• Question: why are water levels rising??

    Asked by laurenshep21 to Angus, Christian, Hannah, Laura, Simon on 26 Jun 2013.
    • Photo: Angus Ferraro

      Angus Ferraro answered on 25 Jun 2013:

      Sea level is rising for two main reasons:

      First, there is more water in the sea! Ice on land is melting because the planet is warming, which causes more water to flow into the ocean. But remember that melting ice in the sea (like in the Arctic) doesn’t cause sea level to rise, because the ice is floating. You can test this by putting an ice cube in a glass and measuring the water level before and after it melts.

      Second, warm water is less dense. This means the same amount of water takes up more space! The oceans are warming up just like the land.

    • Photo: Laura Roberts Artal

      Laura Roberts Artal answered on 26 Jun 2013:

      One thing I would add is that in some places, sea level is actually falling. This is because during the last ice age, the contintnets were really heavy because of all the ice that sat on top of them. This caused them to sink a little if you like. Now that all that ice has melted, the contients actually rise upwards again because they aren’t heavy with the weight of the ice anymore. This means that the sea level around these areas drops a little. This is called Isostatic Rebound. It takes place really slow and it is still taking place from the last ice age.
      You can see evidence of this in Sweden were a lake that once used to be conected to the sea has been cut off and is now totally isolated. Scotland is also rising in relation to the rest of the UK.

    • Photo: Simon Holyoake

      Simon Holyoake answered on 26 Jun 2013:

      great answers from Angus and Laura here!

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