Heat Island Effect
BUILDINGS & ENVIRONMENT
Temperature is higher in cities than in surrounding landscapes or in rural areas due to the densely built environment. The surfaces of buildings, paved streets and squares can be heated up extremely on summer days and radiate at night. We call this global warming issue as urban heat island (UHI) effect.
Cities can be overheating easily due to the increasing number of heatwaves.
Primarily, the building environment and materials used can cause a temperature difference between urban and rural areas. Secondly, the lack of green areas in the cities can strengthen the UHI effect. Nevertheless, we also have to mention water drainage among the reasons for UHIs.
It is essential to take actions against UHIs at the city level, otherwise, people will continue to use intensively air conditioning which most likely uses electricity produced from fossil fuels, and increases the temperature outside of the flat. In addition, UHIs are harmful for human health, especially for senior citizens and little children.
Naturally, rain cool the temperature efficiently, but due to the quick drainage of rainwater in urban areas, this beneficial effect cannot be exploited.
The best solution for UHI mitigation is developing urban green infrastructure.
Urban climate and heat waves can cause several fatal and non-fatal health issues including heat strokes or dehydration, and they can also decrease labour and learning productivity. Urban green infrastructure can contribute to water retention and help in cooling the city.
We can mitigate UHI effect by/with:
- Planting and taking care of trees
- Green roofs and corridors
- Water retention
- Natural waters
Advantages and challenges
- If streets are shaded, they can be prevented from overheating.
- By planting trees and taking care of the existing vegetation, we can fight against UHIs efficiently and cool the temperature. Increasing the surface of green areas in public places and on buildings (e.g., green roofs and facades) is not only recommended, but rather becoming inevitable.
- Water retention is a priority. Cities and citizens should collect and store rainwater instead of draining it away, and use this natural resource during the dry periods for irrigation or make it possible for plants to absorb it.
- Natural waters like rivers also cool the surroundings. Creating relaxing zones along them, making hot days easier for the citizens.
- UHI has adverse effects on citizens’ health and well-being.
- Although common actions are needed, individuals are also responsible for UHIs. Therefore, awareness-raising, participatory decision-making is required.
- In order to fight against the UHI effect efficiently, cities need climate adaptation action plans as well as commitment and financial sources to implement them.