Activists believe that industry should adopt a credo of doing no harm. They also believe communities should have a say in the decisions that impact them. They want transparency and input into decision-making about the siting of potentially toxic land uses, just as Warren County protesters were fighting for.

The environmental justice movement seeks to remedy the disproportionate health burden that communities of color and low-income communities bear. While not all decisions about where wastes are stored or polluting industries are located are made with racist intent, data clearly shows that the costs of energy production, industrialization, and consumerism are not borne equally. Those who benefit the least often bear the greatest cost, while those who have the largest environmental footprint bear little to none. For example, it is estimated that between 60-80% of uranium in the U.S. is mined on tribal lands, yet indigenous people receive little benefit from the nuclear power plants and weapons industry it fuels.^[44] On the Navajo reservation, cancer rates doubled from 1970-1990, and 27% of Navajos had high uranium levels detected in urine samples compared to 5% of the overall population.^[45]

Women play a major role in environmental justice movements.^[46] Women of color often take on leadership positions in these grassroots groups. As caregivers, women are more likely to notice the impacts that pollutants have on their family’s health. Lois Gibbs’ activism began after her son experienced health problems connected to the contaminants dumped at Love Canal.

There are more than a thousand local environmental justice groups across the United States. The movement has won some considerable gains and made inroads to federal policymakers. The Environmental Protection Agency now has an office of environmental justice. But environmental racism still persists.

Climate Change and Cities

The Earth’s climate has varied over time. But the planet warmed or cooled over a span of thousands of years. Once the planet begins to cool or warm, it can trigger feedback loops that accelerate climate changes.^[47] For example, as Arctic permafrost thaws due to warming temperatures, methane and carbon, two greenhouse gases, are released into the atmosphere. Greenhouse gases cause further warming by trapping heat in the atmosphere. During the last Ice Age, there were 190 parts per million of carbon dioxide in the atmosphere. That increased to 280 parts per million during the current warmer cycle we are in. The rate remained relatively stable over thousands of years until industrialization began. Then the carbon dioxide concentration in the atmosphere increased to 400 parts per million. Global temperatures have risen by one degree Celsius in the past 150 years.

The main cause of the accelerated climate changes we are experiencing is greenhouse gas emissions from our industrialized societies. Urbanization is a key driver of climate change.^[48] Seventy percent of emissions originate in cities and towns. Urban populations are growing around the world. In 1970, only 18% of the Chinese population lived in urban areas; today more than 40% of the population lives in cities. This increase is equivalent to the entire population of the United States moving from rural to urban communities in just twenty years. Although China has a significantly smaller ecological footprint than the U.S. does, urbanization nonetheless increases greenhouse gas emissions.

Cities are also vulnerable to the impacts of climate change. Since most cities are built near coastal areas or waterways, flooding due to storm surges or sea level rise can threaten people and structures. Some of the most populous cities in the world, including Tokyo, New York, Hong Kong, London, Kolkata, and Buenos Aires, could see increased flooding in the very near future. Climate change can cause other challenges for cities. Heat waves can be devastating in communities that lack green space. Temperature changes and drought can compromise water sources, cause crop damage and impact food supplies, and damage existing infrastructure. Older cities are also saddled with legacy infrastructure that was built decades or even centuries earlier that can be difficult to upgrade to accommodate more climate-friendly technologies.

However, cities can also play a key role in mitigating climate change. The concentration of knowledge and power in urban areas can spur innovations and create the political will to adopt climate-friendly policies. The density of urban places makes it easier to design and implement carbon-neutral transportation networks and energy systems. Cities also facilitate mobilization. Grassroots organization and pressure is pivotal for creating lasting social change.

One of the most all-encompassing efforts to address climate change is the construction of model eco-cities.^[49] The notion of a built-from-scratch, utopian city is not new. The British urban planner Ebenezer Howard designed the Garden City in the late 1800s, and a number of towns and communities in Europe and North America were developed using his concepts. China has unveiled plans to address urbanization, in part, by constructing new eco-cities. One of the planned cities is Wanzhuang, which would replace the existing city of Lang Fang and connect it with surrounding villages. The plans call for preserving agricultural lands, creating a public transportation loop, and using renewable geothermal energy sources. Plans for establishing brand-new eco-cities like Wanzhuang are often walked back once construction begins. Abu Dhabi, one of the United Arab Emirates, announced plans to build a completely carbon-neutral town called Masdar City.^[50] Masdar City would be a hub of clean technology businesses and research, would use green building methods, encourage the use of alternative transportation, and be powered by solar and other renewable energies. Since construction on the town began, environmental sustainability goals have been reduced and the timelines for completion extended. While eco-city projects can provide inspiration and innovation, the promises often fall short.

