Urbanisation pushes up city temperatures
HCM CITY — The fast pace of urbanisation has been blamed for the rise in temperature over the last three decades in HCM City, the country's biggest city.
According to recent research by the Southern Centre for Hydro-Meteorological Forecasting (SCHMF), the city's temperature has increased by nearly 1 degree Celsius over the past 30 years.
This year the highest temperature has been 36 to 37 degrees Celsius, with the hottest period expected to be from March to the middle of May, according to the SCHMF.
The centre's director, Nguyen Minh Giam, said high temperatures have had the worst effect on the city's central districts, including 1, 3, 4, 5, 10 and 11, which have fewer green zones and more concretised areas.
Experts said urbanisation was the main cause behind higher temperatures in the city of more than 8 million.
The increase in concrete surfaces and reduction of green sites and narrowing of waterways have caused the city to turn into an "urban heat island" (UHI), according to experts.
Luu Duc Cuong of the Ministry of Construction's Urban-Rural Architecture and Planning Institute said increased concrete coverage in HCM City had resulted in the UHI effect, which had caused a rise in temperatures as well as a higher volume of rainfall.
Urbanisation in HCM City began in the late 1980s, according to Tran Thi Van of HCM City National University's Natural Resources and Environment Institute.
By 2006, the urban land area covered more than 47,000ha or 22.4 per cent of the total area, about 19 per cent higher than that in 1989 when urbanisation began, Van wrote in her paper "Urban heat island under the impact of urbanisation in HCM City, from remote sensing data".
Urbanisation was fastest during the 2001-06 period, with the population growing by 83 per cent to 85 per cent during that time, according to Van.
As a result of urbanisation, 47 canals with a total area of more than 16ha have been filled up. Around 7.4ha of the Binh Tien Lake is also full.
Since 1998, the total area of park and botanical gardens in the city has fallen by nearly 50 per cent to around 530ha.
Cuong said that uncontrolled urbanisation had directly and indirectly caused chronic flooding in HCM City in the past few years.
Population growth has resulted in an increase in personal vehicles, air conditioners and refrigerators, which have contributed to the rise in greenhouse gas emissions that have caused the temperature to go up, according to experts.
Giam said the city should expand green areas, which would help the entire area to "cool down".
Green-area expansion is a focus in the city's construction plan through 2025, approved by Prime Minister Nguyen Tan Dung in 2010, according to the director of the city's Planning and Architecture Department, Tran Chi Dung.
As a first step, the city would keep the current 235ha of green area and build more botanical gardens and lakes in different areas in the city.
In an effort to reduce greenhouse gas emissions and pollution, the Department of Transport has also been taking measures to decrease the number of personal vehicles by promoting public transport and replacing buses run by fossil fuel with those run by environmentally friendly gas. — VNS