China's sea levels reached their highest on record last year, swelled by rising water temperatures and the melting of glaciers and polar icecaps, according to its latest government report.
Coastal sea levels were 84 mm (3.3 inches) higher in 2021 than the average over the period from 1993 to 2011, the National Marine Environmental Monitoring Centre said in an annual bulletin.
Saturday's report warned that rising sea levels brought by climate change were having a "continuous impact" on the development of coastal regions, and urged authorities to improve monitoring and bolster early warning and prevention efforts.
Coastal sea levels around China have now risen by an average of 3.4 millimetres (0.13 inch) a year since 1980, higher than the global rate over the period.
Although the temperatures of China's coastal waters fell slightly in 2021 from the previous year, they were still the third highest on record and 0.84 degrees Celsius above the 1993-2011 average.
What is the impact of rising sea levels on Chinese cities?
Last year, the environment ministry forecast a rise of another 55 mm to 170 mm (2 inches to 7 inches) in coastal water levels during the next 30 years, which would require a greater effort by China to protect its coastline.
The long-term effects of such rise include erosion of coastal ecoystems and the loss of tidal flats, while coastal cities face greater risks of floods and salt tides.
Its east coast cities have begun making contingency plans against rising sea levels, with the commercial hub of Shanghai looking into building new drainage tunnels and tidal gates.
Projections such as those by the Intergovernmental Panel on Climate Change (IPCC) indicate that rising sea levels are a "serious threat to China's coastal cities and populations".