Urban warming: causes and solutions
What is meant by excessive warming in the cities? The so-called heat islands in urban residential areas, caused by the formation of a microclimate which is warmer compared to temperatures in the suburbs or rural areas have in fact been documented since the nineteenth century.
Among the main causes of this phenomenon are, first of all, factors such as tree felling, the construction of large buildings, emissions from engine exhausts and the covering of waterways.
In addition, the dark coloured materials used for road surfaces and rooves increase the temperature by as much as 7 degrees Celsius. Buildings also obstruct the free circulation of air and thereby contribute further to the increase in heat.
The most absurd thing is that in order to deal with the higher temperatures, people tend to misuse air-conditioning systems, thereby producing even more heat and consuming large amounts of power, which in turn generates even more emissions.
However, heat islands are not only present in urban residential areas at ground level, but also in the atmosphere: the temperature at ground level reaches a peak in the late afternoon, while the temperature of the atmosphere reaches its highest point at night.
One example which illustrates the phenomenon of increased heat in cities is the city of Baltimore, USA, which lies down-wind from Washington: this geographical feature prevents a normal circulation of wind there, resulting in a rise in temperature of several degrees.
Considering that heat islands have drastic effects on the global climate, what measures should be adopted to deal with this problem? The main ones include:
- Making an effort to conserve as many trees as possible (they provide shade, maintain humidity, absorb and release water, thereby cooling the environment);
- Choosing paving with tiles with holes for the grass to grow through (this solution repels light and stores rain water);
- More roof gardens (which cool buildings and produce oxygen).
This is a brief overview of the issue of heat islands: a phenomenon capable of causing significant environmental problems, but which can be reduced by adopting some targeted strategies.
Translated by Joanne Beckwith
