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Obama seeks to cement climate change legacy

Over the next few days, President Barack Obama will tread gingerly on a receding glacier in the Alaskan Arctic.

Over the next few days, President Barack Obama will tread gingerly on a receding glacier in the Alaskan Arctic, talk to coastal villagers whose homes are threatened by eroding shorelines and salmon fishermen whose livelihoods are endangered — all in an aggressive and high profile effort to highlight the impact of global climate change.

The trip to the Alaskan Arctic — the first by a sitting president — is the culmination of an increasingly forceful climate change policy push over the past two years by the Obama administration.

Related: Obama announces new green energy initiatives in Las Vegas

The White House has honed in on climate change as a core policy priority with a domestic and international approach that has met with mixed response among both liberals and conservatives. This week alone he invoked the perils of climate change during visits to the National Clean Energy Summit in Las Vegas and New Orleans' storm ravaged Lower Ninth Ward to commemorate the tenth anniversary of Hurricane Katrina.

"No challenge poses a greater threat to our future than climate change," the president told a crowd in Las Vegas.

With these trips, along with his trek to Alaska where he will speak at a State Department-sponsored conference on the Arctic, Obama is attempting to set the stage for a major international climate change agreement he hopes will come from a summit in Paris in December.

That agreement could help secure his legacy as the first sitting president to address global climate change in a substantive way, environmental policy experts said.

"The president has from the beginning recognized that climate change is an existential challenge to the country and the world. It may be the issue that is the most important long-term issue of his presidency," said Paul Bledsoe, a former adviser to the Clinton White House on climate policy. "Future generations will look back at him as the first global leader to take decisive action on climate change."

The Obama administration's work of lifting the issue of climate change from the periphery to the fore began in a series of fits and starts.

As the nation struggled to recover from the worst economic climate since the Great Depression amid massive job losses and record home foreclosures, Congress debated the merits of "cap and trade" legislation aimed at rewarding companies that cut carbon emissions and raising the cost for those that don't.

It was an effort to make climate change resonate during an era when many Americans were more worried about pocket change.

"The administration had supported cap and trade before the economic crisis but the political climate was horrible, no getting around it," Bledsoe said. "His advocacy of climate change in the midst of the worst economic climate since the Great Depression hurt him significantly."

Ultimately, after much debate, the House passed a bill. The Senate refused to take it up.

And "cap and tax" became one of the key rallying cries during the rise of the Tea Party leading up to the Democrat's loss of the political majority in the House.

And though the president touted "green jobs" in his 2011 State of the Union address — the first after his party sustained major election losses — the connection to the urgency of addressing climate change didn't fully resonate, environmental policy experts said.

"The whole green jobs efforts was a response to (the economic downturn)," said John Byrne, director of the Center for Energy and Environmental Policy at the University of Delaware.

To the chagrin of environmental activists, the White House seemed to become less vocal on climate change as the administration regrouped and the president focused on re-election.

However, in his second term, Obama was back in full force on climate change.

In a 2013 speech at Georgetown University, Obama made the case for climate change by tying the science to a moral imperative for future generations.

And he wasn't going to wait for Congress to give him the okay.

"I refuse to condemn your generation and future generations to a planet that's beyond fixing," Obama said.

The next few years marked a dramatic resurgence in the administration's efforts, one largely advanced through executive actions.

"He has changed direction and is speaking much more clearly about the risk that we face," Byrne said. "The science has gotten a lot better and the confirming evidence is very strong."

Brian Deese, special assistant to the president and a senior advisor who deals with climate issues said in his second term, the president was determined to get more done.

The president's directive was "let's look creatively at all the tools that we have to try to move the ball forward," Deese said.

He pointed to perhaps the most significant action the president's taken yet, the first-ever national standards to cut carbon emissions from power plants.

The ambitious plan requires states, over the next 15 years, to cut carbon dioxide emissions by 32 percent compared to 2005 levels from power plants. The goal goes further than the 30 percent cut the administration called for last year.

Related: Climate activists gear up to fight for the planet's life

The revised plan also give states more time to comply.

"The regulatory approach is a better political means of dealing with the problem," Bledsoe said. "It's less in your face."

The issue is also an emotional one for the president, known for being cool and collected. He choked up at the end of his remarks announcing the clean power plan.

"I don't want my grandkids not to be able to swim in Hawaii, or not to be able to climb a mountain and see a glacier because we didn't do something about it," he told the audience. "I don't want millions of people's lives disrupted and this world more dangerous because we didn't do something about it. That would be shameful of us. This is our moment to get this right and leave something better for our kids."

Climate change is also a theme the White House has tried to weave into other policy conversations.

The impact of climate change on troop readiness and national defense was the focus of the president's remarks during a May commencement speech at the Coast Guard academy.

In June, the surgeon general talked about the impact on climate change on health.

And this April, the president spent Earth Day in the Everglades talking about how climate change was threatening Florida.

"If we don't act, there may not be an Everglades as we know it," President Obama said after touring the Everglades National Park.

But, for all the progress and promises, progressive groups and environmentalists are concerned about some of the president's plans.

Just weeks ago, Obama gave final approval to Shell Oil to drill in the Alaskan Arctic for the first time in 20 years.

Former Secretary of State and 2016 presidential candidate Hillary Clinton broke with the administration on the decision, Tweeting, "The Arctic is a unique treasure. Given what we know, it's not worth the risk of drilling."

And CREDO, a progressive group, released a video, using the administration's own pictures, to demonstrate what they've called "climate hypocrisy" even comparing the president's trip to Alaska to President George W. Bush declaring "Mission Accomplished" six weeks into his decade-long invasion of Iraq.

"I don't think the president is going to stand anywhere and say drill baby drill, but the message that he is sending is that we can have it both ways," said Elijah Zarlin, CREDO's climate campaigns director.

White House press secretary Josh Earnest pushed back, insisting the president "has imposed on the oil and gas industry some of the toughest, most stringent safety standards in history" and the need for drilling in the Arctic is needed as the country transitions to cleaner sources of energy.

"The president believes it's much smarter for the United States to rely on American oil and gas as opposed to relying on importing oil and gas from some of the most volatile countries and regions of the world," Earnest said.

And while Republican candidates like former Florida governor Jeb Bush have voiced their support for drilling, they've taken issue with the way the Obama administration has advanced its environmental agenda, without legislation. Bush called the clean power plan "irresponsible and overreaching" and Texas Senator Ted Cruz called it "lawless and radical".

Meantime, the Obama administration is pressing on to lay the groundwork for Paris, checking a huge box last year by securing an agreement with China to cut carbon emissions drastically by 2030 and a deal with Brazil to increase renewable energy production.

Environmental policy experts stress that the U.S had to take drastic steps domestically to be able to go forward and legitimately argue internationally for policies to address climate change.

All of this will add weight to the president's efforts to hammer out a global climate change agreement during the summit in Paris in December.

"It put some real juice in these talks," said David Doniger, director of the climate and clean air program for the Natural Resources Defense Council."

But, it's not clear just how many countries will commit to significant cuts in carbon this December and the administration is trying to keep expectations in check.

"I think that we are well positioned as a result of the progress we've made to get a global agreement this year, there's a lot of work yet to be done," Deese told NBC News, "but we have a lot of tools in place and we're going to keep using those tools aggressively between now and then."

This story originally appeared on NBCNews.com