Monitoring of Urban Heat Islands

General Studies Paper-3

Context: The role of tech is in providing data-driven insights into the nature and intensity of heat stress in urban heat islands.

Tech Innovations for Monitoring Weather and Heat Risks

• In India, several tech innovations have enhanced weather and heat risk monitoring.
  • There is the soft infrastructure of remote sensing satellites which provide data for tracking weather patterns, land surface temperatures and urban heat islands.
  • Hard infrastructure sensors are deployed in cities to gather real-time data on several parameters like temperature, humidity, precipitation and air quality.
• Challenges: India’s tech adoption in weather and heat risk monitoring is improving but is not at par with other developed countries.
  • The leading Indian cities have seven to eight India Meteorological Development weather stations on an average, a comparable city like San Francisco would have more than 100 weather monitoring stations.
  • Data: India focuses more on water risk and security and hence have more granular data on precipitation, while heat is not a consistent part of the monitoring process.
    • In developed economies, weather tracking is done by a variety of actors, from academic and research institutions to government bodies to the private sector. All of this rich data provides a much more nuanced understanding of scenarios.

What is an Urban Heat Island?

• An Urban Heat Island (UHI) is an area in which the temperature is higher than in surrounding rural areas due to human activities and infrastructure.

International Organization for Migration (IOM)

• Urban heat islands could lead to temperature differences of up to six degrees centigrade within a given area or neighbourhood.
• Urban heat islands result from complex interactions between built environments, natural factors, and human activities.

Factors Responsible for Urban Heat Islands

• Built Environment: The materials used in urban construction, such as 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, which reduces 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 the 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-human ratio should be seven trees for every person. The lack of trees increases the risk of exposure to higher temperatures.
  • In Indian cities there are places with such poor density of trees as one tree for 50 people.
  • Also the lack of water bodies can add to the heat effect.

Concerns

• Health Risks: Elevated temperatures in urban areas lead to heat-related illnesses such as heat exhaustion and heatstroke, particularly among vulnerable populations like the elderly, children, and individuals with pre-existing health conditions.
• Energy Consumption: Higher temperatures in urban areas lead to increased demand for cooling, which escalates energy consumption and associated greenhouse gas emissions.
• Water Management: UHIs disrupt local water cycles by altering evaporation rates and reducing groundwater recharge.
• Social Inequity: Vulnerable populations, including low-income communities and people living in inadequate housing, are often disproportionately affected by UHIs due to limited access to cooling resources and healthcare services.

Suggestions

• Increasing Vegetation: Planting trees and creating green spaces can help reduce the urban heat island effect by providing shade and evaporative cooling.
• Cool Roofs: Using materials with high solar reflectance on roofs can reduce heat absorption and lower surface temperatures. White or reflective roofing materials can significantly decrease the amount of heat absorbed by buildings.
• Urban Planning and Design: Incorporating UHI mitigation strategies into urban planning and design can help create cooler and more livable cities.
  • This includes designing streetscapes with wider sidewalks, shade structures, and strategic placement of buildings to maximize shade and airflow.
• Water Bodies and Fountains: Incorporating water bodies such as ponds, lakes, and fountains into urban areas can help cool the surrounding environment through evaporative cooling and creating microclimates.
• Community Engagement and Education: Educating residents about the urban heat island effect and ways to mitigate it can foster community involvement in UHI reduction efforts.

Way Ahead

• The role of tech is in providing data-driven insights into the nature and intensity of heat stress, providing early warning, and at the mitigation end look at the larger gamut of materials and coming up with ‘cooler’ materials.

But more importantly, the urban heat islands issue is an urban design and development issue, which needs to be looked at from a bigger lens of economic policy, city management and sustainable living in cities.