About Sea Level Rise

Rising global sea level is a critical consequence of climate change. As ocean waters warm, they expand. Also, as air temperatures warm, water from melting ice sheets, polar ice caps, and glaciers enters into our ocean basins.

Sea level rise is not uniform across the globe. Coastal communities are affected by their local sea level rise, which reflects global sea level rise, changes in local land elevation, tides and winds. In Grand Isle, Louisiana, for example, local sea level is rising about 3.5 inches per decade because the land is sinking and sea level is rising (NOAA 2022).

This indicator shows that global average sea level has risen by more than 8 inches (20 cm) since 1880, with about 2.5 of those inches (6 cm) occurring since 1993. Human-caused climate change has made a substantial contribution to sea level rise since 1900, contributing to a rate of rise greater than during any preceding century in at least 2,800 years. In addition to the global average sea level rise, local sea level rise – sometimes called “relative sea level rise” – happens at different rates in different places. Local sea level rise is affected by global sea level rise, but also by local land motions, and the effects of tides, currents, and winds. Many places along the United States coast have seen their local sea levels rise faster than the average global rate. As sea levels have risen, the number of tidal floods each year that cause minor impacts, often called “nuisance floods,” have increased in several U.S. coastal cities. Rates of increase are accelerating in over 80% of East and Gulf Coast tide gauge locations (Sweet et al. 2021).