Spare a thought for the iceberg A23a which, after an extraordinary 40-year life voyaging around the southern Atlantic Ocean, is this month expected to die unnoticed close to the island of South Georgia, a mess of “brash ice, small icebergs and bergy bits”. A23a was one of the largest “megabergs” to be spawned in our lifetimes. When it broke away from the Filchner Ice Shelf into the Weddell Sea in Western Antarctica in 1986, it covered an area of around 4,000 sq km – about the size of Hong Kong...