Have you ever noticed that cities often feel noticeably hotter than rural places? That is no coincidence! This is a phenomenon called the Urban Heat Island Effect. Although it typically only raises the temperature in the city by a few degrees, those few degrees can have long-lasting and significant impacts on the health of the urban population and the surrounding environment. Such impacts include health hazards, increased energy consumption, and even decreased air quality.
In the summer, when the Urban Heat Island Effect is most prevalent in cities, people tend to turn their air conditioning on maximum power, which leads to increased energy consumption. Consequently, more fossil fuels are used to cool homes, which subtracts from air quality. Finally, a bubble called a temperature inversion forms over the city, trapping smog inside. These effects compound with each other and create a vicious cycle that makes the urban environment harsher.
Since we know that the Urban Heat Island Effect has multiple negative impacts, we should reflect on what causes it in order to explain how it can be dealt with. The first major factor that causes the Urban Heat Island Effect is heat that comes out of our machines and cars. This cause is straightforward: the heat byproduct from our creations leak out into the environment. The second, more obscure major factor that causes the heating is the replacement of natural surfaces with dark and impermeable surfaces. Vegetation has a natural cooling effect because it provides shade and allows for evaporation, so when vegetation gets torn down the temperature tends to rise. Additionally, the dark, manmade surfaces that we use to replace vegetation absorb more heat and don’t allow water to percolate down into the ground, instead being redirected to storm drains. Without the water on the surface, there is no evaporative cooling, which makes cities even hotter.
What can we do to alleviate the heat? One common solution that is being explored is to add more vegetation to the urban environment, sometimes even on a roof or terrace. This way, the evaporative cooling from plants can be used to cool down the surrounding environment. Another more zealous solution is to create permeable and reflective parking lots and sidewalks to have them absorb less heat and, therefore, have more water for evaporation to occur. Of course, these solutions are up to city planners to create and implement, so it may seem hard to have an individual impact. However, there are small ways to help that anyone can do. Things such as using less energy, carpooling, and planting vegetation can help decrease the severity of the heat. It’s important to keep in mind that what we change about the environment will come back to us in the end such as in the case of the Urban Heat Island Effect, so thinking about how we change our world will always be essential to our prosperity.
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© 2019 Weather Forecaster Cole Bristow