2.7A Long-term sea level change

• Eustatic change = change in global sea level, usually due to a change in the volume of water in the oceans.  ​

  ->Occurs due to melting of glaciers, climate change and thermal processes
• Isostatic change = Rises in local land level causes a fall in local sea level

  -> due to post-glacial adjustments, subsidence and tectonics
• Post-glacial adjustments:

  • weight of the ice depresses the crust in areas below the ice sheets
  • rigid nature of the solid crust means that when sections of the crust are depressed by ice and forced down, adjacent areas are uplifted in a see-saw effect
  • e.g. UK
• Thermal expansion = When thermal heat from the sun expands the ocean, causing it to rise

  -> e.g. Tuvalu