Taking on Bangkok's punishing heat
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Taking on Bangkok's punishing heat

Tourists walk along a pavement next to the Temple of the Emerald Buddha, or Wat Phra Kaeo, on Na Phra Lan Road, in the hot sunshine, on April 25, 2024. (Photo: Apichart Jinakul)
Tourists walk along a pavement next to the Temple of the Emerald Buddha, or Wat Phra Kaeo, on Na Phra Lan Road, in the hot sunshine, on April 25, 2024. (Photo: Apichart Jinakul)

As scorching temperatures blanket Thailand, setting new records in several regions, Bangkok and its outskirts are enduring the full force of the relentless heatwave. Bangkok sizzled under a heat index exceeding 52C on Tuesday, a measure that combines temperature and humidity to reflect how hot it actually feels. Tragically, heat-related fatalities in the country have reached 30 this year alone. A recent study reveals the unequal impact of urban heat intensity on Bangkok's residents, with lower-income individuals facing heightened heat stress during daily activities and rest.

The recent surge in temperatures in Bangkok is linked to global temperatures rising by approximately 1.1C since pre-industrial times, largely due to climate change. This year, Asia, particularly Southeast Asia, has experienced an alarming increase surpassing 2C, attributed partially to a prolonged drought linked to the El Niño phenomenon, a natural climate phenomenon originating in the Pacific Ocean along the equator. El Niño results in the accumulation of warm waters in the eastern Pacific, releasing heat into the atmosphere. Recent research has found that global warming has led to more frequent and extreme El Niños. A team of climate researchers have found that this current heatwave is 30 times more likely because of climate change.

Bangkok's brutal heat is also due to changes within Bangkok's urban environment. In urban areas, there exists a phenomenon called the urban heat island (UHI), where urban temperatures are higher than surrounding areas due to anthropogenic changes.

The intensity of Bangkok's UHI during the dry season can reach as high as 6-7C, and in the densest areas, the UHI's intensity averages approximately 4C. The urban heat island is thus causing a city that is already oppressively hot during this time of year to become even hotter. Its UHI has become more intense in recent years.

Bangkok's worsening UHI is due to a combination of factors. The first factor is the high level of vehicle emissions, with the number of cars rising from 4.2 million in 1999 to almost 11 million today. Exacerbating the issue is the high level of emissions from these vehicles. Many older cars with diesel engines, low fuel efficiency and high pollutant outputs remain in circulation.

A second factor contributing to Bangkok's UHI is the city's ubiquitous air conditioning. In particular, shopping malls and office buildings use copious amounts of energy to keep their environments cool. The proliferation of air-conditioned environments also leads to greater amounts of heat dumping outside, thereby creating a vicious cycle: the heat dumping increases urban heat island effects and causes further demand for air-conditioned environments. The Metropolitan Electricity Authority has established a pricing structure that does not discourage heavy users from consuming electricity; thus, the price of electricity has had little effect on curbing air conditioning consumption.

A third factor is that the government has offered insufficient incentives for developers to adhere to green building codes and does not penalise those who fail to comply. Consequently, Bangkok's skyscrapers have predominantly adopted a modernist glass-and-steel aesthetic with fully glazed buildings that necessitate high levels of cooling.

The fourth and foremost factor is Bangkok's minuscule amount of green space. According to the BMA, the city has a green area ratio of 1.47 square metres per capita, far less than the 9 square meters per capita recommended minimum by the World Health Organization (WHO). In stark contrast, Singapore's ratio today is over 70 square metres per capita. A recent study found that Bangkok residents need to travel at least 4.5 kilometres on average to reach the nearest green space.

The underlying political-economic reasons for the city's UHI are numerous. The Bangkok Metropolitan Administration is weak both internally and externally. Its Department of Public Parks has limited power and budget, and departments within BMA rarely collaborate with each other. Moreover, the BMA lacks substantial authority, such as the full management of public transport or energy regulations.

Secondly, for a long time, there has been limited leadership and vision at the top of the BMA. It has never prioritised green space. Its budgetary system pushes senior managers to prioritise infrastructure projects over public parks.

Another contributing factor is the private sector's lack of responsibility or interest, as it has consistently prioritised expanding commercial space in downtown public areas over preserving green space.

Developers persist in converting green spaces into malls and residential units, which not only reduces natural cooling but also fuels the demand for further air conditioning and car-dependent lifestyles.

A final reason is that BMA rarely buys back land. While the expense of land presents an obstacle, the BMA also aims to avoid accusations of conflicts of interest, and the process is hindered by numerous regulatory hurdles.

While national efforts to curb carbon emissions are crucial, particularly through the increased investments in wind and solar energy, Bangkok can take immediate steps to become a cooler city.

Green roofs featuring abundant vegetation on building tops present an immediate remedy. Taking inspiration from Germany, where one-fifth of buildings sport green roofs and where two-thirds of cities have mandated their inclusion in development plans, Bangkok could encourage their widespread adoption through subsidies or a similar mandate.

Planting trees is the city's most potent weapon against heat. By prioritising tree planting and treating existing trees as vital infrastructure, Bangkok can maximise their cooling effect. Ideally, these trees would be woven into green corridors, creating connected networks of cooling zones.

Inspired by Singapore's success, Bangkok could also require or incentivise painting rooftops with reflective white paint. This simple yet impactful strategy reduces heat absorption and lowers surrounding temperatures.

The BMA's efforts to expand pocket parks are commendable. However, the city urgently requires more extensive green spaces. One potential solution could involve repurposing abandoned shopping malls and other large buildings or even struggling ones, into new parks.

What is clear, though, is that Bangkok cannot afford to wait to undertake actions such as these -- bold steps are needed to prevent the city from becoming an even more unbearable furnace.

Danny Marks

Dublin City University Assistant Professor

Danny Marks is an Assistant Professor of Environmental Politics and Policy at Dublin City University.

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