Melting of ice is a threat

M Fox, of Broseley, (Starmail January 26) gave a clear and cogent explanation of the laws of physics relating to the thawing of ice.

He is quite right - ice melts into less water per volume. From this he surmised that if the world's ice melts the sea level will not rise as predicted.

But most of the world's ice is above sea level on top of land - so when it melts its water will run into the sea and this will cause the sea level to rise.

It is estimated if all the ice on the Greenland land mass melted the seas would rise by seven metres. And it gets worse - another little law of physics states that liquids expand as they get warmer - so as the seas increase in temperature the water in them will expand.

Richard Camp, Wellington