Highest sea level rise

Since detailed records began in 1880, the global average sea level is estimated to have risen by 21–24 cm (8–9 in), largely as a result of melting ice sheets and glaciers, as well as thermal expansion of water caused by warming oceans. The year 2019 represented the greatest increase since satellite altimetry observations began in 1993, with the global average sea level 87.61 mm (3.4 in) above the 1993 average according to the National Oceanic and Atmospheric Administration (NOAA). Year on year, sea level was up 6.1 mm (0.24 in) on 2018. World Meteorological Organization (WMO) data suggests that between 2014 and 2019, the annual average global sea-level rise has been 5 mm (0.2 in); up from 4 mm (0.16 in) in 2007–16 and from 3.2 mm (0.13 in) in 1993.

The average annual rate of sea level rise for most of the 20th century was around 1.4 mm (0.06 in), but between 2006 and 2013, that more than doubled, hitting 3.6 mm (0.14 in) per year.

By 2100, based on current trends, NOAA predicts conservatively that global mean sea level is likely to rise by at least 0.3 m (1 ft) above levels in 2000; in a worst-case scenario with higher pollution rates, that could increase to as much as 2.5 m (8 ft 2 in).