How to beat extreme climate events
in the tropical metropole in Taiwan
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Taiwan megacity Kaohsiung
Kaohsiung is a tropical city in the South of
Taiwan. It is one of the three larger Taiwan cities. It is a major international port and industrial city in the southwest of Taiwan. Kaohsiung has a land area of approximately 3000 square
kilometers. It accommodates a population of over 2.77 million people; 2 million of them live in the metropolitan area.
The city is known for its industries
and harbor, Love River, agriculture, mountains and history:
• Main industries are the large shipbuilding factories, steel factories, and petrochemical plants. Recently the software technology park and
semiconductor technology park were built.
• The Love River is of great cultural and touristic significance.
• Fruits vegetables and rice are the main agricultural products of Kaohsiung. Kaohsiung is dubbed the City of Fruit in Taiwan. It is the largest
producer of high-value crops such as guava, jujubes, banana and lychees among many others.
• The mountains in the North East are important natural attractions.
• Kaohsiung has a long lasting history as can be seen in some ancient buildings.
Kaohsiung’s known history goes back to 6000 BC.
The densely populated city suffers rising temperature and extreme weather events as a result of climate change. Consequences are damage of
infrastructure and industrial facilities, problems with environmental hygiene and declined agricultural and fisheries production. To cope with these problems a wide range of measures has been
Air pollution in Kaohsiung
Kaohsiung is situated on the lee side of the Central Range and the Northeast Monsoon is weak. As a consequence atmospheric diffusion is
low. Because of the heavy industry Kaohsiung therefore suffers severely poor air quality in autumn and winter. Next to the air pollution Kaohsiung faces problems such as river pollution,
groundwater pollution, traffic congestion, and overcrowding of buildings .
Left: Low visibility in Kaohsiung City during autumn and winter caused by air pollution Right: Concrete jungle in Kaohsiung City caused by overcrowding
(sources: Environmental Protection Bureau, Kaohsiung City Government)
Effects of climate change
The tropic metropole Kaohsiung already faces a wide variety of disasters. The influence of climate change makes them even more complex.
In Kaohsiung, as in so many other cities, extreme temperatures become more and more evident. With disastrous effects. During the
2019 warm winter Yuherbau lychees was only 30% from average. A cold wave in the 2016 winter caused the death of a considerable number of high-value fish species, such as groupers.
Left: Leafy vegetables soaked in water. Harvesting was not possible. (source: Information Bureau of Kaohsiung City Government) Right: A fish farm in Kaohsiung
hit by a cold wave in winter. Fish froze to death. (source: Wun-Da, Guo)
Kaohsiung faces a strong heat island effect. The city has been densely built with concrete buildings and asphalt roads. They
absorb the heat. Households frequently use air conditioners that emit waste heat. But natural ventilation in tropical Kaohsiung is low, humidity is high, and therefore night temperature
remains high. Especially vulnerable people’s health is jeopardized.
The hot and humid environment, combined with warm winters and changing rain frequency cause higher risks for Dengue fever. It is transmitted by
Aedes mosquitos. Therefore the city government cleans up containers with water, flower pots, sewage, drains on roofs and top floors, along with fumigation. In order to prevent mosquitos to lay
Left and middle: Fumigation to prevent dengue fever. On the right: Checking mosquito breeding grounds.
(Sources: Environmental Protection Bureau, Kaohsiung City Government)
Taiwan ranks 7th at the Global Climate Risk Index published by the Germanwatch at the United Nations Framework Convention on Climate Change
(UNFCCC) in 2018. Extreme climate events, such as typhoons, heavy rain and droughts, care serious potential threats.
Kaohsiung suffers three or four typhoons per year. Three extreme typhoons, Morakot in 2009, Fanapi in 2010 and Megi in 2016 caused substantial
damage. An amount of 625 people perished, 76 people were missing and 773 people were injured. Economic losses in Kaohsiung’s agriculture were about €580 million euro and mudflows damaged numerous
roads and houses.
Half of Kaohsiung City is mountainous areas with a maximal height just above 3,000 meters. Its rivers flow west through hills and plains and
enter the estuary of Taiwan Strait at a distance of only several dozen kilometres. Slopes are steep.
