A huge chunk of the Petersen Glacier has broken off in Greenland and is heading south, believed to be a victim of global warming.  This ice island, three times the size of Manhattan, may be heading for the Canadian shore of Newfoundland, where there are numerous oil rigs.  If such a massive piece of ice moves into that area, the danger of yet another massive oil spill is a possibility.  This is the same area where an iceberg sank the Titanic in 1912.  To further emphasize the size of this ice monster, if it were to melt, it would raise global sea levels 20 feet.  Scientists point to the almost impossible task of changing its direction by towing it because of its size and weight.  It is hoped that the warmer waters to the south of its current location, and impacts with small rocky islands, will help break it up into smaller chunks.