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Accelerating Sea Level Rise

From 1880 to 2025, global mean sea level rose by about 25 centimetres — and it will keep rising for centuries.

Accelerating Sea Level Rise

Sea level is rising in most areas of the world and will keep rising for many more centuries due to ice loss and rising ocean temperatures caused by climate change. By 2100 some places could see around 1 meter of sea level rise, but the exact amount depends on future levels of warming.

Global mean sea level is the average height of the entire ocean surface. The graph shows the change in sea level since 1880 measured by tide gauges located around the coasts,1 and by satellites over the last three decades.2 Although there are years when global mean sea level rises little or not at all, the long-term trend is unequivocal: sea level has risen by about 25 cm from the 1880–1900 average, and it has been rising at about 3 mm per year over the 1993–2025 period.

Close examination of data also shows that the annual rate of rise has increased – from 2.0 mm a year in 1993 to 4.4 mm a year in 2023.3

What causes sea level rise?

There are two main reasons for sea level rise and both are connected to climate change. First, warming causes melting of land-based ice sheets and glaciers which results in the addition of fresh water to the oceans.

Ice loss, particularly in Greenland and Antarctica, has been the largest contributor to the sea level rise over the last couple of decades.

Secondly, ocean temperatures are rising because over 90% of heat accumulating on Earth due to the strengthened greenhouse effect (see also: greenhouse effect) is absorbed by the oceans. Warming oceans lead to water expansion which has contributed to about one third of sea level rise over the last decades.

The rise is uneven over the world

The averaged global sea level rise masks very different patterns in different places over the planet. Sea levels rise significantly in some parts of the globe, remain relatively flat in others, and even decrease in some areas.

In some coastal cities, particularly where land is also subsiding (e.g., Galveston on the Gulf Coast in USA, or Bangkok in Thailand) local sea level rise is considerably higher than the global average.4

What does the future hold?

Sea levels will continue rising for centuries to millennia because of melting ice even if warming were to stabilise. IPCC projects global mean sea level to rise between 0.28 and 1.01 metres in 2100, depending on future greenhouse gas emissions.5 Some regions will see higher levels than the global average.

By 2300, IPCC projects up to 3 metres of global sea level rise even for the scenario of keeping global warming below 2 °C – a target that current emissions trajectories make increasingly unlikely. Scientists also warn that higher sea level rise cannot be ruled out due to deep uncertainties in ice sheet processes (i.e. how fast ice sheets may disintegrate and collapse).

Regardless, even a relatively small change in sea level can have damaging impacts in coastal areas due to much worse storm surges, flooding, salinisation of freshwater sources, erosion of land, and infrastructure damage. Future sea level rise poses a serious threat to hundreds of millions of people living around the coast.

Some governments in affected areas are trying to prepare for these future risks. For example, the Netherlands, where one third of the land already lies below sea level, is investing in infrastructure to protect the country from a sea level rise of up to 1 metre by 2050 and already planning for a rise of up to 5 metres.6 However, protection is costly, and people in many parts of the world cannot afford such expenses.

Footnotes

  1. Church, J.A., White, N.J. (2011). Sea-level rise from the late 19th to the early 21st Century. Surveys in Geophysics, 32, 585-602. DOI: 10.1007/s10712-011-9119-1. The dataset is accessible at CSIRO. Dataset accessed 2026-02-05. ↩

  2. NASA-SSH. (2025). Global Mean Sea Level from Simple Gridded Sea Surface Height from Standardized Reference Missions Only Version 1. PO.DAAC, CA. Dataset accessed 2026-01-05. DOI: 10.5067/NSIND-GMSV1. ↩

  3. Hamlington, B.D., Bellas-Manley, A., Willis, J.K. et al. (2024). The rate of global sea level rise doubled during the past three decades. Commun Earth Environ 5, 601. DOI: 10.1038/s43247-024-01761-5. ↩

  4. To track many different places around the globe, you can check the sea level explorer at Earth.gov. ↩

  5. See Figure SPM.8 (d) of IPCC’s AR6 WGI Summary for Policymakers: Intergovernmental Panel on Climate Change. (2021). Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to AR6. DOI: 10.1017/9781009157896.001. ↩

  6. See the Dutch Delta Programme and connected Sea Level Rise Knowledge Programme: National Delta Programme. ↩