and shipping lanes and new paths to wage war. >> we are well aware we are in a great power competition environment. and the arctic is one piece of that. >> great power competition, talking principally about russia, but also china? >> russia and china two of great powers that are trying to catch up with us as fast as they can. >> this year these exercises called ice x are taking on new emergency. british joined in first time and u.s. submarine forces are refocusing on mission dating to the cold war. >> one of the primary missions is to be able to leverage our offensive weapon like a torpedo against a threat. so there has been a shift in emphasis in our ability to do that. >> operating under the arctic presents unique challenges with no access to gps navigation,