Nearly 200 countries are attending the Paris climate summit and nearly every one has something at stake. Yet it's hard to find anyone with more on the line than Tony de Brum, the foreign minister for the Marshall Islands.
"The Marshall Islands covers an area of approximately a million square miles of ocean. Many people call us a small island state. I prefer to be called a large ocean state," de Brum says.
The islands sit in the Pacific, far west of Hawaii, with a population of more than 70,000 spread over 29 atolls. I wanted to experience a day in the life of this United Nations summit through his eyes.
We're in the back seat of a car, rolling from his hotel through the dark and empty streets of Paris. It's before dawn and de Brum is getting his first briefing of the day.
"Every day has been like a 6:45 to midnight run," he says.
An aide continues the briefing, preparing the minister for a breakfast featuring former Vice President Al Gore.
"For us, it's 1.5 to stay alive," the aide says.
That phrase comes up a lot when you talk to people from small island states. Here's what it means:
The world's countries have agreed that if the global temperature increases by more than 2 degrees Celsius (3.6 degrees Fahrenheit), it will have disastrous impacts.
But in places like the Marshall Islands, de Brum says, even 2 degrees is a calamity. So the target it advocates is 1.5 degrees Celsius (2.7 Fahrenheit).
"We cannot be expected to sign off on a small island death warrant here in Paris," says de Brum. "Anything over 2 degrees is a death warrant for us. It means the sea level will rise above ... our level of the islands. It means the islands go under."
An 18-year-old named Selina Leem is riding in the car with us.
She's part of the Marshall Islands delegation, and she says things have already changed on the islands since she was a kid.
"The area that I'm living in, it's one of the most affected areas in the Marshall Islands," she says.
Coconut trees she used to climb have washed away. Sea walls have been demolished.
"Graves of grandparents, people who lived in my town, are just gone," she says. She worries that her family may have to leave their home.
"We live close to the water. Last year there was an inundation, and for the first time the water actually washed into our house," she says.
The sky is just starting to turn pink by the time we arrive at the conference center. The minister wears a bright red scarf over his dark suit and silver hair. His skin has the wear of a man who's spent much of his life in the sun.
De Brum ducks into the breakfast with Al Gore and other delegates. Reporters are not allowed in. The next event on his schedule is a bit ... creamier.
"We're about to go to a launching of a new flavor of Ben & Jerry's ice cream," he says.
The flavor is called Save Our Swirled.
De Brum breaks into song, to the tune of Duke of Earl. "Scoop, scoop scoop, scoop of swirl, swirl, swirl ..."
This will not be the last time today he sings the song.
At the event, there's a giant ice cream cone with a melting globe on top of it. A scrum of reporters with cameras crowds around the ice cream stand. The CEO of Ben & Jerry's, Jostein Solheim, welcomes de Brum.
It's a strange thing about these climate summits. The fate of humanity might hang in the balance, but there can also be a kind of circus atmosphere.
From the ice cream photo-op, the foreign minister walks to one meeting after another. A round of closed-door deliberations takes up his entire afternoon, and into the evening.
The U.S. has a complicated history with the Marshall Islands. The American military tested nuclear weapons there. Today, Marshallese people who want to relocate to the U.S. are allowed to do so.
De Brum says it's not so simple though.
"To move people from their islands, it's not like New York to California," he says. "It's a serious, traumatic, heart-wrenching separation of a man from his soul."
De Brum, who is 70, has 10 grandkids and four great-grandchildren, most of whom live on the islands.
As he walks from one meeting to another, I ask him if the younger generations will be able to remain.
"I'm hoping that what I do here will result in them not having to move anywhere. That's the whole purpose of the exercise, isn't it?" he says. "I Skyped with them last night. 'How's it going? Do we have to move anywhere?' I said, 'No, not yet.'"
And with that, the foreign minister for the Marshall Islands heads into one more meeting.