Well, I think you're absolutely right that submarine warfare is something that has to be studied very, very carefully. If you look at the history of both World War I and World War II, submarine warfare was a pretty central issue, although at the end of World War II it was countered pretty effectively with the technology that was available.
I would also point out two other things that generally support what you're saying. There are various techniques used on the seabed and so on from satellites to reinforce the work of maritime NORAD in observing what in fact is happening in these waters.
Also, China, as you said, has 70 submarines. Most of them are diesel submarines, which are very quiet, and they serve the purpose very effectively in the South China Sea and East China Sea, but they're not blue-water submarines. Once they begin to develop nuclear submarines with long-distance capabilities, blue-water capabilities, then, in fact, they are going to be a serious potential threat. I have no doubt that over time this will be an objective: to develop such submarines and, in fact, deploy some of them in the Arctic.
As we know, China has at least one icebreaker, which is pretty remarkable for a state that isn't directly on the Arctic. I think this is based on some reasonable concerns they have. They want to try to shorten transport times and so on from Europe to Asia, but they are also very interested in the resources, and ultimately, they're going to be very interested in the security situation.
I think it is very appropriate for you to introduce this into the discussion.