Letter: The size of this glacier will astound you

From John Sherlock, Hughenden Valley, Buckinghamshire, UK

I read that the melting Totten glacier could on its own raise sea levels by 3 metres (11 August, p 4). Really? It must be very big.

The editor writes:
• It is: its catchment area is more than 500,000 square kilometres and researchers in fact say that its total loss could raise sea levels by 3.5 metres.