There is quite a lot of news at the moment about a large piece (a little smaller than Swaziland) of ice shelf that recently broke off Antarctica. You can read about it here: National Geographic, Wired, BBC.
Ice shelves are made of ice already floating on the ocean so this incident won’t raise sea levels, but these shelves are holding back glaciers which will raise see levels. As the floating ice shelves break away there is nothing to hold back the land based glaciers which run faster and do raise sea levels.
These ice shelves are notoriously sensitive to warming (another one broke off during a brief warming period around 1920) so they do act as good early indicators of global warming happening – apparently “average Antarctic temperatures have risen 3 degrees (Celsius) over the past 50 years!”
If you are interested there is an busy debate going on in the comments section of the Wired article. Even if you aren’t that interested, I think you should be worried.