Question: do you think all the magma that is coming to the surface is making the world bigger and do you think that is the cause of globel warming

Ceri-Wyn Thomas answered on 17 Jun 2010:

No! The magma erupting to the Earth’s surface is not making the planet bigger. Firstly, eruptions don’t cover entire continental surfaces with magma- it’s very localised. But the main reason that lots of magma won’t cause the planet to increase in size is this: Magma can rise up at plate boundaries (the edges of the crustal plates that cover our planet) these are called CONSTRUCTIVE plate boundaries, There is one of these running through the Atlantic. These two plates are spreading apart as more magma rises up (causing the Atlantic Ocean to widen daily!). However, at other plate boundaries- the plates themselves are being pushed underneath other plates (These are DESTRUCTIVE plate boundaries) You get a lot of volcanos and earthquakes at these boundaries (like the Pacific Ring of Fire). So tectonic plates are in a continual state of motion with both the creation and destruction of their material occurring simultaneously. new magma coming up to the surface doesn’t cause the overall size of the Earth to increase.

However, volcanic eruptions can release large amounts of CO2 and other gases into our atmosphere and this does contribute to warming but there’s very little we can do about it.