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Thermal expansion

'Thermal expansion' is the tendency of matter to change in volume in response to a change in temperature.

In detail

In the context of sea level rise, thermal expansion is the process by which the absolute sea level increases as water temperature increases. At the end of the 20th century, thermal expansion and melting of land ice contributed roughly equally to sea level rise, while thermal expansion is expected to contribute more than half the rise in the upcoming century.

Find out more


  • The UKCP09 Marine & Coastal Projections report includes discussion of what determines sea level in section 3.1 and describes the approach adopted in UKCP09 in section 3.2.
  • The IPCC Fifth Assessment Report, Working Group 1 report The Physical Science Basis , Chapter 13 also contains useful information.