As a result of climate change, sea levels are rising. The main cause of this is the melting of the polar ice sheet and glaciers. However, there are also other factors such as the thermal expansion of water and local extreme weather events.

Source:

IPCC. (2021): Climate Change 2021 The Physical Science Basis WGI. In Bulletin of the Chinese Academy of Sciences (vol. 34, number 2) from p.1289