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Cities are growing horizontally. And why is this a problem?

Imagine Lagos, in Nigeria, a city of 22 millions of people. What was once a small coastal town, just a few decades ago it exploded into a scattered megacity that spans more than 1.170 square kilometers. The rapid growth has put the most pressure on municipal services: less than 10% of people live in houses connected to sewage networks; less than 20% have access to running water. Many houses are in slums or informal settlements on the outskirts of the city. When cities spread horizontally instead of vertically, as happened in Lagos, spatial inequalities could worsen and the economy and natural resources could suffer even more.

Now imagine Lagos twice as big.

Lagos is one of many cities expected to grow exponentially over the next three decades, in population and in territory. Recent estimates show that the global urban area could increase 80% Come in 2018 e 2030, considering the constant annual growth rates.

The new World Resources Report (WRR), Upward and Outward Growth: Managing Urban Expansion for More Equitable Cities in the Global South, analyzes growth patterns of 499 cities using remote sensing. While cities that grow vertically through taller buildings are predominantly located in wealthy North American cities, Europe and East Asia, cities in sub-Saharan Africa and South Asia are growing mostly horizontally. These cities have fewer funding sources to manage their growth, but they are expected to shelter 2 billion more people even 2050. As we know last twodata released by the United Nations, the expectation is that only three countries – India, China and Nigeria - represent 35% of global urban population growth between 2018 e 2050. As the urban population grows, keeping the sprawling can lead cities to crises.

Lagos must see its territory at least grow in size until 2050 (Photo: Heinrich Böll Foundation / Flickr)

3 consequences of uncontrolled urban expansion

Failures in the proper management of territorial expansion not only exacerbate urban inequalities, but they also contribute to greater economic and environmental risks for the city as a whole.. From Mumbai to Mexico City, it is very common to see crowded favelas grow in size and density alongside high-rise developments, inaccessible and often empty. Municipal service networks fail to keep up with urban growth, and cities with limited resources tend only to react to development trends rather than territorial development agencies proactively planning for growth..

Some of the implications of this uncontrolled growth include:

1. Mgreater inequality

Like Lagos, many cities are already suffering from existing inequalities, inadequate provision of basic services and overstretched municipal capacities. The uncontrolled expansion of the territory exacerbates these difficulties. Low-income families typically move to the outskirts of cities in search ofaffordable housing. Nonetheless, the farther they are from the central region, the harder your lives can become. Families on the fringes of cities will spend twice as much money and triple the time to get around as families near their workplaces, schools and leisure in the city center. As a city spreads, local agencies often struggle to provide water., sanitation and electricity. citizens depend, then, the informal provision of services – such as water trucks and private garbage collectors, that can charge up to 30 times more than municipal agencies – or they are left without these services, affecting your health and quality of life in general. Only the richest can afford these strategies, leaving many urban dwellers underserved. Once these types of urban territorial development patterns are initiated, they have long-term effects on accessing opportunities., productivity and quality of life.

2. Economic tensions for the entire city

Research shows that as cities expand outward and population densities decline, municipal costs of providing public services increase. In Indian and African cities, services like paved roads, drainage and piped water drop drastically just five kilometers from the city. The investments associated with new infrastructure and the social costs of lacking it continue to increase as new urban areas are added.. Furthermore, expansion means more traffic jams, pollution and longer trips. the polluted air, driven mainly by the use of private cars and trucks, generates huge social and economic costs, as impacts on health and damage to crops. I'm Chengdu, and China, the economic loss generated by transport-related air pollutionregistered US$ 3 billion in 2013.

3. Environmental problems

Globally, the growth rate of urban territory far exceeds population growth. This often comes at a cost tothe farmland, ecosystem services and biodiversity, that contribute to food production and climate resilience. We are already seeing some of the fastest growing urban areas in low-lying coastal areas, flood plains, in places of high biodiversity and areas with water problems. The unrestrained development of these sensitive ecosystems could further strain natural resources and lead to disastrous seasonal monsoon floods in many cities in South Asia. Unregulated deforestation in cities like Bangalore, Jakarta and Mexico City, that are growing fast and have little running water and high water stress, is causing entire neighborhoods to sink. The situation is particularly worrying inJakarta, where experts say that, with rising sea levels, the city has just a decade to stop sinking before millions of homes are submerged.

Containing unplanned expansion in cities

These impacts are compounded by the fact that most of the horizontal growth currently taking place in Africa and South Asia is informal and unplanned., or in places where existing urban land use regulations are not enforced. Part of this expansion is beyond the control of cities, considering the natural increase in population and people who migrate from rural to urban areas in search of economic opportunities. But other challenges are points that cities can manage more proactively.

For example, distorted land markets can lead to speculative and fragmented development, where private owners, property developers and corrupt government officials disproportionately benefit from rising land values. fragile planning, ineffective land use regulations and certain market conditions are known to drive expansion, relegating affordable housing to unserviced or underserved locations on the outskirts of the city. Irregular conversion of agricultural land and absorption of peripheral communities result in informal settlements or slums disconnected from city services.

Although it is a huge challenge, some cities are already using innovative approaches to prioritize accessibility and manage urban sprawl. Cities in Mexico, Brazil and South Africa are driving new developments into already well-served and connected areas, instead of spreading out. Colombian cities, South Korea and India have progressively added new land in well-connected and maintained locations through partnerships with utilities and private companies to help with funding. Many cities are also working with communities in informal settlements to create affordable density with more flexible planning patterns and modernization initiatives..

The impacts of changes in land use policy in a city can last for many decades. Cities in Africa and Asia have a choice: start managing unsustainable horizontal sprawl today or watch problems get worse tomorrow.

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