By Roberta Rampton

WASHINGTON (Reuters) - When President Barack Obama sets out this week to meet world leaders in China and Laos during his final presidential trip to Asia, he will make an unusual stop along the way.

With time running out for more action on climate change during his time in office, Obama will drop in to Midway Atoll, a far-flung and largely uninhabited coral reef that is a refuge for sharks, albatrosses and endangered turtles and seals.

The photo-rich stop is aimed at both raising awareness about the threat posed by climate change, and showcasing Obama's decision to protect a larger part of the ocean around Hawaii.

But the trip to the middle of the Pacific Ocean will also highlight the high stakes of climate change just before Obama meets world leaders in China.

"I think it's going to be an amazing sequence, and one that really matters," said Doug McCauley, a conservation biologist from University of California, Santa Barbara.

"Suddenly, you're sitting in a room with the leaders who will decide what the fate of that place is going to be," McCauley said.

The rare trip is both a signal of the importance Obama gives to climate change - and a sign of his focus in bliateral meetings with Chinese President Xi Jinping.

The two leaders have clashed on economic and security issues, but forged common ground on climate, which helped secure a global deal to cut carbon emissions at a Paris conference last year.

"We have to recognize that climate change and clean energy cooperation has really helped to create better overall stability in the U.S.-China relationship, writ large," said Andrew Light, a former senior climate official in Obama's State Department.

Light, now with the World Resources Institute think tank, said he expects Xi and Obama will try to push other G20 leaders to agree to timelines for implementing the Paris agreement and work on cutting other greenhouse gases like methane and hydrofluorocarbons.

Any progress on climate issues could be a rare bright spot in a trip otherwise dominated by concerns about the international economy, anti-globalization sentiments and global security problems.

With less than five months left in the White House, Obama is racing to cement his record through actions he can take without help from the gridlocked U.S. Congress.

For example, at Obama's final meeting with his Canadian and Mexican counterparts, the leaders set new goals for clean energy production.

Republicans in Congress have thwarted Obama's legislative efforts on climate, and mocked him for his focus on an issue they see as less pressing than the economy and defense.

Obama also has faced criticism from environmental groups for not doing more to limit U.S. oil and gas production.

"If we're going address the climate crisis or meet our climate commitments, the vast, vast majority of fossil fuels need to remain in the ground," said Brendan Cummings, conservation director with the Center for Biological Diversity.

But former Environmental Protection Agency director Carol Browner said Obama has done what he could on climate both through leadership on the international stage, and by using existing laws to kick-start the clean energy sector and cut emissions from vehicles and power plants.

"Nobody should ever be disappointed with this president on climate change," said Browner, who led the White House climate push in Obama's first term.

(Editing by Alistair Bell)