A recent study revealed that, since 2014, marine heatwaves have become “the new normal.” The climate crisis is no longer a concern for the distant future. Extreme events are increasingly common; one only has to follow the news. While it may seem that public officials are being caught off guard, scientists have long warned of the need to focus on sustainable development.
Good examples are still few and far between, but they do exist. At COP26, a comprehensive guide featuring proven strategies to achieve urban cooling was launched.
Developed by the United Nations Environment Programme (UNEP), the guide projects that the energy needed for space cooling will triple by 2050.
Furthermore, it attributes this to a combination of reduced green cover, the thermal properties of materials commonly used for urban surfaces, and waste heat from human activity.
Going beyond merely identifying the problems, the handbook focuses on solutions by presenting dozens of examples and case studies as inspiration for urban areas—which are the most susceptible to heatwaves.
A greater distribution of green and blue spaces, improved ventilation, waste heat management, street trees, cool and reflective surfaces that prevent heat absorption, and using buildings to increase shade in public areas are among the guide's suggestions.
A few examples
Below, we highlight some of the case studies detailed in the guide:
- United States: The heat reduction services of urban tree cover in the United States are estimated at $5.3 billion to $12.1 billion annually. Globally, investing $100 million annually in street trees would give 77 million people a 1°C reduction in maximum temperatures on hot days.
- Seoul, South Korea: An effort to restore the Cheonggyecheon stream running through the city replaced 5.8 kilometers of elevated expressway covering the stream with a mixed-use waterfront corridor. The waterfront corridor reduced temperatures by 3.3°C to 5.9°C compared to a parallel road a few blocks away.
- Medellín, Colombia: Opted for green corridors. From 2016 to 2019, the city created 36 corridors, 18 along major thoroughfares and 18 along waterways, covering more than 36 hectares. Areas with green corridors have already experienced temperature reductions of up to 4°C.
- Paris, France: Paris is home to Europe's first and largest district cooling system. When the water temperature in the Seine River running through the city is below 8°C, this water is used to provide “free cooling.”
- Toronto, Canada: The city government implemented the world's largest lake-source cooling system. Commissioned in 2004, the Deep Lake Water Cooling (DLWC) system uses cold water from Lake Ontario as a renewable energy source.
- Guangzhou, China: The municipal government adopted regional centralized cooling as part of a modern, green, and eco-friendly urban center in the core area of the Pearl River New Town development. The local ambient temperature in the central area of Zhujiang New Town was reduced by 2–3°C compared to the use of distributed cooling systems.
For a better world for all
The guide highlights that low-income communities are typically the most vulnerable to heat. As a result, the negative impacts of extreme heat fall disproportionately on those least able to afford or access the necessary thermal comfort. “We need to transition to more equitable and sustainable ways of cooling our cities and making them livable for everyone,” the publication points out.
Read the guide Beating the Heat: A Sustainable Cooling Handbook for Cities.
Via CicloVivo.
This article was written by Marcia Sousa. The translation is powered by AI.
