News Analysis: Ten days shorter will provide significant cost savings as well as increase vessel life. As long as the ships are regulatory approved for cold weather conditions there is less environmental threat than sailing the Southern Route. Pirates armed with rockets and machine guns could easily destroy ships near them along the Southern Route. The environment would be subject to continued threat due to the belligerence of avaricious men.
Source: http://rt.com/business/south-korea-arctic-shortcut-600/