Global sea levels rose by approximately 1.5 mm per year between 1900 and 2020, faster than in any century over the past 4,000 years, according to a study published on Wednesday in Nature.
The study, led by researchers from Rutgers University in New Jersey, examines sea level changes from the Holocene to the present, spanning a period of 11,700 years. Lead researcher Yucheng Lin stated that the average rise since 1900 is the fastest in at least four millennia.
This accelerated increase is caused by two phenomena related to climate. First, oceans absorb heat, causing the water to expand. Secondly, the melting of glaciers and ice sheets in Greenland and Antarctica adds freshwater to the oceans. Glaciers, being smaller than ice sheets, respond more quickly to rising temperatures.
The study highlights the risks for China’s southeastern coastline, where rising sea levels are compounded by land subsidence. Major cities in the region, including Shanghai, Shenzhen, and Hong Kong, are situated in delta areas prone to sinking due to their soft, thick sediment foundations.
Human activities, such as groundwater extraction, further exacerbate the situation, accelerating sea level rise even more.
