Urban Heat Island

In Context

• Urban heat islands escalate the warming of weather.

About

• Urban heat islands (UHI) occur when cities replace the natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat.
• This effect increases energy costs associated with cooling and air-conditioning, air pollution levels, and heat-related illness and mortality.

 What are the causes of Urban Heat Island?

• Usage of too much concrete and cement in a limited space: They absorb a lot of heat from the sun thus increasing the mean surface temperatures of pockets in urban areas.
• Dark surfaces: Buildings with dark surfaces reduces the albedo and increase heat absorption.
• Air conditioning and other cooling systems: Cooling required from air conditioning consumes a great amount of energy from power plants thus causing more pollution. The air conditioners emit hot air which further causes more heat thereby having a cascading effect.
• Concretised urban Landscapes: A large number of concrete buildings with cemented pavements around hinder the wind flow hence reducing any natural cooling effects.
• Massive transportation system: Transportation systems in the cities produce a great amount of heat because of fossil fuel burning which is beyond the carrying capacities of incoming cool winds.
• Paucity of Tree covers: This prevents evaporation and transpiration, shade and removal of carbon dioxide, all the processes that help to cool the surrounding air.

Impact of UHI

• Increases Energy costs: UHI effect increases energy costs, air pollution levels and heat-related illness. This also leads to global warming, which further contributes to climate change.
• Bad air quality: They lead to lower air quality as there is more pollution in UHIs as a result of increased fossil fuel consumption.
• Poor water quality: The pollution in the region makes water bodies polluted.
• Heatwaves: Cities with UHIs face heat waves that affect human and animal health which affects the general physiology of the organisms.

Ways to prevent Urban Heat Island effect

• Green roofs: By covering the roofs of the buildings with plants can help in cooling the building.
• Keeping the colours of building light: helps in less absorption of heat by increased albedo and less heat retention.
• Having more tree cover: They reduces the number of greenhouse gasses in the region and increases the evaporation and transpiration thus keeping the region cool. They also keep the surroundings cooler thereby decreasing the cost of air-conditioning.
• Adhering to environmentally sustainable solutions like Green Building Code which makes the building more eco-friendly.

 Source: DTE