Rapid Fire
Green Paradox in Urban Greening
- 06 Jan 2026
- 2 min read
A global study covering 761 cities across 105 countries, including India, shows that urban greening does not always cool cities and that poorly planned tree and vegetation planting can worsen heat, particularly in dry and water-scarce regions.
- Urban Heat Drivers: Cities are heating up due to global climate change and the urban heat island effec, where concrete and asphalt trap more heat than surrounding rural areas.
- Temperature Regulation Capability: The study used a metric called Temperature Regulation Capability, defined as the temperature difference between vegetated surfaces and built-up surfaces such as concrete and asphalt.
- A negative value indicates that vegetation is cooler than built-up areas (cooling effect), while a positive value indicates that vegetation is warmer (warming effect), helping the study assess when and where urban greening reduces or intensifies city heat.
- Study Findings: Overall, vegetation cooled most cities, but nearly one-fourth of cities, mainly with low rainfall (<1,000 mm), experienced net warming instead.
- Green Paradox in Dry Regions: In arid and semi-arid cities, limited water availability weakens evapotranspiration (release of water vapour), reducing the cooling effect of vegetation.
- At the same time, vegetation can absorb more solar radiation than some built surfaces, which can increase surface temperatures.
- During heat stress and low humidity, plants further restrict water loss, sharply cutting evaporative cooling and intensifying urban heat.
- This is crucial for India, where many cities require climate-appropriate vegetation and integrated heat-mitigation planning.
| Read more: Urban Heat Island Effect |
