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The Environmental Effect of Cities

What happens to the environment when man-made concrete jungles replace complex natural ecosystems?  The terrain changes, habitats destroyed, and water cycles are altered causing flash floods, increased temperatures, and dangerous levels of air pollution. Many of the challenges facing cities right now are directly related to the environmental destruction involved in developing a city. For example, poor air and water quality, lack of water access, improper stormwater management, waste-disposal issues, and high energy consumption are all challenges caused or enhanced by environmental degradation. When green spaces, such as parks, are cleared away to make room for homes and buildings, the natural systems that moderate temperature, airflow, and water cycles are degraded. But, that doesn’t mean cities are inherently destructive, it’s how we build and manage our cities that matters. 

Despite the many problems with cities, the reality is that the world is rapidly urbanizing. With over half our population living in urban areas, cities are responsible for 75% of global carbon emissions (primarily from buildings and transportation). More cars means more air pollution, more homes means more energy consumption, more people means more waste and in order to accommodate for development, we cut down trees and divert rivers. Ironically, the environments we’re degrading serve essential roles for making the planet livable. Making cities more sustainable is not just an environmental issue, it’s a social and economic issue. It is in all our best interests to make cities more sustainable as a strategic plan to build resilience towards climate change. Making cities more sustainable by implementing solutions that reduce the impacts driving climate change also makes cities more adaptable. For example, increasing urban green spaces helps sequester carbon (a leading factor driving climate change) and increases a city’s capacity to deal with extreme weather events such as flooding by absorbing much of that water. 

Impacts of Urbanization 

Urbanization has substantial consequences on the local environment. Ecosystems are destroyed to make way for construction and cities create barriers for migrating species. Dark, concrete buildings retain heat, creating heat islands that significantly increase temperature, affecting the local climate, water quality, and air quality. Replacing soil with concrete roads and sidewalks impedes the earth’s ability to store water making storm water and flash floods more destructive and droughts more intense. Congestion increases air pollution and loss of green spaces reduces nature’s ability to filter CO2 costing billions per year. However, studies show the impact isn’t limited to urban areas but actually affects global climate patterns. 

By modifying essential ebbs and flows of heat, water, gases, and aerosols, urban areas actually affect the regional and global climate by changing the composition of the atmosphere. So it isn’t just important to make cities more sustainable for urban dwellers, it has implications for global climate change as well. 

Social and Economic Impacts

Climate change related disasters account for billions of dollars in damages per year. In 2019 alone there were 15 climate disasters that cost over $1 billion and seven of those cost over $10 billion in damages. And these figures only account for insured losses! Between human life lost, property damage and disruptions to the economy, making cities environmentally friendly is well worth the investment. 

Cities are particularly susceptible to climate change because of the high density of humans. And as climate emergencies increase, it is often the most vulnerable populations who suffer the worst consequences. Generally, marginalized communities don’t have access to the same services and infrastructure as wealthier neighbourhoods and have less capital to stock up on supplies beforehand and rebuild afterwards. So, when a climate disaster hits, cities are particularly vulnerable and disadvantaged communities are the most affected. In order to work efficiently, urban sustainability and resilience initiatives must specifically consider what works for those who are most vulnerable. 

The Way Forward 

Inherently, cities don’t have to contribute to climate change. With innovative designs, city planners can increase sustainability while making their city more efficient and resilient. A notable example comes from Bangkok, Thailand, a city that is dangerously exposed to rising water levels. To address this, the Chulalongkorn University park uses innovative design to capture and store water from floods and uses it for irrigation during the dry season. Not only does capturing the water prevent flood damage on the park property, retaining the water mitigates flood risk to the rest of the city and Thailand’s largest green roof, housed on the park’s grounds, helps keep temperatures down!  

Another example comes from Medellin, Colombia where the ‘Corredores Verdes‘ project has successfully lowered the city temperature by 2 degrees celsius by planting almost 9,000 trees and 90,000 plants along strategic locations. In addition to lowering the temperature, this initiative has employed 75 people from disadvantaged backgrounds, sequestered carbon through photosynthesis, and provided biodiversity corridors for wildlife to cross the urban space. 

These two examples show how investing in nature-based solutions can change the game for the environmental impact of cities and their livability for humans. There are many strategies to increase urban sustainability. Installing green roofs, growing urban forests, painting roofs and roads white, innovating water management, and utilizing sustainable building materials (read more on construction here) are just some strategies that will save taxpayers millions in emergency response.  

Conclusion 

Cities have detrimental effects on the surrounding and global environment. As our world becomes increasingly urban, addressing city-specific challenges is increasingly important. Applying nature-based solutions to mitigate environmental damages makes cities more resilient to climate change, increases quality of life, and provides concrete economic benefits. To accommodate a growing urban population, city planners should learn from each other and collaborate on multidisciplinary solutions that respect nature.