TAIPEI (Taiwan News) — Taipei temperatures have risen 1.8 C from 1923 to 2022, while the global average is only 1.2 C.
Taipei ranks second in terms of heat increases amongst 20 Asian capitals over the past century, according to Berkeley Earth, per Common Wealth Magazine. Even more worrisome is that island countries do not typically overheat due to nearby oceans which have temperature-regulating effects, according to National Cheng Kung University (NCKU) architecture professor Lin Tzu-ping (林子平).
Lin is concerned that temperatures could become even hotter with the arrival of El Nino, which is bad news for those in Taipei. Some of the heat problems Taipei faces are its own doing, either related to poor urban planning or too many people in the city.
1. Taipei is a basin surrounded by mountains
Taipei is hot mainly due to its geography, a basin that is surrounded by mountains. This blocks winds that would otherwise provide a cooling effect.
The basin effect is particularly apparent in Wanhua (萬華) and Zhongzheng (中正) districts, which sit at the bottom of the Taipei Basin. In Wanhua, many houses are typically sheet metal structures, which heat up quickly and are slow to cool down.
2. High-rise waterfront buildings block cooling winds
A long row of high-rise buildings occupy Banqiao District's waterfront, which sits on the edge of the Taipei Basin. These buildings effectively become a high wall, blocking cooling winds from blowing into urban areas.
Wind is the basic way to cool cities around the world. Germany began studying the effect of regional wind on urban temperature distribution as early as the 1930s.
However, the concept of "wind corridors" has only recently been included in Taipei’s urban planning, according to Ming Chuan University Urban Planning and Disaster Prevention associate professor Shih Wan-yu (石婉瑜), per Common Wealth Magazine.
Two years ago, NCKU researchers drew a map of regional wind corridors and began to carry out a new project to cool off Taiwan's cities. However, they found that opening wind corridors in Taipei was largely impossible due to existing buildings.
As for Taichung, the wind direction and road direction are both aligned along a north-south axis, allowing good ventilation. But the Taipei Basin is much different with winds traveling northeast and southwest, though roads are aligned on an east-west and north-south axis.
This means naturally occurring wind corridors face too many obstructions. Furthermore, many tall buildings line major roads, effectively cutting off wind corridors or leading them to become thin and narrow.
3. Older communities are too dense
Many communities in Taipei are located near streams or canals, which provide a cooling effect in the summer. But with the city's development, many of these streams have been covered in cement or rerouted. Additionally, low-lying buildings and narrow alleys prevent air flow.
Taipei City is focusing on two major directions for urban planning. For older urban areas, such as Zhongzheng District and Wanhua District, where development is already saturated, the only solution is to wait for urban redevelopment. In the meantime, builders are encouraged to undertake more urban greening, shading, or architectural designs that promote ventilation, according to Common Wealth Magazine.
As for newer communities, Taipei’s urban planners have a slew of tools at their disposal. Beitou and Nangang are the two largest air intakes in the Taipei Basin, and new projects in these areas are required to comply with regional ventilation regulations before construction can start.
Regulations require buildings to be at least four meters from the closest road, and the minimum distance between high-rise buildings must not be less than six meters.
4. Foehn winds
Leaving the Taipei Basin, one of the closest communities is the Shilin District at the foot of Yangming Mountain. It is located on the leeward side of the mountain, which typically experiences the phenomenon of "foehn" winds that are hot and dry. While this may be beneficial in the spring and winter, in the summer these winds can dramatically increase heat.
Furthermore, a sprawling night market in Shilin, largely made up of low-lying buildings and sheet metal structures, can cause temperatures to rise rapidly. Over the past three years, Shilin has been the hottest administrative district in Taiwan, making it a difficult place to live and conduct business during the summer months.
5. Too many people and vehicles
Having a car does not protect individuals from the oppressive summer heat. In fact, the number of vehicles on city roads and their carbon emissions heat up the city. The same is true for those staying in air-conditioned residences, which spew hot air into the community.
Many climate experts have talked about the urban island effect, in which a city’s roads, infrastructure, buildings, and human activity lead to excessive heating when compared to rural areas.
In Taipei’s Xinyi District, buildings facing an easterly direction should be well ventilated, but air-conditioning units from high-rise commercial buildings can be an unexpected heat source.
In the heat of summer, the only escape may simply be leaving the city. But this too may not be available in the future as failure to cool down "hotspots" in the city could allow them to link together and form a large-scale hotspot which could cause even more problems for Taiwan.
