The dispute with Denmark is over Hans Island, which lies between Greenland and Canada. Whoever gets international recognition for their claim, will own any oil, or other resources, in the waters around the island. Canada and United States disagree over whether Canada controls the Northwest Passage (the sea route from the Atlantic to the Pacific via the Arctic). There are also border disputes over who controls what in the Beaufort Sea. Canada and Russia have overlapping claims in the Arctic waters where their borders meet.
Canada is a miniscule military power, and only has a chance at fighting an attempt by Demark to settle their dispute by force. Against the United States and Russia, negotiation is the only option. But those talks have been going on for a long time. If oil is discovered in disputed waters, and Russia or the United States started drilling, Canadas only recourse would be to deploy as many lawyers as it could afford, and hope for the best as the battle moved through international courts.
OK, so maybe this would never develop into a shooting war (or wars), but Canada has become more aggressive at defending its claims along its Arctic coast. Canada is second only to Russia in the amount of Arctic waters it has claims to. But this has brought it into conflict with other Arctic powers. These include the Russia, the United States and Denmark (which owns Greenland). Canada has been sending more warships to patrol these northern waters in the Summer, which is the only season the ice is thin enough for a ship to move around up there. Canada has also been conducting more air and ground military exercises up north as well. But all of the actual disputes are in the coastal waters, and nearly all are about money, or the potential for making lots of it.