President Barack Obama aboard the "Viewfinder," touring Resurrection Bay, Alaska on Tuesday. Photos by CNN's Jim Acosta.

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President Barack Obama took a boat tour of an Alaskan bay to see a shrinking glacier

The three-hour tour was across the blue waters of Resurrection Bay near the town of Seward

The trip also featured sightings of humpback whales and endangered seals

On Resurrection Bay, Alaska CNN  — 

It was exactly the spectacular Alaskan backdrop the White House had envisioned as President Barack Obama cruised by boat up to a shrinking glacier and past endangered sea lions to deliver a visual message on climate change.

Riding aboard a large touring boat named “Viewfinder,” Obama ventured into Kenai Fjords National Park on Tuesday for an up-close look at Bear Glacier. The 12-mile-long glacier, the largest in the national park, has shrunk by two miles in just 15 years, park rangers said.

Pausing near the glacier to answer a couple of shouted questions from reporters aboard a separate press boat named “Wild Lander,” Obama pointed to the enormous chunks of ice that have broken off as the Southern Alaska climate warms.

Obama aboard the "Viewfinder," touring Resurrection Bay, Alaska on Tuesday.

“This iceberg is sitting in a lake. They periodically break off the glacier. Each one is the size of a Costco!” Obama exclaimed.

The snapshots of a president in the early evening sun in front of a threatened glacier provided the lasting image Obama’s stage-crafters had planned for several months – a “signature” moment of his time in office, as one official put it.

RELATED: Photos from Obama’s Alaska trip

Along for the voyage with Obama, who was dressed in outdoorsman attire, were his national security adviser, Susan Rice, as well as his press secretary, Josh Earnest, and senior environmental adviser, Brian Deese. A park ranger chatted with Obama as he quietly absorbed his surroundings.

The roaring, high speed three-hour tour across the pristine blue waters of Resurrection Bay near the town of Seward brought the President within 50 yards of endangered Steller sea lions, whose population is only beginning to recover after decades of decline.

A National Park Service ranger accompanying reporters on the journey said the melting glaciers, combined with other non-climate factors, have impacted the sea lions’ diet.

“All of the wildlife that depend on this ecosystem are impacted by fresh water being put back into the ocean,” Ranger Colleen Kelly said.

Along the way, there were other brief moments that showcased the state’s ocean life. A porpoise and humpback whale were spotted nearby, dipping below the surface in a game of hide and seek with photographers.

“You’re allowed to say ‘thar she blows,’” a voice said over the boat’s loud speaker.

Before the boat tour, Obama insisted there are national security implications of global warming, pointing to Russia’s expanded military and commercial interests as the arctic melts and opens up new shipping channels.

In a brief statement to reporters, the President announced he is accelerating the construction of new Arctic Ocean icebreakers to try to keep up with Russia’s presence in the region.

RELATED: Obama wants new Coast Guard icebreakers in the arctic

“After World War Two, we had seven ice breakers and now we only have two. Russia has 40 and 11 more planned,” Obama said. “In light of the changes taking place, some of which (are) already happening and inevitable, it’s important we are prepared,” he added.

Earlier in the day Obama hiked to the edge of the aptly named Exit Glacier inside Kenai Fjords National Park. The glacier has slowly melted away over the last two centuries. But its retreat has accelerated in recent years, losing 1,000 feet of ice in the last 10 years.

Obama took note of the National Park Service signposts that mark the glacier’s steady decline by year. A “2005” sign stands where tourists could once touch the edge of the ice a decade ago. Then glacier has shrunk considerably since then. The latest marker, “2010,” now looms a few hundred feet from Exit’s nose.

“This is as good of a signpost of what we’re dealing with when it comes to climate change as just about anything,” Obama said, reiterating scientists’ concerns that the vanishing glaciers are contributing to sea rise along the nation’s coasts.

“We want to make sure that our grandkids can see this,” he added.

In an effort to spread that message younger audiences, Obama also taped a segment on global warming with reality TV star and survivalist Bear Grylls. The special is expected to air later this year.

RELATED: Obama to appear on NBC survival show with Bear Grylls

The presidential stop in Seward attracted hundreds of the town’s residents to various points along Obama’s itinerary, from the national park to a local fudge-maker. Obama posted highlights from the day on the White House Instagram account.

Randall and Christina Stauffer awaited Obama’s arrival in lawn chairs they set up just outside of the landing zone for the President’s helicopter.

“I didn’t have my driveway plowed one time last year,” Randall Stauffer said about the area’s warming winters.

The couple angrily accused Alaskan leaders of turning a blind eye to the issue of climate change out of fear of the state’s powerful oil and gas industry.

“It’s not cool to talk about climate change when you’re getting a check cut from the oil companies for you,” Christina Stauffer said.

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