For the second year in a row, sea levels along China’s coastline have reached record highs, increasing faster than the worldwide average and posing a major threat to coastal cities like Shanghai, the world’s financial center.
China’s coastline sea levels in 2022 were the highest since records began in 1980, measuring 94 millimeters (3.7 inches) above “normal,” which is the average for the years 1993 to 2011, a Ministry of Natural Resources official said during a news briefing on Wednesday.
In comparison to 2021, when the previous record was attained, the swell was 10 mm higher.
The temperature of China’s coastal waters has increased significantly due to global warming, and the rise in sea levels has accelerated, said Wang Hua, head of the marine forecasting and monitoring department at the ministry.
China’s sea levels have increased by an average of 3.5 mm per year since 1980, and an average of 4.0 mm per year since 1993 – higher than the global rate over the same periods, Wang said.
The global mean sea level has risen 3.4 mm over the past three decades, according to NASA.
“In the last 11 years, from 2012 to 2022, China’s coastal sea levels were the highest since observations were first recorded,” Wang said at the news conference, which released the latest annual report on China’s sea levels.
About 45% of China’s population of around 1.4 billion and more than half of the country’s economic output comes from coastal regions.
The Chinese coast is home to important metropolises including Shanghai, the country’s most developed and richest city, as well as the port city of Tianjin and the tech hub of Shenzhen.
Over the past four decades, rising sea levels along the Chinese coast have caused long-term effects, including the erosion of coastal ecosystems and the loss of tidal flats. They have also affected groundwater supply and increased the damage caused by storms, floods and salt tide intrusion, Wang said.
While the sea swelled, land in coastal regions had sunk, exacerbating the problem, he added.
In 2022, high sea levels along the Chinese coast aggravated the impact of storms, dealing a severe blow to the provinces of Guangdong, Zhejiang and Shandong. The rises also contributed to heavy coastal flooding in Zhejiang and Hainan province, causing great economic loss, according to Wang.