Last Updated on April 29, 2024 by HBW2
An urban heat island refers to a phenomenon where cities experience higher air temperatures than the surrounding countryside. Here are some key points about urban heat islands:
Causes of Urban Heat Islands:
As cities grow, new development such as roads and buildings displace natural surfaces like trees, ponds, and soil. These natural surfaces help moderate air temperatures by providing shade and cooling through processes like “evaporative cooling.”
However, man-made surfaces (such as asphalt roads and concrete buildings) tend to absorb and re-emit more heat, contributing to higher temperatures in cities.
Human activities like power generation, car use, and air conditioning also add to the heat load.
The geometry of cities, including narrow spaces between tall structures (known as urban canyons), can trap heat.
Health Risks and Environmental Impact
Urban heat islands pose significant health risks, including heat stroke, heat exhaustion, and heart attacks. Vulnerable communities, such as low-income and minority populations, are often disproportionately affected.
Higher temperatures lead to increased energy consumption (from cars and buildings), worsening air pollution and contributing to climate change.
Top 5 hottest cities in India:
Mungeshpur, Delhi: Recorded a maximum temperature of 49.2°C
Najafgarh, Delhi: Reached 49.1°C
Banda, Uttar Pradesh: Experienced 49.0°C
Gurugram, Haryana: Reported a high of 48.1°C
Churu, Rajasthan: Reached 47.9°
Mitigation Strategies:
Reintroducing vegetation is crucial. Cities can expand parkland, plant street trees, and install “green roofs” that harbor plant life. Vegetation can lower nearby air temperatures by around 4°F.
Cool roofs and pavements with reflective coatings can also help reduce heat absorption.