Syllabus: 

GS 1: Important Geophysical phenomena and geographical features 

Context: 

Recently, a new study in Nature Climate Change highlighted that Urban heat islands reduce cold-related deaths more than they increase heat-related deaths.

Urban Heat Island (UHI) Effect

• UHI is a metropolitan area that's a lot warmer than the rural areas surrounding it. Heat is created by energy from all the people, cars, buses and trains in big cities like New York, Paris, and London.
• This effect can increase heat-related deaths but may also reduce deaths related to cold exposure. 

Key Findings from Nature Climate Change Study

• The UHI effect may offset some heat-related mortality by reducing cold-related deaths in some global cities.
• In 2018, the reduction in cold-related deaths due to the UHI effect was 4.4 times greater than the increase in heat-related deaths.
• In high-latitude cities like Moscow, the reduction in cold-related mortality was 11.5 times greater than the increase in heat-related mortality.

Methodology

• Study led by scholars of Nanjing University in China.
• They used a combination of remote sensing data, climate variables and socioeconomic indicators (e.g., GDP) to establish mortality-temperature relationships across more than 3,000 cities worldwide.

Common UHI Mitigation Strategies:

• Increasing vegetation: Increasing vegetation cover through tree planting, parks, green roofs, and other green spaces can absorb heat.
• Enhancing the albedo (fraction of light that a surface reflects)
• Optimizing Urban Geometry: Strategic urban planning, including building orientation and spacing can influence airflow and reduce heat accumulation. 
• Cooling Systems: Misting systems, water walls and other water-based cooling systems can create microclimates that provide relief from heat stress.
• These strategies may increase cold-related deaths in some cases outweighing reductions in heat-related mortality, depending on their scale and the season of implementation.

UPSC Mains PYQ

Bring out the causes for the formation of heat islands in the urban habitat of the world. (2013)

UPSC Mains practice-based question

Q. The Urban Heat Island (UHI) effect, while contributing to heat-related mortality, may also reduce cold-related deaths in certain regions. Critically examine this dual impact in the context of urban planning and climate change mitigation strategies.