Q16. शहरी उष्मा द्वीप (UHI) भारतीय शहरों में एक चिंताजनक घटना है, जो गर्मी की लहरों की आवृत्ति और तीव्रता में योगदान दे रही है। इस घटना के अंतर्निहित कारणों का विश्लेषण करें और वर्तमान में मौजूद शमन रणनीतियों का आलोचनात्मक मूल्यांकन करें। (15 अंक) Urban heat islands (UHIs) have become a significant phenomenon in Indian cities, exacerbating the frequency and intensity of heat waves. Analyze the underlying factors contributing to this phenomenon and critically assess the existing mitigation strategies. (15 marks)

Urban Heat Islands refers to phenomenon in which urban areas are hotter in temperature than their surrounding areas.

To Tu

[Diagram showing heat island effect with buildings and surrounding areas, labeled: Ts < Tu with notation "concreted roads and pavement"]

This has led to:

Impacts:

Underlying factors contributing to UHI:

(i) Concretisation of areas — roads, pavements, open areas.

(ii) Reduction in trees and green spaces like parks that absorb heat.

(iii) Tall structures that increasing surface area for heat absorption.

(iv) Greater heat retention of the concrete areas.

v) Increasing temperature due to global warming. (eg) UNEP - over 1.2°c rise already.

vi) Increased no. of days of sunshine and lower rainfall — changing weather patterns due to climate change.

vii) Exhaust emissions from cars — trapping heat in the cities.

viii) Policy failure to address heat island effect.

ix) Lesion of heat dome.

[Simple diagram showing heat dome rising air pushed back down]

Existing mitigation strategies:

i) Heat Action Plan — increasing shade, healthcare facilities, water.

ii) Reducing climate change effects - adaptation (eg) Coalition for Disaster Resilient Infrastructure (CDRI)

iii) Reclamation of green spaces. (eg) Rooftop Parks

iv) Protection of wetland (eg) Ramsar convention

Limitations in current strategies:

Further strategies to be adopted:

Urban heat wave mitigation require strategic and sustainable development of cities as enshrined in SDG 11.