The various groups asking for such a moratorium on fracking failed to justify their case (Moratorium vital on gas extraction, Letters, November 16).

The safety of fracking has already been investigated in considerable detail by government.

The groups' objection, then, is to using fossil fuels, which are essential to the provision of reliable electricity supplies and our way of life. I assume in that case they also wish a moratorium on North Sea oil, a notable fossil fuel.

Professor Tony Trewavas

Scientific Alliance Scotland