Katowice, Poland (CNN) Think of them as the Justice League for global warming diplomacy. They're the "High Ambition Coalition" and they arrived late this week at the beleaguered COP24 climate talks here in Polish coal country, wearing suits and hosting press conferences -- hoping to salvage a United Nations treaty that is meant to save the earth.
Dozens of reporters from around the world shoved into a tiny, sweaty conference room Wednesday night hoping to hear what the coalition had to say about the negotiation taking place the talks, which were described by one scientist as a "huge mess."
The UN's secretary general gave a speech earlier in the day saying it would be "suicidal" to fail. Meanwhile, the United States, Saudi Arabia, Russia and Kuwait are questioning the basic premise underling the talks -- that 1.5 degrees of warming would cause global calamity. To avoid that, global carbon pollution from fossil fuels and other sources would have to be cut in half in only about a decade, according to the latest report from the intergovernmental panel on climate change.
It's a massive undertaking. The kind that tends to attract superheroes.
At the front of the room, flanked by ministers from Europe and Latin America, was David Paul, the environment minister from the Republic of the Marshall Islands. Never heard of it? A pin on Paul's coat lapel, shaped like the nation's flag, offered clues about the place. The flag is a field of blue slashed with thin lines of white and tan. The blue represents the ocean -- which is most of the Marshall Islands' territory. It's been called a "big ocean country" in the Pacific, and if warming is allowed to continue apace, scientists say the nation may not exist in coming decades. Its low-lying islands could sink beneath rising seas.
Paul came to Wednesday's meeting with a clear demand: Finalize the rules that will govern the Paris Agreement, which is meant to avoid the level of warming that could sink the Marshall Islands and kill the world's coral, supercharge storms, intensify droughts and so on.
Paul is fighting for the survival of his nation, while the coalition -- made up of more than 20 members, from countries rich and poor, big and small -- are fighting for the survival of the planet.
The message: Warming must be limited to 1.5 degrees Celsius and there must be strong, clear rules on reporting and cutting pollution.
The demands were a "shot of energy" at a critical moment in the negotiations, said Jake Schmidt, international program director of the Natural Resources Defense Council.
"We finally have a growing group of countries signaling that they want to leave here with a strong agreement that delivers on the promise of Paris," Schmidt said.
The members of the coalition express almost unyielding optimism about what is seen by many experts and environmentalists as a hopelessly slow and dysfunctional process.
Leaving the press conference, I stopped Miguel Arias Cañete, the European Union's climate commissioner and asked: Can you do this -- save the talks -- without the help of the United States, given that President Trump has denied the reality of climate science and pledged to pull out of this agreement?
"America is in," he said, not missing a beat. "The federal government is on climate holidays. But in the United States, there is action. California. Governor Brown. The mayors of the important cities. The governors. There's action. Civil society is alive in the United States."
The optimism could be seen as justified by the coalition's origin story.
The High Ambition Coalition emerged at the COP21 climate talks in Paris in 2015. That's where world leaders agreed to the treaty that's being put into practice now, with Paul's predecessor from the Marshall Islands, Tony de Brum, at the center. He rallied with the United States and other world powers to make a moral call for action that became the Paris Agreement.
Before those talks, the idea of a 1.5-degree temperature limit for warming was not on the table. De Brum and the coalition made that level of ambition seem achievable.
But much has changed in the three years since Paris. The science has gotten scarier.
In October, the Intergovernmental Panel on Climate Change issued a report saying the difference between 1.5 and 2 degrees of warming could be catastrophic. Currently the world is on track to warm more than 3 degrees.
In 2015, the pollution from fossil fuels that drives climate change appeared to be leveling off, a sign that emissions might drop in coming year. But now those CO2 pollution levels are up considerably, driven largely by the burning of dirty coal according to a report from the Global Carbon Project.
"Two years ago, we and others were saying it looks like CO2 emissions are flattening off and polices are working -- but not going fast enough," said Bill Hare, a climate scientist and physicist who is director of Climate Analytics, a non-profit focusing on climate science and policy. "Now we are seeing it's actually going in the opposite direction, which is just astonishing, really, given the scientific evidence is just accumulating."
The politics are almost unrecognizable.
In 2015, the Obama Administration in the United States led the conversation on swift action with China. Under President Trump, the United States on Saturday joined Saudi Arabia, Russia and Kuwait to decline on "welcoming" the latest science. That move, according to observers, has flared emotions among delegates from some of the world's poorer countries, who face dangerous consequences for a problem they haven't caused.
There's been tragedy in the Marshall Islands as well. Minister de Brum, who helped form the High Ambition Coalition and emerged as the moral voice of the Paris Agreement, died in October 2017. Obituaries heralded him as one of the heroes of those negotiations.
"Tony de Brum is a great statesman, and his are huge shoes to fill," said Paul, the current minister. "He really created something special that galvanized the entire world."
In an interview on Thursday, Paul said he feels the weight of that story on him as he walks these conference center halls this week. He also thinks about his children, ages 7, 8 and 15.
"We have 12 years to reverse these trends," he said, citing a date from the latest IPCC scientific report, which shows preventing 1.5 degrees of warming above pre-industrial levels could soon become impossible. Paul flipped that statement to glass-half-full, though. "We have that window of opportunity," he said." We have to take advantage of it."
"A half degree makes a huge difference in terms of the state of our islands," he said. "This is really about the existence of our country -- and our culture and our people.
"The moment to act is now."