Sea-level rise is a research concept focused on quantifying, understanding, and predicting changes in the mean height of the world's oceans relative to land or the geoid over various temporal and spatial scales. This field investigates the physical drivers of these changes, primarily the thermal expansion of seawater and the addition of water from melting glaciers and ice sheets, assessing their rates, spatial variability, and attribution to natural and anthropogenic factors. Research into sea-level rise is significant for evaluating coastal vulnerability, informing climate change adaptation planning, and understanding Earth system dynamics.