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 taken.

 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 of buildings

(sources: Environmental Protection Bureau, Kaohsiung City Government)

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 eggs.

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)

Kaohsiung City has strived hard to survive all kinds of natural disasters. Nowadays more and more urban action is taken to prevent them.

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

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)