The seas around China in a warming climate

Anthropogenic forcings have led to multifaceted changes in the seas around China, which include the Bohai, Yellow, East China and South China Seas, affecting the functions and services they provide. In this Review, we synthesize physical, biogeochemical and biological findings to understand how the seas around China have changed and are projected to change under a warming climate. The average surface temperature of these seas increased by 0.10–0.14 °C dec–1 over 1950–2021. Meanwhile, the annual frequency and average intensity of marine heatwaves increased by 1–2 dec–1 and 0.1–0.3 °C dec–1 since the 1980s, respectively. Terrestrial input has increased nutrient concentrations and composition changes in coastal waters. These warming and nutrient changes have increased the severity of hypoxia and acidification, leading to complex changes in primary productivity. Changes to marine organisms such as plankton, benthos and fish are also apparent, including the northward invasion of warm-water species and miniaturization. These observed changes are projected to persist into the future. These coupled physical–ecological changes highlight the need for strengthened multidisciplinary oceanographic research in the seas around China. Increasing temperatures in the seas around China have a range of physical, biogeochemical and biological impacts. This Review outlines historical and projected changes in these seas and the implications of these changes for marine ecosystems.