Well, surveillance in the north is not up to the challenge of detecting modern incoming conventional weapons. Russian hypersonic weapons, for instance, cannot be detected with any accuracy with the north warning system. I believe you heard from Dr. Huebert on this question yesterday.
From a maritime threat perspective, Canada lacks both underwater and under-ice detection capability. As well, simply because of the size of the Arctic, we do not have a very good idea of what surface ships are operating—at least, outside the Northwest Passage. Right now that's not a critical threat, because ice renders most of those areas inaccessible, but over the next 10 years it's very likely that we will see the emergence of new civilian and hybrid threats using those waters.