Heavy rainfall, which has struck the Guangdong province of southern China, has resulted in widespread flooding, leading to the deaths of at least four individuals and causing 10 more to go missing. Rescue efforts saw an excess of 100,000 residents evacuated, with lifeboats being utilised in the process.
The Pearl River delta – a region recognised for its extensive manufacturing activity and high population density – has a notorious history of flooding. However, this week saw unprecedented rainfall amounts, with water levels in the Bei River peaking at a 50-year high on Monday. Over the weekend, hundreds of rescuers were mobilised to aid those trapped in flood-stricken villages after landslides forced road closures. By Monday, most large-scale utilities such as electricity, internet, and phone services were reinstated, while several schools remained shut.
According to the Chinese meteorological service, the downpour is expected to persist until at least Tuesday, while other regions including Beijing have also been inundated by storms and rainfall. A multitude of cities in Guangdong province have broken historical rainfall records for April, with an unusually early onset to the flood season, the earliest since 1998.
The escalating frequency of severe weather occurrences in China has generated speculation about the effects of climate change, with coastal areas being especially exposed. A recent collaborative study between Chinese and American scientists warns of increased sinking in major cities across China due to the rise in flood levels.
The research, which was released last Friday in the Science journal, was carried out by academic contributors from several Chinese universities, including the South China Normal University and Peking University, the Chinese Academy of Sciences, and two American universities. The study discovered moderate to severe subsidence threatening around half of China’s main cities including Beijing and Tianjin, impacting approximately a third of its urban populace. Projections show that by the next century, roughly a quarter of China’s coastal region will be submerged, escalating the flood risk for hundreds of millions of residents. Several factors have been considered as the cause of this subsidence, such as rapid urbanisation, massive building construction, and ground water extraction.
The sinking appears to be linked to various contributory factors, including the weight of buildings and withdrawal of groundwater, according to researchers. There is a flurry of construction of skyscrapers, groundwork for road infrastructure is expanding, and rapid use of groundwater is taking place. They raised an alarm about an elevated risk of coastal flooding unless suitable protective methods are set in place and consistently maintained. They highlighted the proactive steps taken by Shanghai, China’s most densely populated city.
They further noted that the active long-term measures against groundwater extraction in Shanghai and its surrounding regions, is probably the reason behind the observed gradual sinking in those areas.
Using Tokyo as a reference, Robert Nicholls, a climate adaptation professor at the University of East Anglia, highlighted that the city managed to halt its sinking in the late 20th century by guarding their groundwater sources.
He further added that subsidence can endanger the structural soundness of buildings and vital infrastructure and has the potential to amplify the effects of climate change in the context of flooding. This is particularly true for coastal cities where the sinking of the city intensifies the impact of rising sea levels.