Julia Wolfe’s latest in a series of increasingly political, oratorio-like works, “unEarth,” premieres this week at the New York Philharmonic.Julia Wolfe, the Pulitzer Prize-winning composer and co-founder of Bang on a Can, has a way with words.In “Anthracite Fields,” the coal-dark highlight of a series of folklike, oratorio-adjacent works in which Wolfe, 64, has been putting American injustices under her unsparing sonic microscope, she lists the men named John with single-syllable surnames who can be found on an index of Pennsylvania mining accidents — a litany hundreds of Johns long.Her memorial to the Triangle Shirtwaist Factory disaster, “Fire in my mouth,” concludes with an ethereal incantation of the 146 workers who died, their names drifting in sound, as if into the smoke of history. “Her Story,” a reflection on women’s rights, quotes some of the choicest insults that were spat at suffragists a century ago, as if to ask whether they sound familiar today.Now comes “unEarth,” a confrontation with climate change that premieres on Thursday at the New York Philharmonic, with Jaap van Zweden leading the soprano Else Torp, the men of the Crossing and the Young People’s Chorus of New York City, in a staging by the director Anne Kauffman. It starts, and ends, with words sung by the children who helped write them.Wolfe’s “Fire in my mouth” at David Geffen Hall in 2019.Caitlin Ochs for The New York Times“Of course, it’s so important for everyone but particularly poignant for younger people,” Wolfe said of the climate crisis in a recent interview. “A lot of the leadership right now, a lot of the feisty leadership is coming from young people, particularly from young women.”The texts that Wolfe uses in “unEarth” have a sense of literary adventure familiar from her earlier oratorios. She read widely to research it, and noted the influence of such writers as Sami Grover, Peter Wohlleben and Elizabeth Kolbert, a friend. The libretto draws on Emily Dickinson and the book of Genesis; in the second movement of three, “Forest,” the word tree is translated into myriad languages, which she pounds into a celebration of all things arboreal, backed by conga drums.“She is always taking kernels of text that have a lot of resonance in the stories of the world we live in,” Donald Nally, the conductor of the Crossing, said of Wolfe. “Honestly, at some point, you start to stop thinking about the words and you drift off into larger ideas.”Many of Wolfe’s compositions — another, an orchestral work called “Pretty,” will premiere at the Berlin Philharmonic next week, under its chief conductor, Kirill Petrenko, a Wolfe admirer — have had political themes. But the larger ideas of “unEarth” are more directly delivered than those of any of her other socially conscious but primarily historical oratorios, dating back to “Steel Hammer” more than a decade ago.The impulse to speak plainly comes not just from the subject matter, but from Wolfe’s chosen collaborators. When she decided to involve the Young People’s Chorus in the work, as she had in “Fire,” she sought the input of its singers; she and Kauffman asked its conductors to lead the choristers in discussions about the climate crisis, and recorded them.“Something that I remember is everybody agreeing on this sense of urgency,” Ryoko Leyh, 16, said of the conversations she took part in. “Everybody was saying something like ‘I’m scared,’ or ‘I’m always thinking about it, it’s always on my mind and making me anxious.’ So I feel like we all had different ideas of what is actually going on and what we can do to stop climate change, but we all had that collective sense of dread.”The children of the chorus come from all kinds of educational backgrounds, said Francisco J. Núñez, its artistic director. For many of them, the discussions were a learning opportunity; some were as young as 8.“It really made me think on how impactful learning about climate change and global warming itself can be on the young population,” Irene Cunto, 12, said, “because at the end, we’ll be the ones that’s facing it.”Wolfe’s works in this vein have grown increasingly political. “I can be poetic, poetic, poetic,” she said, “but then at a certain point it’s like, what are we doing here?”Amrita Stuetzle for The New York TimesThe process was instructive for Wolfe, too. She was amazed at the subtlety of the conversations, and decided to use parts of them in the piece. It begins with a quotation of one of the most junior participants, who saw global warming as “like a monster devouring the Earth.” The work ends with another quotation, this time of an older singer, as their phrase “hope requires action” is chanted like a mantra, before the chorus and the soprano demand that the audience “act,” with an insistent, if fearful and minor-key, final crescendo.“We just feel powerless because of this idea that we’ve inherited all these problems and now it’s our responsibility to fix everything,” Leyh said, pointing to the importance of the chorus singing words its members have written themselves. “It’s like we’re being given a platform that we don’t usually have, literally, to say what we want to say in a way that we know is going to be heard.”Making the Young People’s Chorus the voice of hope in “unEarth,” and ensuring that the audience would have to look at them “in the face,” as Wolfe put it, offered the composer something of a way through the dilemmas involved in creating explicitly political art, a challenge that climate-conscious composers are finding becomes more acute as catastrophes grow. Wolfe said that she was trying not to be too didactic, but that she was content with her solution in the final movement, “Fix It,” which lists a number of ways in which individuals can make a difference — Meatless Mondays, No Mow May — as well as broader policy concepts, like “reforestation” and “solarification.”“I can be poetic, poetic, poetic,” Wolfe said, “but then at a certain point it’s like, what are we doing here?”The Philharmonic commissioned “unEarth” after the success of “Fire in my mouth” four years ago, and is presenting it on the first of two programs that make up “Earth,” a climate mini-festival. The second program, next week, includes the belated local premiere of John Luther Adams’s “Become Desert,” which debuted in Seattle five years ago.“In the end, music is about emotion,” said Deborah Borda, the president and chief executive of the Philharmonic, “and Julia is able to combine, in that way that we cannot quite explain, a combination of beauty and emotion. It carries an even stronger message as a result.”Each of Wolfe’s oratorios has offered a different answer to the question of where the balance of poetry and politics lies, though she sees a progression through them. “Anthracite Fields” was not exactly shy about its views — it sets a speech by John L. Lewis, the militant leader of the United Mine Workers — but, as one listener pointed out to her, it does not explicitly mention protest. “Fire,” partly as a consequence, has an entire, thumping movement called “Protest.” “Her Story” is more of an inquiry into change than an indictment of the past, but as Wolfe put it, “it’s a little sassier.”“UnEarth,” though, includes lines like “the house is on fire,” and “clean up your corporation.” It goes further, and with good reason.“The others were more reflective. ‘Who were we?’ ‘Who are we?’” Wolfe said. “And this is like: ‘Guess what. We have to do something.’” More