The world average annual precipitation is about 973 mm per year. The average of Kaohsiung is with 1884 mm almost twice this amount. Due to
the steep terrains, concentrated rainfall, and the short rivers with fast river flow floodings occur and often causing severe damages. At the same time not much rain water is
kept in the area which can result in periodical droughts.
Left: Downpour inflicted damage on papayas. (source: Liouguei District office, Kaohsiung City). 2nd image: The pumping station at Gaoping River flooded
(source: Water Resources Agency, Ministry of Economic Affairs, R.O.C.). 3rd image: Roads in Liugui District being damaged by heavy rain(source: Liouguei District office, Kaohsiung
City). 4th image: Houses in Liugui District being destroyed by mudflow(source: Liouguei District office, Kaohsiung City). Images below: Two consecutive days of rain caused flooding in
the metropolitan area of Kaohsiung. (source: Water Resources Bureau, Kaohsiung City Government)
Actions taken by Kaohsiung City
Kaohsiung City has strived hard to survive all kinds of natural disasters. Nowadays more and more urban action is taken to prevent them.
Wetland and mangrove restoration
Wetlands and mangroves are restored to what they were before industrialization and urbanization. The City has constructed 21 wetlands, with a
total land area of more than 1,000 hectares. Combined with reservoirs, aqueducts and farmlands, they function as an ecological corridor for a wide variety of species to live. Each wetland has its
own characteristics and functions. The Jhondou Wetlands Park restores the original ecological system of mangroves in the tidal Love River area offering retention capacity to the river resting
place for migratory birds passing Taiwan. The ecological island at Jhondou Wetlands Park preserves a wide variety of native trees
Metropolitan retention basins
Meanwhile about 15 metropolitan style detention basins have been realized. to solve flooding issues as caused by by typhoons, that bring
extremely heavy rain. As sudden heavy rain becomes more severe the City has to integrate detention basins into parks, grasslands, and other facilities to create multiple city landmarks that can
store water and stop flooding.
Kaohsiung City Government established the Green Building Autonomy Regulations. Green roofs including water reservoirs collecting rainwater should
be established. Also buildings can serve as micro detention basins absorbing rainwater. Nowadays the area of green buildings has reached 350,000 square meters. The green roofs also contribute in
lowering the temperature of buildings, lessening the heat island effect.
The next step is to esthablish a stronger evidence base to obtain accurate local information collected through scientific methods. Then Kaohsiung
can evaluate the vulnerability of the City under climate change, and go one step further to find solutions that might benefit the economy.
Drone video on detention ponds (source: Water Resources Bureau, Kaohsiung City Government)
Kaohsiung City is one of the five coastal cities under the project Innovation in Climate Services Provision (INNOVA).
Cities previously introduced by this INNOVA E-zine are:
1. Nijmegen (The Netherlands): River restoration in the Dutch delta.
2. Valencia (Spain): Water resource management.
3. the Bay of Kiel (Germany): Beach resource and environmental issues.
4. Guadeloupe and Martinique region (France): decreased farm production.
Kaohsiung adds the case of a typical tropical metropole. Many other tropical metropoles face similar challenges. The densely populated city suffers rising temperature and extreme weather events
as a result of climate change. Consequences are damage of infrastructure and industrial facilities, problems with environmental hygiene and declined agricultural and fisheries production.
Cities under the INNOVA Project are in different phases of finding ways to cope with problems brought about by climate change. Already many measures have been taken to deal with extreme weather events. Kaohsiung is now in the initial phase to prepare for climate change
adaptation. The city wants to learn to mainstream adaptation measures into municipal policy to ensure that climate change is taken into account in the city planning.
INNOVA is funded by the EU Programme entitled ERA4CS.
This ezine has been produced for INNOVA
Wim Timmermans & Fokke de Jong (Wageningen Environmental Research)
with Kuan-Hung Wei, Yi-Tsen Chen & Sin-Jia Huang (Environmental Protection Bureau, Kaohsiung City Government, Taiwan) and Jo-Ting
Huang-Lachmann (Climate Service Center Germany, Helmholtz-Zentrum Geesthacht, Germany)
and Daphne de Bruijn & Harry Harsema (Blauwdruk Publishers)