GS Paper - 1 (Geography)

Several parts of the country are reeling under heat wave conditions. Cities, especially, are a lot hotter than rural areas. This is due to a phenomenon called an “urban heat island”.

What is an urban heat island?

  1. An urban heat island is a local and temporary phenomenon experienced when certain pockets within a city experience higher heat load than surrounding or neighbouring areas on the same day.
  2. For example, a greener locality like Pashan in Pune often records cooler temperatures than urban areas like Shivajinagar, Chinchwad or Magarpatta.
  3. The variations are mainly due to heat remaining trapped within locations that often resemble concrete jungles. The temperature variation can range between 3 to 5 degrees Celsius.
  4. Rural areas have relatively larger green cover in the form of plantations, farmlands, forests and trees as compared to urban spaces. This green cover plays a major role in regulating heat in its surroundings.
  5. Transpiration is a natural way of heat regulation. This is the scientific process of roots absorbing water from the soil, storing it in the leaves and stems of plants, before processing it and releasing it in the form of water vapour.
  6. On the contrary, urban areas lack sufficient green cover or gardens and are often developed with highrise buildings, roads, parking spaces, pavements and transit routes for public transport. As a result, heat regulation is either completely absent or man-made.