what causes sea level change?

sea level rise after 83 meters in the UK (photo credit: rozsavage.com)

 

 

 

 

 

 

 

 

 

Sea level rise is something that concerns a lot of coastal populations across the world. Many feel that the main cause is climate change and whilst this is true to some extent, there are many other causes, particularly in the UK, of sea level change. This has caused the sea levels around the coasts of the UK to rise and fall over millions of years, and the last major ice age had a major impact on the sea levels of the UK and the rest of the world, and it is still having an effect on them today.

Northern hemisphere glaciation during the last...

Northern hemisphere glaciation during the last ice ages. The accumulation of 3 to 4 km thick ice sheets caused a sea level lowering of about 120 m. Also, the Alps and the Himalayas were covered by glaciers. Winter sea ice coverage was much more limited in the south. (Photo credit: Wikipedia)

Isostatic rebound is the process in which the land literally rebounds from the pressure put on it by the vast ice sheets from the last ice age. During this time, the north-west of the UK was covered in these vast ice sheets which was weighing down the earths crust in this part of the UK. When the ice melted at the end of the ice age this pressure was released and the north-west of the UK began to rise or rebound after the pressure from the ice was removed, this also caused the south-east of the UK to sink. therefore the sea level is falling in the north-west and rising in the south-east, and this process is still occurring today, causing small amounts of sea level change.

English: 1993-2010 sea level trends(mm/year). ...

English: 1993-2010 sea level trends(mm/year). Data source:http://ibis.grdl.noaa.gov/SAT/SeaLevelRise/LSA_SLR_maps.php (Photo credit: Wikipedia)

Of course there are other causes of sea level change in the UK. Global climate change is having an effect as well. As the worlds temperature increases, the amount of ice around the poles falls, as more of it starts to melt, this increases the volume of the oceans leading to sea levels rising dramatically. It is predicted that sea levels will rise by at least 2 meters by the end of the century at the current rate of climate change. Climate change was the reason for a rise in sea levels at the end of the last ice age, so much so, that sea levels rose enough to cut England off from the rest of mainland Europe.

Also, a process called thermal expansion can lead to changes in the sea levels. When water molecules in the sea warm up they spread out and expand, which increases the volume of the oceans. For every one degree C rise in temperature, the sea level will rise by at least 0.8m.

Sources

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