A comprehensive study led by Lijing Cheng at the Chinese Academy of Sciences reveals that thermal expansion of seawater due to global warming is the largest single contributor to sea level rise over the past six decades. Between 1960 and 2023, warming-induced expansion accounted for 43% of the rise, outpacing contributions from melting mountain glaciers (27%), Greenland ice (15%), and Antarctic ice (12%). The study, published in 'Science Advances,' leveraged improved data from tide gauges, satellites, and Argo drifting buoys to refine historical and recent sea level measurements.

The average annual sea level rise was 2.06 millimeters over the full period, but from 2005 to 2023, it accelerated to 3.94 millimeters per year. This acceleration underscores the ocean’s role as a climate buffer, absorbing about 90% of atmospheric heat from global warming. As water warms, molecular motion increases, causing it to expand—a process known as thermal expansion.

Recent research also highlights how warm ocean water is accelerating ice loss in Antarctica by melting ice shelves from below, potentially speeding up land ice movement into the sea. Separately, a Technical University of Munich study warns that coastal subsidence—driven by groundwater extraction and urban weight—is compounding flood risks in cities. Together, these findings stress the need for integrated climate adaptation strategies that address both global warming and local land-use decisions.