After having survived two heart-stopping earthquakes in as many months this year, I have begun to speculate whether this is a sign that someone "upstairs" has it in for me, or that it is attributable to more earthly causes, such as a link with global warming?

This may not be as daft as it seems. A few years ago in the Antarctic a huge ice sheet (the Larsen B), which is larger than Luxembourg and whose weight was 500 billion tonnes, plunged into the sea.

Both the Arctic and the Antarctic are under threat from global warming.

All this weight shifting must put a tremendous strain on the tectonic plates that in turn could lead to more movement. It is this movement of the plates which leads to earthquakes.

If my surmise is correct then we could be witnesses to more frequent and violent earthquakes in the future.

Phil Shepherdson, Chantry Close, York.