The heat island effect is a phenomenon that results in a dome of gathered heat over a certain location. In most cases, this phenomenon only occurs in urban and industrial areas. This effect is very evident because the heat temperature in that affected locations is significantly higher than that of the surrounding rural areas.
It is a well known fact that the population of Earth is exponentially increasing. Along with population increase, rapid technological development is happening as well. Population pressure is a main cause of both direct and indirect environmental impacts. One unknown, but usually neglected, effect is the unmanageable growth of heat islands. The formation of these temperature phenomena is mainly due to the materials used for the constructions of the city buildings. The fast-paced development of cities also considerably contributes to the heat island effects being felt in urban areas.
Heat island effect can intensify intense hot weather proceedings, which can eventually cause heat stroke that could also lead to certain diseases like organ damage, physiological disruption, and even death. –Higher temperatures accelerate chemical reaction which produces smog or the ground-level ozone. This is a big threat to public health, natural environment and in some communities; it will be harder to meet demands for good air quality.
Heat island effect affects climate change in two ways. First, it contributes to the overall global warming. Second, it constitutes a systematic partiality to monitoring of the global thermal surface, because several network thermal sensors are positioned in areas within heat island effects.
Causes of Heat Island Effect
Heat island effects are consistent parts of the modern urban landscape. These are noticed because of the steep temperature difference between that specific area and the cooler surrounding rural locations. The temperature variation can be as high as ten degrees Fahrenheit.
If you have been living in a rural area and working in the nearby urban town, you have surely noticed that big difference between the two locations heat temperature. The most common reason why heat islands happen in urban cities is because of the need to cut down trees and vegetation to make room for the cities. This kind of practice has significantly changed the temperature of the areas, making them a little warmer than locations that have been left untouched by civilization and technology.
Another reason why heat island effect occurs in a specific area is the modern day activities being performed in that location. For instance, if a city is full of industrial plants, it can only be expected that the air will be filled with greenhouse gasses emissions from the factories.
And as mentioned above, the materials used for building construction also contribute to the increase of this phenomenon. Asphalt and concrete, for instance, are construction materials that absorb enormous amounts of heat, which results in increased surface temperatures in the cities.
Tall buildings are also considered as culprits to the heat islands. They often hinder the air circulation in specific areas, which results in wind speed reduction and lessened natural cooling effects.
There are also many city buildings that have been painted with dark surfaces. What most people do not understand is that a dark surface can absorb more heat and light energy than light-colored surfaces. Dark surface are responsible for making the buildings warmer. This is especially true for buildings that have brick roofing and walls that are painted with dark coatings. For buildings with dark surfaces, the heat is transferred inside the building and then radiated back into the air, adding to the dome of heat island effect over the city.
Use of air conditioning is another cause of the heat island effect. When buildings have dark surfaces, they heat up more quickly, thus they entail more cooling from their air conditioning units. This practice will require more use of energy from the power plants, and this will cause more pollution. Air conditioners also exchange heat with the atmospheric air, which will cause additional local heating. Therefore a cascade effect is in evidence and this contributes to the heat island effect expansion.
Other contributors to the heat island effect are the continued use of non-renewable fossil fuels and the expansion of modern day transportation systems. These contribute significantly to the warmer temperature being felt in the urban areas.
How to Reduce Heat island Effect
One way to effectively reduce the heat island effect is to start anew – like going back to the beginning. This means to go green and plant new trees and grow vegetation. Nothing can be a better solution than to really turn back to nature. This should be done now before it is too late. Planting trees is still possible because the Earth is still nurturing all living things. The importance of trees is in the fact that they provide natural shade. They also enhance the overall appeal of the environment. They provide fruits and they help provide fresh air. If there are more trees in the urban areas, it can only be expected that the air moving around will somehow be fresher and cleaner.
Additionally, it has been shown that plants and trees can help in the reduction of the surrounding temperatures through evapotranspiration – it is a process that occurs when water from plants and the ground is released effectively into the air. This process allows the air to form natural humidity, as well as to create a pleasant, cooling effect. On its own, this process has the ability to reduce hot temperature or heat by at least two to nine degrees Fahrenheit.
However, it is not really that simple to solve the issue of the increasing heat island effects. Planting trees is a process that is actually easier said than done, if the areas to be planted to are the cities. Though it is possible for an individual to plant and grow plants and trees in his own backyard, it is not that easy to do the same task in a bigger location.
In order to significantly reduce the impact of the heat phenomenon, it is essential to strategically plant the trees and vegetation in specific areas to black as much of the sun’s heat as possible during the hottest parts of a day. For instance, trees may be planted on the building’s east side to provide it with a shade from the early morning heat from the sun. Planting on the west side is going to provide the building with enough protection from the scorching afternoon sun.
Some experts will even pronounce that there are certain trees that should be used depending on a specific region. For instance, in Greece, in the city of Chania, it has been proven that the Indian laurel fig is the best tree to plant for fighting against the city’s heat and climate change problems. In a research done in this particular city, five trees have been used for comparison. Humidity and temperatures have been measured in shaded and sunny areas. Then the evapotranspiration rate was determined along with measurement of the Discomfort Index – the level of discomfort the heat supplies to the people. It was the Indian laurel fig that has been discovered to have the highest rate of evapotranspiration. The other four trees used for this experiment are; Canary Island date, stone pine, olive tree and the bitter orange. The relatively high humidity under fig trees contribute significantly to a more pleasant and good micro-climate through higher evapotranspiration rates, which is about 6.9 mm in a day – this results in fairly lowered temperatures.
Areas that are planted with different trees are averagely cooler by about 87 degrees Fahrenheit than open and sunlit pavements. Trees and plants are considered to be the most cost-effective means of aiding the decrease in the heat temperatures being experienced in the urban areas. This is cheaper than installing cooling fans and sun awnings.
Aside from reducing the heat island effect, the use of greenery offers other positive benefits. With trees that surround buildings provide shade that will minimize the need for use of air conditioning. This results in less need for energy to keep these areas cool during the hottest days. Air quality is always better when there are trees around because plants have the ability to effectively store enough carbon dioxide. Green vegetation also reduces greenhouse gases emissions. Lastly, plants and trees make the areas better looking.
Heat island effect refers to city air and urban surface temperatures that are comparatively higher than those in the nearby rural locations. Many suburbs and cities have air temperatures that are up to two to ten degrees Fahrenheit warmer than neighboring rural areas. Elevated environment temperatures can significantly impact communities in a lot of ways; by increasing demands for energy use, increasing costs for air conditioning, increasing pollution levels, and increasing illnesses and mortality.
Different solutions have been put forward for the effective reduction of heat island effect in urban areas. It is up to the communities and local governments to either follow or ignore the proposed solutions. The choices include: planting more trees and plants; painting building surfaces with white; use of sustainable energy resources; and decreased use of air conditioning systems.