That turned dark quickly. Instead iced over and killed off sea life in the Barents Sea and the Gulf of St. Lawrence. But there are more drastic scenarios for the Gulf. "Right now there is a bit of a cold war with the Norwegians that the Russian side doesn't like," Bremner said. "They have an oil rig there now which they've been trying to unload, they've tried to offload it to Norway, they've tried to tow it to Norway, they've tried to get this ship which goes very slow and is very difficult to handle. They can't move it from this particular spot that they wanted to tow it to for oil storage." That could set the stage for more conflict. "If it's an oil platform, that's a very easy thing for the Russians to threaten to attack, and they could do it," said Bremner. A lot of the conflict in the Arctic stems from an economic imperative. "They know that the last thing they need is conflict with the West," says Arno Luik, author of 'Arctic Circle — Arctic Conflicts', and a professor at the Norwegian University of Science and Technology in Trondheim. Russian media have already talked of retaliation. "It is a matter of fact that the security situation has changed, both in the North and elsewhere," said Konstantin Sivkov, Russian defense minister, in April. "The Arctic represents a serious military challenge, and we will have to enhance the defensive potential." The Pentagon sees an Arctic where the U.S. is a minor player on the sidelines, but in reality, the Russians are the ones in the hot seat. "Right now it's the Russians who are showing their teeth," said Bremner. "Russia is the one showing its teeth and saying 'We're going to do things differently.' The U.S. is very worried about that and they see Russia sort of flexing their muscles." The U.S. is looking to maintain the Arctic's environmental status quo, but Russia wants it broken. So far, Arctic conflict is on the horizon. Copyright 2020 NPR. To see more, visit https://www.npr.org. DAVID GREENE, HOST: The U.S. Navy has just completed a massive war game in the Arctic. It happened in Norway, and it was a clear reminder that tensions in the region are increasing. From that country, NPR's Joanna Kakissis reports. JOANNA KAKISSIS, BYLINE: It's the start of May, and cold and snow are still here. But in the Arctic Circle, the sun's out and so are Russian military planes. (SOUNDBITE OF AIRPLANE BLADES) KAKISSIS: Thousands of people are here at the naval air station at Bardufoss, which overlooks the North Sea. This Norwegian air base is the same place where Navy SEALs did part of their training for the raid on Osama Bin Laden. (SOUNDBITE OF MUSIC) KAKISSIS: It's a strange mix - the cold and frozen air, and the crisp Norwegian music playing through the planes. It's all made for an unusual war game, which the Navy calls Trident Juncture 2018. (SOUNDBITE OF ARCHIVED RECORDING) UNIDENTIFIED ANNOUNCER #1: (Speaking in foreign language) KAKISSIS: Here in Trondheim, Norway, the U.S. Navy flew an Aegis destroyer, but there are also warships from other nations, like a Russian corvette and an Argentine frigate. The exercise is also bringing out the U.S. Air Force, the Russian Air Force and the Royal Norwegian Air Force. (SOUNDBITE OF GUNFIRE) KAKISSIS: Even though the war game is officially over, some military personnel will be here for weeks. I asked Maj. Nils Klara (ph), a Norwegian Defense Ministry spokesman, what they're doing here. He said, quote, "It's just a little bit of preparation to improve and to learn what is already there." The war games also include live-fire exercises. The Norwegian army has joined with U.S. and Canadian troops to repel a simulated Russian invasion, called Red Dawn. (SOUNDBITE OF AIRPLANE BLADES) KAKISSIS: It was a clear night, and we were able to hear the sound of the jets and drones buzzing in the night sky, over the North Sea. Most of the real jets were on the ground or in the air in Russia, but this war game takes place on Norwegian soil. ROGER BREMNER: There were fighter jets flying over the North Sea to try and simulate a Russian combat mission. KAKISSIS: Roger Bremner is an Arctic specialist at the Washington, D.C.-based think tank, Center for Naval Analyses. He says there's a lot riding on the war games. BREMNER: From the U.S. side you can learn things that work, what can be improved. From the Russian side, you're trying to figure out what are the potential problems and how to counter that. I know in the Russian press this is described as the biggest Arctic war game since 1981. It really was more of a planning exercise. KAKISSIS: More training. Still, Bremner says Russia does have the edge in the region, which is why this war game was important for the United States. BREMNER: How many times do you think that the U.S. and the Western nations take a look at their strategy and decide to do things differently, to take a different route. This was the first time I think that the U.S. went in the Arctic, and they really set a very strong message that they were there and, therefore, it was a strong message for the Russians. (SOUNDBITE OF AIRPLANE BLADES) KAKISSIS: It's a very rare picture - Russia's president, Vladimir Putin, watching the first of the exercise as it happened. The U.S. is planning to return to the Arctic, next year. Maybe this war game was successful enough for the U.S. to expand its Arctic footprint. BREMNER: We can come back next year and really make a statement that this is going to be a new norm and that is going to drive the international activity in the Arctic to change. KAKISSIS: Even Russia, the powerhouse in the Arctic, knows that, as its top defense minister warned this week. KONSTANTIN SIVKOV: (Speaking foreign language) KAKISSIS: At a ceremony in the Russian capital last month, Defense Minister Sivkov called out the U.S. for building up its own Arctic presence. SIVKOV: (Through translator) I believe that we do not need a conflict in the Arctic, although there are reasons for concern. I believe this is the place where the Arctic countries must and will join their efforts. KAKISSIS: Russian media have already talked about the U.S. being on Russia's back, and about military retaliation. And if Russia does fight, it would be for territory and for power, not for ecological reasons. We learned from our visit in the icy waters off of Norway that polar bears are very vulnerable in a conflict. Arno Luik is the author of Arctic Circle — Arctic Conflicts. He's a professor at the Norwegian University of Science and Technology in Trondheim, Norway, and he