These changes are profoundly altering the Alaska landscape, but for the Coast Guard, the changes causing the most concern have to do with the lengthening ice-free seasons off Alaska’s Arctic shores. Where there’s water in the U.S. exclusive economic zone (EEZ) – and particularly where there are people doing things on or in that water – the Coast Guard is required by law to fulfill 11 statutory missions.

As more of the Arctic becomes open water for longer periods during the season, wind speeds and wave heights increase. Many northern Alaska coastal communities, relying on whaling and sealing for subsistence, are located near the sea, where ice historically has sheltered them from storm surges. As the president pointed out, this is no longer the case for many coastal communities – such as Kivalina, the Inupiat village of 400 on a fragile barrier island in the Chukchi Sea, which will simply have to move. The U.S. Army Corps of Engineers projects that Kivalina will be under water within the next decade.

The northernmost U.S. city, Barrow, on Alaska’s North Slope, experienced a frightening storm in late August, when waters from the Beaufort Sea smashed a temporary seawall, flooded a coastal road, swamped numerous structures, and flooded an inland lake, one of the town’s few sources of fresh water. The storm happened to coincide with a visit from Coast Guard Commandant Adm. Paul Zukunft, who pointed out that, at the time, there was no sea ice within 150 miles of Barrow.

“Coastal erosion is something new for that domain,” Zukunft said. “I didn’t have to be a therapist to read the anxiety on their faces, the concern for this village that’s been there for a millennium. You could see the wheels turning: ‘Are we going to have to find higher ground? Where is it?’ If they have saltwater intrusion, how would you bring fresh water into the village of Barrow – a logistical challenge at best? There are very serious concerns for how their way of life is being affected by climate change.”

By the 2030s, the Arctic is expected to become seasonally ice free – a circumstance that, while certainly unwelcome among communities such as Barrow, will allow for increased human activity, both commercial and recreational, in Arctic waters:

Energy and mineral extraction. The U.S. Geological Survey estimates the Arctic may contain 25 percent of the world’s undiscovered oil and natural gas resources – and 20 percent of these lie within U.S. territory. In North America, the recent shale-oil-and-gas revolution, and the accompanying drop in oil prices, has dampened much of the enthusiasm for Arctic drilling. Nevertheless the melting ice continues to make these deposits more accessible – and as summer 2015 has demonstrated, the region is subject to rapid change.

Shipping. More vessels are crossing the Arctic than ever before, mostly along Russia’s Northern Sea Route – though these transits are still measured in the dozens, compared to the 17,000 ships that pass through the Suez Canal every year. In an interactive guide released earlier this year, titled “The Emerging Arctic,” the Council on Foreign Relations (CFR) examined the economic opportunities and environmental risks in the region. CFR experts estimated the Northern Sea Route may become a significant route for shipping bulk cargo such as oil, coal, and mineral ore in the near future.

Despite the fact that the Coast Guard has been leading the way in the U.S. Arctic for a century and a half, it faces several significant obstacles in adapting to the current pace of change. One is simply a lack of domain awareness: Less than 5 percent of the Arctic, Zukunft said, has been charted to 21st century standards.

The Northwest Passage, through the narrow straits of the Canadian archipelago, has historically been considered the more treacherous route because of its nearly permanent ice pack, but dozens of commercial ships now traverse the passage annually. Shipping goods from the Pacific to the Atlantic via the passage is estimated to be 30 percent cheaper than using the Panama Canal.

Fishing. The Bering Sea, just below the Arctic Circle, already contains more than half the U.S. fish stocks. The National Marine Fisheries Service (NMFS) has banned commercial fishing north of the Bering Strait until more is known about the effect of sea ice loss on these populations, but 2015 ocean surface temperatures were the highest in recorded history, and evidence continues to emerge that some species have begun migrating northward, seeking cooler water with better oxygenation. It seems increasingly likely that industrial-scale fishing will someday occur in the Arctic. In July 2015, the United States and the four other nations bordering the Arctic – Canada, Norway, Denmark (Greenland), and Russia – signed an agreement to prohibit commercial fishing in international Arctic waters until more research is done.