A 20km-wide iceberg broke off a Greenland ice shelf recently. It has been used by the media as a powerful emblem in their coverage of global warming. But there's a huge irony here. Because, if anything, a larger iceberg is indicative of more snowfall and greater ice mass rather than warming temperature -- more snow and ice making for a faster flow and huger ice blocks. Warmer temperatures would cause the opposite to this, with the ice receding, and hence less ice for breaking off into big chunks.