Analyzing Asia's greenest and least green metropolises | DW News

Key Concepts:

• Urban tree cover: The extent of greenery within a city.
• Urban heat island effect: The phenomenon where urban areas experience higher temperatures than surrounding rural areas.
• Nature-based solutions: Approaches that use natural systems to address environmental challenges.
• Blue-green infrastructure: A network of natural and semi-natural elements designed to provide ecological and hydrological services.
• Informal sector: The part of an economy that is neither taxed nor monitored by a government.
• Transpiration rate: The rate at which water is lost from a plant through evaporation.
• Stomata: Pores on plant leaves that allow for gas exchange and transpiration.

Analysis of Tree Cover in Asian Cities

• Overview: DW analyzed tree cover in 50 major Asian cities to determine the proportion of residents living in areas with lush or sparse greenery.
• Findings: Significant variation exists in tree cover across Asian metropolises.
• Cities with High Tree Cover: Only four cities were identified where most residents live in areas with abundant greenery: Colombo (Sri Lanka), Mumbai (India), Yangon (Myanmar), and Chongqing (China).
  • Colombo: Almost 40% of residents live near many trees. The city benefits from large green spaces like Viharamahadevi Park and proximity to natural green areas. However, lush zones are primarily in the suburbs, while the densely populated city center has sparse tree cover, especially near the Colombo Port City. Coastal roads with high-rise buildings lack space for trees due to the high economic value of both horizontal and vertical space.
• Cities with Low Tree Cover: Many cities have a majority of residents living in areas with minimal tree cover. These include Riyadh, Karachi, Kabul, Tokyo, and Dhaka.
  • Karachi: 80% of residents have very little tree coverage near their homes. The city is located in a desert region with limited natural tree cover and historically little plantation. However, efforts are underway to create urban forests, such as on hilltops, using recycled water for irrigation.

Impact of Tree Cover on Climate and Economy

• Heatwaves: South and Southeast Asia are experiencing extreme heat levels, with dozens of deaths reported in Thailand and record-high temperatures in Delhi (52.3 degrees Celsius).
• Urban Heat Island Effect: Trees can mitigate the urban heat island effect through shade and high transpiration rates, providing thermal comfort.
• Economic Implications: Lack of shade impacts informal sector workers (over 80% of India's workforce), leading to mortality, illness, reduced productivity, and loss of livelihoods. This has implications at individual, city, and national economic levels, affecting GDP.

Factors Influencing Tree Cover

• Climate, Terrain, and Biome: Tropical climates favor more green spaces, while desert regions typically have sparse tree cover.
• Geography: Cities in similar climates can have different tree coverage levels, as seen in the comparison between Manila (Philippines) and Yangon (Myanmar).

Strategies for Increasing Urban Tree Cover

• Singapore as a Model: Singapore is highlighted as a successful example of integrating nature into a densely populated urban environment.
  • Nature-Based Solutions: Singapore uses nature-based solutions to integrate green spaces into developmental areas.
  • Vertical Greening: Vertical gardens and green walls are implemented along vertical spaces.
  • Green Corridors: Networks of parks and green corridors are preserved.
  • Blue-Green Infrastructure: Singapore effectively integrates blue-green infrastructure with grey infrastructure.

Conclusion:

The analysis reveals significant disparities in tree cover across Asian cities, impacting climate, public health, and economic productivity. While geographical factors play a role, strategic urban planning and nature-based solutions, as exemplified by Singapore, can significantly enhance tree cover and mitigate the adverse effects of urbanization and climate change. The need for increased tree cover is particularly acute in cities like Karachi, where proactive measures such as urban forest creation and recycled water usage are essential.