Understanding Sea Level

Key Indicators

Global Mean Sea Level

This dataset contains the Global Mean Sea Level (GMSL) generated from the Integrated Multi-Mission Ocean Altimeter Data for Climate Research (GMSL dataset). The GMSL is a 1-dimensional time series of globally averaged Sea Surface Height Anomalies (SSHA) from TOPEX/Poseidon, Jason-1, OSTM/Jason-2 and Jason-3. It starts in September 1992 to present, with a lag of up to 4 months. All biases and cross-calibrations have been applied to the data so SSHA are consistent between satellites. Data are reported as changes relative to January 1, 1993 and are 2-month averages. Glacial Isostatic Adjustment (GIA) has been applied. These data are available in ASCII format. Reference: Beckley et al., 2017,

Data shown are latest available, given time needed to allow for processing.


Satellite Altimetry (TOPEX/Poseidon and Jason I, II, III)


Data source: Satellite sea level observations. Credit: GSFC/PO.DAAC
Rate of Change
(± 0.4) mm/yr
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Sea level trends (1993-2016) For over 20 years, satellite altimeters have measured the sea surface height of our ever-changing oceans. This image shows the 20 year trends of rising seas across the globe from 1993 to 2016. The grids and figures were produced at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under the NASA MEaSUREs program (version JPL 1603).

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