The recession of the sea ice and the reduction in permafrost -- combined with advances in technology -- have allowed access to oil, mineral and natural gas deposits that were previously trapped in the ice.
The abundance of these valuable resources and the opportunity to exploit them has created a gold rush-like scramble in the high north, with fierce competition to determine which countries have the right to access the riches of the Arctic.
This competition has brought in its wake a host of naval and military activities that the Arctic hasn't seen since the end of the Cold War.
Now, one of the coldest places on Earth is heating up as nuclear submarines, Aegis-class frigates, strategic bombers and a new generation of icebreakers are resuming operations there.
http://edition.cnn.com/2011/WORLD/americas/07/15/larsen.arctic.ice.wars/index.html