Hot nights, extreme rainfall in Hong Kong to increase significantly by 2040s, scholars say
Hong Kong Free Press
A team of scholars from several of the city’s top universities have forecast that extreme weather events in Hong Kong will increase significantly by the 2040s, with the number of hot nights rising by 50 per cent and extreme rainfall by 40 per cent.
The School of Architecture of the Chinese University of Hong Kong (CUHK), together with scholars from the University of Hong Kong (HKU) and the Hong Kong University of Science and Technology (HKUST), announced their latest projections on Monday.
The study, based on climate models and environmental data in Hong Kong, predicted that the 10-year average number of hot nights will rise to 48 in the decade leading up to 2050, up from 32 in the past decade. By then, the city may also see up to 15 consecutive hot nights.
In Hong Kong, hot nights are those when the minimum temperature exceeds 28 degrees Celsius. According to the study, districts including Sha Tin, Tuen Mun, Kowloon, the northern and southern parts of Hong Kong Island, and the airport would be most susceptible to the heat.
Extreme rainfall could reach 230 millimetres per hour in the 2040s, according to the study. That is a 40 per cent increase on the current record logged on September 7, when a historic downpour brought an hourly rainfall of 158.1 millimetres.
The research team, led by CUHK architecture professor Edward Ng, urged authorities to draw up measures to cope with such extreme conditions in advance.
“We cannot design our future city based on past data,” Ng said, adding that the study’s predictions were conservative. Future weather patterns would also be affected by factors such as carbon emissions, he said.
In 2021, Hong Kong pledged to cut total carbon emissions by up to 36 per cent of 2005 levels by 2030 and to become carbon-neutral by 2050, however, a green group warned last year the city had made “little or no progress” towards its climate goals.
The scholars also called for attention to be paid to the adverse effect of the “new normal” of hot weather to residents’ health.
Ren Chao, an associate professor in architecture in HKU, said elderly people and patients with chronic diseases would be more vulnerable to heat stroke and other heat-related illnesses, placing a higher demand on medical services. Authorities should also allocate health care resources to districts more impacted by the heat, she said.
See also: Wealthy Hong Kong districts will warm at a cooler pace than poorer areas, study finds
The group urged the authorities to consider planning for extreme weather in major infrastructure projects such as the Northern Metropolis and the Kau Yi Chau artificial islands. They also called on the public and corporations to make a concerted effort to reduce carbon emissions.
Climate crisis
In August, the city’s Observatory recorded an average temperature of 29.7 degrees Celsius – 1 degree above normal levels – and the warmest August since records began in 1884. The Observatory has also predicted that 2023 is likely to be one of the hottest years on record.
In September, the record-breaking rainfall caused severe flooding and landslides, grinding the city to a halt as the Observatory’s highest rainstorm signal remained in place for over 16 hours.
In response to the extreme weather events, Lee said in his second Policy Address in October that the government would study measures to enhance the city’s preparedness, response and recovery to extreme weather events.
Environment experts, however, said that the city needs more progressive and proactive environmental policies to address the imminent climate crisis, including the need to conserve the natural environment and to speed up the transition towards green energy.
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