Urban Climate Stress and Rising Weather Anomalies in India

GS 3 – ENVIRONMENT

Context:

The first half of 2025 has seen a series of weather anomalies across India, highlighting the deepening impacts of climate change on urban environments, marked by abnormal temperatures, erratic rainfall, elevated humidity, and increasing urban fragility.

Rising Humidity: Key Drivers

• Warming Oceans: Elevated sea surface temperatures enhance evaporation rates, increasing atmospheric moisture.
• Frequent Low-Pressure Zones: More depressions over the Bay of Bengal push moist air further inland.
• Urban Surface Sealing: Extensive use of impervious materials like concrete limits natural evaporation.
• Declining Urban Greenery: Reduction in trees and green spaces cuts down transpiration-based cooling.
• Monsoon Irregularities: Delayed and inconsistent rainfall leads to prolonged pre-monsoon humidity spells.

Urban Areas: Epicenters of Climate Vulnerability

• Dense Populations: Urban crowding amplifies disaster risks and complicates relief efforts.
• Heat-Trapping Materials: Asphalt and concrete retain daytime heat, worsening urban temperatures.
• Inadequate Drainage: Poorly planned infrastructure leads to urban flooding after minimal rainfall.
• Urban Canyon Effect: Closely spaced tall buildings hinder airflow and trap heat.

Understanding the Urban Heat Island (UHI) Effect

Urban Heat Island is a localized warming phenomenon where parts of a city experience significantly higher temperatures than nearby rural or open areas due to:

• Thermal Retention: Buildings and roads absorb heat during the day and release it slowly at night.
• Anthropogenic Heat Sources: Emissions from vehicles, air conditioners, and industries add to the heat burden.
• Airflow Obstruction: Skyscrapers restrict wind movement, intensifying radiant heat retention.
• Pollution Haze: A layer of pollutants traps heat, raising night-time temperatures.

Compounding Impact of Humidity

• Economic Losses: Heat-related damages cost the global economy approximately US$624 billion annually.
• Employment Challenges: An estimated 34 million jobs could be impacted in the next five years (World Bank).
• Labour Productivity Decline: From 2001 to 2020, heat stress caused the loss of 259 billion work hours annually.
• Health Risks: Excess humidity hampers sweating, leading to heat exhaustion, dehydration, and sleep disorders.
• Lightning Fatalities: Enhanced convection due to humidity has increased lightning strikes — over 150 deaths reported in Bihar in March–April 2025.
• Post-Harvest Losses: High humidity causes spoilage of perishables and reduces shelf life of crops, affecting commodities like wheat, rice, and sugarcane.
• Energy Burden: Humidity worsens the UHI effect, pushing up electricity demand and overloading power infrastructure.

Strategies for Building Urban Climate Resilience

Structural Approaches

• Infrastructure Audits: Conduct periodic reviews to identify vulnerabilities in urban infrastructure and upgrade accordingly.
• Decentralized Energy Systems: Promote solar rooftops, microgrids, and biogas units to maintain energy security during climate disruptions.
• Climate-Resilient Housing: Update building codes to include cool roofing, passive ventilation, and retrofitting support for vulnerable localities.
  • Example: Hyderabad’s cool roof initiative serves as a replicable model.
• Coastal Urban Planning: Modify coastal architecture with raised foundations, mangrove buffers, and adaptive zoning laws.

Non-Structural Measures

• Advanced Alerts: Use AI-driven forecasting systems and community apps for real-time updates on extreme weather events.
• Climate-Focused Budgeting: Integrate resilience metrics into municipal budgeting and planning processes.
• Dedicated Resilience Units: Set up Urban Climate Resilience Cells at the local and state levels to streamline policy, data management, and emergency coordination.

Global Best Practices in Urban Climate Adaptation

City	Initiative
Paris	Mandatory green roofs or solar panels on new commercial structures
Singapore	Vertical gardens and rooftop parks to mitigate urban heat
Netherlands	Parks designed to act as stormwater retention zones
Tokyo	Green Credit System incentivizing private developers to create green space
New York	Climate-resilient infrastructure standards for future-proofing
Copenhagen	Integrated blue–green stormwater systems to prevent flooding