Daily Hot Topic
Monitoring of Urban Heat Islands
GS-1 Mains : Geography
Revision Notes
Question : Define the concept of urban heat islands (UHIs) and analyze the factors responsible for their formation. Propose solutions and strategies to mitigate the impact of UHIs
- Role of Technology: Providing data-driven insights to understand the nature and intensity of heat stress in urban heat islands.
- Tech Innovations for Monitoring in India:
- Remote Sensing Satellites: Offer data for tracking weather patterns, land surface temperatures, and urban heat islands.
- Hard Infrastructure Sensors: Deployed in cities to collect real-time data on various parameters like temperature, humidity, precipitation, and air quality.
- Challenges: India’s tech adoption in weather and heat risk monitoring is improving but lags behind developed countries.
- Leading Indian cities have an average of 7-8 India Meteorological Department (IMD) weather stations, compared to over 100 in a similar city like San Francisco.
- Data: India focuses more on water risk and security, leading to more granular data on precipitation. Heat isn’t a consistent part of the monitoring process.
- Developed economies have weather tracking done by diverse actors – academia, research institutions, government bodies, and the private sector. This rich data provides a nuanced understanding.
- What is an Urban Heat Island (UHI)? A UHI is an area with higher temperatures than surrounding rural areas due to human activities and infrastructure.
- International Organization for Migration (IOM): Urban heat islands can lead to temperature differences of up to six degrees celsius within a specific area or neighborhood.
- Factors Responsible for Urban Heat Islands:
- Built Environment: Materials used in urban construction, like concrete and asphalt, absorb and retain heat, raising local temperatures.
- Reduced Vegetation: Urban areas typically have fewer trees and green spaces compared to rural areas, reducing the cooling effect of shade and transpiration.
- Human Activities: Activities like transportation, industry, and energy consumption release heat into the environment, further elevating temperatures.
- Altered Surface Characteristics: Urbanization often involves replacing natural surfaces with artificial ones, which alters surface reflectivity (albedo) and thermal properties, contributing to increased heat absorption.
- Ecological Factors: According to a 2014 Indian Institute of Science report, the ideal tree-to-human ratio is seven trees per person. Lack of trees increases the risk of exposure to higher temperatures.
- Some Indian cities have as few as one tree for every 50 people.
- Lack of water bodies can also add to the heat effect.
Concerns
- Health Risks: Higher temperatures in cities lead to heat-related illnesses like heatstroke and exhaustion, especially for vulnerable groups like children, the elderly, and those with pre-existing conditions.
- Energy Consumption: Increased demand for cooling due to higher urban temperatures raises energy use and greenhouse gas emissions.
- Water Management: UHIs disrupt local water cycles, changing evaporation rates and reducing groundwater recharge.
- Social Inequity: Low-income communities and people in inadequate housing are disproportionately affected by UHIs due to limited access to cooling and healthcare.
Solutions
- Increase Vegetation: Planting trees and creating green spaces provide shade and evaporative cooling, reducing the UHI effect.
- Cool Roofs: Using reflective materials on roofs minimizes heat absorption and lowers surface temperatures. White or reflective roofs significantly reduce heat buildings absorb.
- Urban Planning & Design: Integrating UHI mitigation strategies into urban planning creates cooler, more livable cities.
- This includes wider sidewalks, shade structures, and strategic building placement for optimal shade and airflow.
- Water Bodies & Fountains: Incorporating ponds, lakes, and fountains into urban areas cools the environment through evaporation and creates microclimates.
- Community Engagement & Education: Educating residents about UHIs and mitigation methods fosters involvement in UHI reduction efforts.
The Way Ahead
- Technology plays a crucial role in providing data-driven insights on heat stress, enabling early warnings and exploring new “cooler” materials for mitigation.
- However, UHI is primarily an urban design and development issue requiring a broader approach encompassing economic policy, city management, and promoting sustainable urban living.
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