MIDWAY ATOLL (Reuters) - President Barack Obama snorkeled on Thursday in the electric-blue water off Midway Atoll, a remote coral reef that serves as a reminder of both modern global climate challenges and the United State’s dominance in the Pacific since its World War Two victory there.

The journey was aimed at sending a message about the need to protect vulnerable species and spaces from the ravages of climate change.

But it was also timed as Obama makes his way to meet Chinese President Xi Jinping and other world leaders in his last visit to Asia, having sought to refocus U.S. defense and trade policy on the region.

“It’s a signal, it’s a message saying the United States is committed to staying in the Pacific, and not sort of backing away,” said naval historian Tom Hone, who has studied the Battle of Midway.

Zipping around the island in an 18-golf-cart motorcade filled with Secret Service, aides and camera crews, Obama stopped to see several endangered green sea turtles lazily paddle in to bask on the white sand beach.

“When I grew up, we’d see these turtles all the time. You almost never see them beaching like this, just basking in the sun,” said Obama, who grew up in Hawaii, more than 1,100 nautical miles to the southeast.

Obama, whose presidency comes to an end in five months, has tried to use his time in office to make Americans more passionate about climate change.

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Less than 5 percent of American voters say the environment is the most important issue facing the country, according to Reuters/Ipsos polling between July 24 and Aug. 21, and 35 percent say climate change will not affect the way they vote in the Nov. 8 election to pick Obama’s successor.

The island visit bookends Obama’s trip last year to Alaska, where he hiked on a shrinking glacier.

“These aren’t ‘photo ops’ - I think these are real opportunities to help the American people understand,” said Carol Browner, a former head of the Environmental Protection Agency who advised Obama on climate issues in his first term.

“He can get a level of attention that nobody else can get,” Browner said.

Last week, Obama quadrupled the size of Papahānaumokuākea Marine National Monument to create the world’s largest marine monument, protecting the area off the coast of Hawaii from commercial fishing and drilling.

“This is going to be a precious resource for generations to come,” said Obama, his dress shirt undone an extra button in the sauna-like heat.

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“This is hallowed ground,” he said near a beach where young soldiers hunkered down under pillboxes, awaiting Japanese fighter planes during the World War Two Battle of Midway, one of the most-studied battles in military history.

“Had it not been for the courage and the bravery of those airmen, we might have not seen the tide turn in the battle of the Pacific,” he said.

In June 1942, U.S. forces, tipped by code-breakers that the Japanese navy was planning an attack, sank four Japanese aircraft carriers and a heavy cruiser in a giant air and sea battle.

Obama’s golf cart motorcade bumped over a tarmac pock-marked by shrapnel from the battle, passing old hangars and a “bone yard” of scrap metal, old office chairs, and broken appliances.

Massive bags held some of the 20 tons of plastic ocean garbage that land on the island each year, 5 tons of which come from the bellies of albatrosses, which feed the plastic to their young, often fatally.

Curious tern fledglings checked out his entourage, which tripled the island’s average population of about 35 humans.

“Watch the burrow!” called Miel Corbett, a Fish and Wildlife Services spokeswoman, as a visitor narrowly avoided stomping the underground home of the bonin petrel. About a million of the birds swoop out of their nests each night at dusk.

Vestiges of the island’s former life as a large naval base remain, although many have fallen into decay. Visitors have not been allowed since 2012 because of tight budgets. Reporters wrote their stories in a still-working 1970s bowling alley, just down the way from barber shop.