Architects must mitigate GCC's urban heat islands
As GCC governments lead the discussion about climate change in the Middle East, architects and designers can make a difference by mitigating urban heat islands
Urban heat islands are best described as the temperature gradient difference between developed and undeveloped areas. This temperature discrepancy induces an upsurge in the air and surface temperatures. The elevation has a deep impact on the physical and chemical properties of the atmosphere.
Such islands are mostly common in highly populated and densely constructed urban communities. In addition to altering the environment, heat islands are considered to be the main factor in increasing air cooling costs, air pollution levels, energy demand, and heat-related illnesses.
Even if the temperature disparity is minor, heat islands could pose a threat by forming heat waves within urban areas. An attempt to diminish these islands would minimise their adverse outcome on microclimates, and human, wildlife, and aquatic habitats.
Compared to urban communities, rural areas are less affected by the heat islands. During daytime, natural surfaces composed of vegetation and soil absorb a large portion of sunlight. This absorption causes the release of water in moisture-trapping soils – a process called evapotranspiration, during which evaporated air cools the surrounding atmosphere. The other fraction of incident radiation from sunlight is reflected as heat.
In cities, most exteriors are man-made surfaces formed from non-reflective and water-resistant material. Large areas covered with cement have a low solar reflectance index (SRI), and they absorb the solar rays.
Moreover, non-porous surfaces, such as asphalt, tar, and concrete possess high thermal conductivity properties. These surfaces block the absorption of rain water and form hefty heat conductors.
Waste heat from buildings, sidewalks, parking lots, and roads is another factor that contributes to the heat island effect. Energy dissipation from cars, people, and concrete buildings constitutes a great portion of thermal inclination.
Modern construction design has focused on creating highly insulated building models, which can prohibit the transfer of external heat to the structure. This method has created a warmer envelope around the buildings.
Furthermore, air quality is also affected, as industry and vehicular pollutants are trapped in the warm air. These pollutants are contained within the urban landscape, and are unable to scatter.
Heat islands intensify during summers, thus increasing the need for air-conditioning. This in turn increases the need for energy production and electricity. Global warming is also directly affected by this phenomenon.
Architects and designers are responsible for the mitigation of heat islands. Through sustainable designs and modern urban planning, they can reduce the impact of the heat islands and keep cities cooler.
Decision makers must adhere to ‘green’ practices and sustainable standards by choosing building material with a high SRI. Environmental policies and programmes must also stress on reducing the impact of heat islands in urban communities.