Not every effort to combat climate change has to involve a complete overhaul. Puerto Princesa City in the Philippines set a goal to reduce its climate emissions by 10%.^[51] That reduction was achieved by making a series of small but meaningful changes. They turned streetlights off an hour earlier, shut down air conditioning systems in buildings during lunch hour, and installed a biogas plant that transformed organic wastes into energy that was used to power electric scooters and vehicles in the city’s fleet.

Cities are not only planning to reduce greenhouse gas emissions, they are also preparing to adapt to the impacts of climate change. Kansas City, Missouri, created an Extreme Heat Program (EHP) in 1980 after the city experienced 16 consecutive days where temperatures exceeded 102˚F (38.9˚C).^[52] The EHP runs a heat relief hotline and fan distribution program. They also worked with the local public health department and National Weather Service to develop and issue heat advisories that would trigger responses like opening cooling centers and staffing the hotline. The EHP evaluates its response each season and creates new initiatives to address gaps in its response. For example, some isolated elderly and disabled residents who were particularly vulnerable to heat-related illnesses were not responding to heat advisories and warnings. The EHP has made an effort to reach out to vulnerable populations through local organizations that serve these communities.

Toledo, Ohio, was built on a wetlands and is prone to flooding.^[53] Northwestern Ohio has experienced increased precipitation due to climate change. The city has adopted green infrastructure techniques to absorb storm water runoff and reduce flooding. On a small scale, green infrastructure can include planting rain gardens or creating bioswales that are designed to channel runoff to natural areas where it can be absorbed. On a larger scale, green infrastructure might include restoring wetlands and flood plains in flood-prone areas. The city calculated the cost of implementing a green infrastructure program and discovered that it would be economically beneficial to the community when compared to the potential losses from increased flooding.

In Miami, sea-level rise threatens some of the most expensive homes in beachfront areas.^[54] Some homeowners have increased the heights of their seawalls, and new buildings are raised several feet to accommodate for rising sea levels and potential flooding. However, climate change is also impacting neighborhoods farther inland. Liberty City, a low-income, predominantly Black community, is seeing rising housing costs and gentrification pressure as Miamians seek out property insulated from the effects of climate change. Liberty City residents have created a land trust that will help keep a portion of the housing permanently affordable.

Nature and the City

Early scholars writing about life in the industrial city rarely considered the relationship between nature and the urban environments. Frederick Engels vividly documented the contaminated settings that poor and working class urban residents in England lived and died in, but he did not examine how capitalism and urbanization impacted the environment.^[55] By the mid to late 20th century, urban theorists had begun to visualize the city as a complex system of inputs and outputs.^[56] Natural resources went into the city and wastes came out, each impacting the environment.

During the 1970s, environmental movements reshaped the way we think about nature and human activity. Human processes and built environments are not separate from their natural surroundings, but rather deeply intertwined with them. Urban political ecology views urbanization as a social, political, and ecological process that impacts both the urban and rural places.^[57] In other words, how nature is used to produce the built environment, the impact that urbanization has on natural resources, and how the costs and benefits of these processes are borne by different communities within urban areas are all determined by our political, economic, historical, and cultural systems. This approach allows us to see nature as an integral part of the urban system, rather than simply viewing it as something that is fed into and spit out of it.

Summary

Urbanization is not simply the inverse of nature. Instead, urban regions are fundamentally shaped, constrained, and co-produced by their natural environment. Natural resources determine where cities are located and influence their design. The ecological footprints of cities are much larger than their official boundaries, and the quality of the infrastructure provided in an urban region can have a substantial impact on both the environment and the health of the region and its residents. Water and air pollution degrade the quality of life in many cities. These problems are exacerbated by urban design. Lower-density development leads to increased energy usage and greater vehicle emissions.

In addition, not all urban residents have equal access to clean air, toxin-free neighborhoods, and clean water. Environmental justice highlights how communities of color and low-income people have borne a disproportionate burden of the toxins and pollution produced by cities. Another challenge cities face is climate change. Mitigation efforts can help curb the onset of climate change, but cities will also have to adapt and become more resilient as climate patterns change. Seeing the city as part of the larger natural environment, rather than simply as contrary to it, helps us understand the fundamental role that natural systems play in urban life.