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Key Findings
Extreme urban heat is becoming an urgent challenge for Bangkok, threatening lives, livelihoods, and the city’s economic resilience. The Urban Heat Island (UHI) effect exacerbates this crisis, turning built-up areas into heat traps that contribute to heat-related mortality, lost productivity, higher energy consumption, and other negative outcomes.
Challenges
The study aims to provide a clear picture of Bangkok’s UHI effect, starting by understanding the magnitude of heat and its locations. Several challenges were identified:
- More days and nights with extreme heat. Between 1960 and 2000, Bangkok experienced 60 to 100 days per year in which temperatures exceeded 35°C. The report’s advanced microclimate modeling forecasts that by the end of 2100, Bangkok could see an additional 153 such days annually under a moderate global emissions scenario.
- Heat island intensity varies across districts. Neighborhoods like Pathum Wan, Bang Rak, Ratchathewi, and Phaya Thai on average are up to 2.8°C warmer than the surrounding countryside as their high-rises and dense concrete surfaces trap and slowly radiate heat.
- Increased heat-related health impacts and premature mortality. Without intervention, a one-degree Celsius rise in Bangkok’s temperature could cause over 2,300 heat-related deaths each year. Vulnerable groups are especially at risk, including about 880,000 children and one million elderly residents over 65 years old — many of whom are concentrated in areas facing the most urban heat.
- Livelihood and productivity losses. In 2019, approximately 1.3 million workers, or about a quarter of Bangkok’s workforce, spend at least one day per week working outdoors. Without intervention, a one-degree Celsius rise in urban temperatures could cause productivity to drop by up to 3.4 percent, causing over 44 billion baht in wage losses each year.
- Strain on infrastructure. A one-degree Celsius rise in temperature could lead to an estimated 17 billion baht in additional electricity costs per year. Extreme heat also affects other infrastructure like roads, necessitating extra repairs and compounding economic impacts.
Strategic Reforms
Although the Bangkok Metropolitan Administration has initiated measures such as its Heat Action Plan, heat-level-based alerts, and greening projects, there remain critical improvement potentials in coverage, cooling resources, and long-term policy commitments. By applying a people (vulnerable groups), places (high-risk areas), and institutions (who coordinate urban heat management) framework, the report suggests:
- Short-term interventions, such as more inclusive heat alerts or systematically opening cooling centers and hydration points in more public locations, could make an immediate difference.
- Long-term policy solutions are also important for setting Bangkok on a path toward greater heat resilience; these could include green and blue infrastructure expansion, as well as integrating climate considerations into urban planning, zoning, transportation, building codes, and public health systems.
- Tackling urban heat requires sustained governance, funding, and multi-sector collaboration. Decision-makers could consider creating a dedicated heat task force to unify different departments, tackle overlapping mandates, work across sectors, and develop robust funding mechanisms (e.g., a dedicated heat resilience fund) to ensure continuity in urban heat reduction initiatives across different administrations.
