What is happening?
- As the global population continues to grow, cities and towns are expanding much faster than rural areas, and countries around the world are urbanizing rapidly and as a result (graph below):
- The global population is expected to grow from 7.349 billion in 2014 to 9.725 billion in 2050.
- The global urban population is expected to increase from 54% of the total population in 2014 to 66% in 2050.
The ongoing growth in global population is mainly attributed to expanding urban population, which leads to increasing urbanization (from United Nations).
How is this related to climate?
- Urban areas are disproportionately responsible for climate change (image below).
- They consume over two thirds of the world’s energy.
- They create 70% of greenhouse gas emissions.
- People living in cities buy more food and other goods than people living in rural areas.
- Most cities have unsustainable infrastructure and public transportation systems, contributing to about one third of urban residents’ carbon footprints.
Urban areas contribute disproportionately to climate change, as evidenced by the carbon footprints of high-impact cities (from Miller via Moran and others, 2018).
- Urban areas are disproportionately affected by climate change.
- More than 90% of urban areas are coastal and are threatened by rising sea levels. It is expected that 800 million people will be affected by a 0.5 meter rise in sea levels in the next 30 years.
- Cities, like all other parts of the world, have already experienced, and will likely continue to experience, an increase in severe weather events, such as droughts, hurricanes and tornadoes. Because cities are more densely populated than rural areas, more people will be affected by these events at once.
- Cities suffer more from heat waves than rural areas do. This is known as the “urban heat island” effect and is caused by cities having more pavement, which absorbs and retains heat, and fewer trees, which provide shade and natural cooling.
- Mitigating climate change and its consequences will depend heavily on how urban areas respond. Some of the changes that can be made include:
- Transitioning to renewable energy sources, including hydropower, wind, solar, biomass and geothermal.
- Using more sustainable construction materials (instead of steel, concrete and glass) for new buildings and roads and updating existing infrastructure to be more sustainable.
- Urban planning in developing countries.
- It is expected that 90% of urbanization in the next 30 years will occur in developing countries. If urbanization is done sustainably from the beginning, serious causes and consequences of climate change can be avoided or at least reduced.
References and additional resources
- Beagen, B. “Building Resilience from the Ground Up: Indonesia’s Coastal Cities.” Urbanet. 2020. https://www.urbanet.info/building-resilience-from-the-ground-up-indonesia-coastal-cities.
- Borunda, A. “This Is What Cities Need to Do By 2050 to Meet Climate Goals.” National Geographic. 2019. https://www.nationalgeographic.com/environment/2019/09/zero-carbon-cities-future.
- “Extreme Weather and Climate Change.” Center for Climate and Energy Solutions. n.d. https://www.c2es.org/content/extreme-weather-and-climate-change/.
- Gustin, G. “More Than 100 Cities Worldwide Now Powered Primarily By
- Renewable Energy.” Inside Climate News. 2018. https://insideclimatenews.org/news/27022018/renewable-energy-cities-clean-power-technology-cdp-report-global-warming-solutions/.
- Miller, M. “Here’s How Much Cities Contribute to the World’s Carbon Footprint.” Scientific American. 2018. https://www.scientificamerican.com/article/heres-how-much-cities-contribute-to-the-worlds-carBon-footprint/.
- Moran, D., Kanemoto, K., Jiborn, M., Wood, R., Többen, J., and Seto, K. C. “Carbon Footprints of 13,000 Cities.” Environmental Research Letters, vol. 13, no. 6, 2018. https://iopscience.iop.org/article/10.1088/1748-9326/aac72a.
- Muggah, R. “The World’s Coastal Cities Are Going Under. Here’s How Some Are Fighting Back.” World Economic Forum. 2019. https://www.weforum.org/agenda/2019/01/the-world-s-coastal-cities-are-going-under-here-is-how-some-are-fighting-back.
- Torrey, B. B. “Urbanization: An Environmental Force to be Reckoned With.” Population Reference Bureau. 2004. https://www.prb.org/urbanization-an-environmental-force-to-be-reckoned-with.
- “Reduce Urban Heat Island Effect.” EPA. March 2022. https://www.epa.gov/green-infrastructure/reduce-urban-heat-island-effect#:~:text=%22Urban%20heat%20islands%22%20occur%20when,heat%2Drelated%20illness%20and%20mortality.
- United Nations. “Our Urbanizing World.” Population Division, Department of Economic and Social Affairs. 2019. https://www.un.org/en/development/desa/population/publications/pdf/popfacts/PopFacts_2014-3.pdf.
- Walton, B. “This Is How Cities Around the World Are Fighting the Water Crisis.” World Economic Forum. 2019.https://www.weforum.org/agenda/2019/08/the-next-urban-water-crisis-inadequate-data-clouds-the-forecast.
- “Why Cities.” C40 Cities. n.d. https://www.c40.org/why_cities.