Why In News?
The Ministry of Housing and Urban Affairs (MoHUA) informs Parliament about efforts to combat the Urban Heat Island (UHI) effect driven by human-induced global warming.
What is the Urban Heat Island (UHI) Effect?
The Urban Heat Island (UHI) effect occurs when urban areas experience higher temperatures than surrounding rural areas due to the replacement of natural land cover with dense, heat-absorbing materials like concrete, asphalt, and metal.
Causes
Low Albedo Materials: Dark surfaces like asphalt absorb and store massive amounts of solar energy instead of reflecting it.
Increased Energy Usage: Air conditioning units cool indoor spaces but exhaust waste heat directly into the outdoor urban atmosphere.
Lack of Vegetation: Deforestation eliminates natural cooling benefits from shade and evapotranspiration.
Urban Canopy: Tall skyscrapers trap heat between buildings, creating multiple layers of thermal reflection.
Wind Blocking: Densely packed buildings block wind flows, reducing natural convective cooling.
Air Pollutants: Vehicular and industrial emissions trap solar radiation in the local atmosphere, acting as a localized greenhouse.
Why is the Urban Heat Island Effect a Major Concern?
Increased Heat Stress: Extreme heat endangers public health, threatening to increase heat-related deaths by one-third by 2050 in cities like Lucknow, Chennai, and Surat.
Higher Energy Demand: Rising urban temperatures increase electricity consumption for cooling, with building cooling demand projected to rise 11 times between 2017-18 and 2037-38.
Poor Air Quality: Elevated cooling demands drive fossil fuel combustion, increasing fine particulate matter and ground-level smog.
Water Stress: Impervious concrete surfaces block rainwater infiltration, depleting groundwater reserves and amplifying local heat.
Climate Change Amplification: The UHI effect intensifies global warming impacts locally, as India's average annual mean temperature rises by 0.64°C per 100 years during 1901-2022.
Labor Productivity Loss: Heat stress reduces physical work capacity, threatening to slash 2% to 4% of urban economic output by 2050.