At Heat Islands they are a climatic and urban phenomenon, that is, they happen in the atmosphere of cities, and consist of a very intense increase in temperatures in more urbanized spaces. In some cases, some points in the cities even register an increase of 7ºC or more in relation to the more remote areas.
When walking through streets surrounded by buildings, cars, asphalt and with few trees, we quickly feel a sensation of discomfort caused by the heat on our skin, right? This is exactly what happens with heat islands. We will list below the various factors that contribute to this phenomenon:
1) Absence of trees: Vegetation contributes to increasing air humidity and decreasing ambient temperatures, so that when humans remove them for the construction of houses, streets and buildings, the environment becomes more hot.
2) Greater heat absorption: In cities, the construction of buildings, sidewalks, houses and, above all, asphalt absorb more heat than “clean” earth, which contributes to the rise in temperature.
3) Less infiltration of soils: With urban constructions, virtually all the soil is covered with concrete and asphalt, making it difficult to build up and infiltration of water, thus reducing the level of evaporation which would have the function of controlling the temperature.
4) Building construction: A lot of buildings in a small space makes the air flow more difficult, forming real "walls" along the streets, preventing that cooler wind from circulating normally.
Buildings impede air circulation and reflect heat back to the street
5) Pollution: The large amount of pollutants emitted by cars, factories, homes and others is responsible for retention solar radiation, intensifying the greenhouse effect and further contributing to the increase in heat in the city.
Urban pollution contributes to making cities warmer
When the Heat Islands phenomenon is associated with other urban problems, such as Thermal Inversion, the life in some geographic spaces becomes very difficult as the temperature conditions become unsustainable. For this reason, governments and city dwellers need to act together, reducing pollution and deforestation in cities, in addition to better planning social actions to make the environment more pleasant for all.
By Rodolfo Alves Pena
Graduated in Geography
