Urban Heat Island Effect and Nighttime Heat Stress in Hyderabad

Why in the News ?

The Telangana Socio-Economic Outlook 2025 has raised concerns over increasing nighttime heat stress in Hyderabad due to the Urban Heat Island (UHI) effect. The city is experiencing significantly higher nighttime temperatures than its rural surroundings due to rapid urbanization and infrastructure growth.

Causes of the Urban Heat Island Effect:

  • Urbanization replaces natural landscapes with heat-absorbing materials like concrete and asphalt.
  • Lack of vegetation reduces natural cooling, increasing overall temperatures.
  • Heat emissions from vehicles, air conditioning, and industries contribute to rising urban temperatures.
  • Tall buildings and narrow streets create urban canyons, trapping heat and restricting air circulation.
  • The heat absorbed during the day is released at night, preventing cooling and intensifying heat stress.

Impact on Hyderabad

  • Higher nighttime temperatures make sleeping conditions uncomfortable, especially in summer.
  • Temperature differences of up to 12°C have been observed between urban and rural areas.
  • Increased energy demand for cooling leads to higher electricity consumption and costs.
  • Worsening public health risks, such as heat strokes and respiratory issues.
  • Environmental degradation due to excessive heat stress and lack of sustainable cooling solutions.

Possible Solutions

  • Expanding green cover through urban forests, rooftop gardens, and tree plantations.
  • Using reflective and heat-resistant building materials to minimize heat absorption.
  • Improving urban planning with wider streets, better ventilation, and open spaces.
  • Encouraging sustainable cooling solutions like energy-efficient buildings and cool roofs.
  • Public awareness and policy interventions to mitigate long-term climate impact.

Urban Heat Island (UHI) Effect: Key Points

●Definition: UHI is a climatic phenomenon where urban areas experience significantly higher temperatures than surrounding rural areas.

●Causes:

○  Loss of green spaces reduces shading and evapotranspiration, limiting natural cooling.

○ Concrete and asphalt structures absorb and retain heat, increasing temperatures.

○ Narrow streets and tall buildings create urban canyons, restricting airflow.

○ Heat emissions from vehicles, industries, and air conditioning add to warming.

● Impact:

○ Urban microclimates develop, intensifying heat stress and discomfort.

○ Nighttime temperature differences can reach up to 12°C, preventing cooling.

● Visual Representation: Urban areas appear as “heat islands” in temperature maps.