An iceberg and its reflection in Disko Bay, Greenland
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Rate of polar ice sheets melting has accelerated

29 November 2012 Last updated at 22:44 GMT

The rate at which polar ice sheets are melting is accelerating causing the global sea level to rise 11mm over the past two decades.

The fastest rate of change is in Greenland whereas the bulk of the ice sheet in Antarctica is largely unchanged.

David Shukman reports.