What is “relative sea level”?
Relative sea level refers to the height of the sea surface relative to a specific point on land. It takes into account both changes in the ocean's surface level (due to factors like land-ice melt, tides, currents, and storm surges) and changes in the elevation of the land itself (due to factors like land subsidence or tectonic uplift).
Caption: Animation depicting relative sea-level rise due to rising ocean surface level and land subsidence due to groundwater withdrawal (Source: Earth Observatory of Singapore)
Read more about how relative sea level can be measured in our blogpost: Charting the Waters: Measuring sea-level from Earth and space
Related: What is “mean sea level”?