[Sheryl Hohle]

Sheryl Hohle asked the Naked Scientists:

I love your show and listen to it while I muck stalls.

I have been pondering a question about climate change/global warming. If the polar icecaps melt and the weight of all that water gets redistributed around the planet, and given that the planet is actually just a ball of molten stuff underneath a relatively thin crust, will the shape of the earth change? Will it bulge more in the middle? Will it spin differently or will the axis change? Or is the weight of the oceans insignificant relative to the earth?

What do you think?

[JimBob]

The areas, such as Greenland and Antarctica will be subject to isostatic rebound, i.e., the land will rise in the mantle - the land will actually gain altitude above sea level. There is little probability it will change the spin, axis or the overall shape of the earth, which is a pear shape withe the larger part in the southern hemisphere. It only amounts to a few feet but does make it a pear!

[thedoc]

Listen to this question on our podcast by clicking here

[Alan McDougall]

Sheryl,

While it will not effect the shape of the Earth, melting of the great Arctic ice sheets might effect the inclination of the poles,

[TonyG]

I'm not so sure that I agree; the earth is in essence a giant gyroscope spinning through space; what would be the result on such a gyroscope of a fairly large distribution of mass from the poles to an even distribution around the earth? would this not be a potential trigger to inversion of poles? I'd love to hear from someone who knows more than me (should not be too difficult).