Global mean sea level
Global average sea level has risen about 104 mm since satellite measurements began in 1992 (March 2025), and the rate of rise is speeding up.
Source: Satellite altimetry, NOAA Laboratory for Satellite Altimetry. Data through March 2025. Download the data (JSON).
About this indicator
Sea level rises for two main reasons: water expands as it warms, and land ice — glaciers and the Greenland and Antarctic ice sheets — melts and adds water to the ocean. Both are driven by a warming climate.
Since 1993, radar altimeters on a series of satellites have measured the height of the ocean surface almost continuously, giving a precise global record. It shows a steady rise whose pace has roughly doubled in recent decades. The values here are relative to the start of that satellite record in the early 1990s.
Why it matters: Higher seas mean more coastal flooding, erosion and storm-surge damage for the hundreds of millions of people who live near coasts.
How to read this chart
The vertical axis is millimetres of global mean sea level relative to the early-1990s satellite baseline, so the earliest values sit near zero and the recent ones well above it. Each point is a satellite measurement of average ocean height, with the seasonal cycle removed so the underlying trend stands out.
A global mean hides large regional differences: land still rebounding after the last ice age, ocean currents and local subsidence all mean your own coastline may be rising or falling faster than the average. Read the curvature as well as the slope, because the rate of rise has itself increased. This satellite record updates every few days and runs close to the present.