The cavalcade of models — including familiar face Agyness Deyn — all had white paint heaped on their hair, and walked in airy looks that came in waves according to color. 

"The colors were so beautiful," Mr. McGinley told The Observer after the show. He agreed with us about the sci-fi feel of some of the clothes, which was set up by the foreboding balloon structure. "There were some pieces that kind of reminded me of Blade Runner that I liked."

But perhaps the accentuating detail that made the strongest impression was the music: a churning series of start-stop blippy and booming dub that would attack over and over again. Memorable, to be sure, though polarizing may be the better way to describe it. So we talked to M.I.A., sonic provocateur par excellence, about what she thought of the soundtrack.

"It just seemed like a Die Antwoord CD on repeat, yeah, with a bit of dubstep thrown in," Maya told us in her thick English accent. "But it was interesting. It's definitely juxtaposed with what the style of the clothing was. It was a good contradiction, I thought."

Suffice it to say that Alexander Wang makes sure the music at his show — much like the show itself — brings something different to the table. 

A few minutes later, Mr. Bronfman, 27—son of the billionaire Warner Music CEO and Seagram liquor fortune heir Edgar Bronfman Jr., and fiancé of the Grammy-nominated electro–hip-hop auteur M.I.A.—was mingling with power players of the environmental movement. 

There was Kevin Conrad, best known as the guy who famously told the United States, “If you’re not willing to lead … please get out of the way,” at the U.N.’s 2007 Climate Change Conference in Bali; Graciela Chichilnisky, the feisty Columbia University economist who helped get the Kyoto Protocol adopted in 1997 by introducing a marketplace for nations to trade carbon emission rights; and fellow Columbia professor Peter Eisenberger, a physicist who’s working with Ms. Chichilnisky to develop a technology that can suck noxious emissions right out of the air.

“It’s really amazing stuff,” said Mr. Bronfman, who learned about their efforts two years ago through Ms. Chichilnisky, his childhood neighbor. He convinced his father to invest in the duo’s technology firm, Global Thermostat, where he has been named associate managing director (Edgar Bronfman Jr. is the chair), and is headed to Copenhagen with them in a few weeks. 

During the event, Mr. Bronfman, tall and scruffy-faced in a slim black suit, dark maroon button-down (no tie) and black canvas sneakers, sat near his mother, Sherry Brewer Bronfman, and his sister, Vanessa Bronfman, both bubbly as they munched on their respective salmon and chicken entrees. He speaks softly and has sleepy eyes and a laid-back demeanor, even though he always seems to be rushing around. After lunch, he declined a cocktail.

“I have to go meet my pops,” he said.

DESPITE COMING FROM one of the wealthiest families in New York, if not the U.S. (Forbes recently ranked his grandfather, Edgar M. Bronfman, No. 123 on its 2009 list of the 400 richest Americans), Ben Bronfman has managed to remain relatively obscure throughout most of his adult life. He was raised on the Upper West Side and attended the Collegiate School. He discovered punk rock in the mid-1990s and frequented all the grimy downtown spots of the day—Coney Island High; ABC No Rio; the cube at Astor Place. After a year at Emerson College studying politics and law, he spent the first half of his 20s touring basements, bars and V.F.W. halls with a band called the Exit, in which he played guitar and sang. (His new band is called Bermuda). He went by his mother’s maiden name at the time. “It wasn’t the Strokes. It wasn’t a bunch of posh kids. It wasn’t New York City private school. That’s not who we were,” he told The Observer recently. “And I didn’t want every article on us to be about,” he paused, “my father.” Mr. Bronfman is a curious kind of scion: not dutiful, not a rebel, but something in between.

In May of 2008, news broke that M.I.A.—real name: Maya Arulpragasam—a Bed Stuy–dwelling, Sri Lankan (by way of Britain) singer and visual artist famous for her genre-bending music, anti-establishment politics and eccentric style, was recently engaged to “Benjamin Brewer,” a young member of the Bronfman clan. (It’s an unlikely union, to be sure; he the son of Manhattan society, she the daughter of Sri Lanka’s oppressed Tamil minority.) Headlines followed in October that the couple was expecting a child. He was born on Feb. 11, three days after they walked the red carpet at the 51st Grammy Awards, where a full-bellied Ms. Arulpragasam performed with Kanye West and Jay-Z.

In March, the tabloids gawked over the newborn’s purported name, prompting Ms. Arulpragasam to declare on her MySpace page:

MY BABY IS NOT CALLED ICKITT, PICKIT OR LICKIT THANK YOU VERY MUCH TO ALL THE HOLLYWOOD PRESS. HES A BABY , HE DONT NEED PRESS!

(Shortly thereafter, TMZ got a hold of the birth certificate, revealing the child’s real name, pronounced “I-Kid,” as in, Ikhyd Edgar Arular Bronfman.)

“I try not to let any of that stuff penetrate my sphere of consciousness,” said Mr. Bronfman on a crisp October evening, a few days after a French court ruled that his father would stand trial in Paris on insider-trading charges. He was sitting on the edge of a wicker couch in the dim light of the Bowery Hotel Bar’s back patio with a glass of Malbec and a Winston. Ms. Arulpragasam was across town doing a photo shoot for Vogue. 

“If you grew up in New York counterculture, I think it’s relatively easy to filter out all the bullshit,” he continued. “And Maya does such a good job keeping her ship on an intellectual level, keeping it really culture- and art-driven. So I just try not to let it drift too far from shore.”

Their love affair began in December 2007, a few days before New Year’s.

“We met at our mate Simonez’s house on the Lower East Side,” said Mr. Bronfman. “He was a door guy at the Beatrice, I was going there all the time, and he knew Maya from her art school days at Central St. Martin’s in London.”

Mr. Bronfman proposed four months later in San Francisco. He said that ever since “the little one” was born, they’ve been hopping back and forth between their apartments in L.A. and Bed Stuy.

“It’s the best thing in the world,” he said of fatherhood. “I have a whole new crazy profound respect for my parents. I find my conversations are more direct. I think it makes you just—it turns you into a man, you know? It makes you real.”

Mr. Bronfman didn’t care to elaborate on his relationship with Ms. Arulpragasam, who is 34. But what about the wedding? “We’re working on it,” he said. “We haven’t picked an exact date, but it will probably be pretty soon. In New York.”

Ms. Arulpragasam could not be reached for an interview, but told Spin last year: “I’ve always had that fuck-the-system mentality, and his dad is so ‘the system.’ But then, they’re the most liberal family—they bootlegged alcohol, for God’s sake. They’re rich because they threw big, illegal parties, so I don’t mind.”

A FEW YEARS  ago, Mr. Bronfman found himself getting depressed about the doom and gloom of climate change.

“We hadn’t talked in a long time, and I remember getting a voice mail from him just being like, ‘I’m starting to understand what’s going on with global warming and it’s really freaking me out!” said Billy Parish, founder of the Energy Action Coalition and Mr. Bronfman’s classmate at Collegiate.

The two friends met up one day for a walk around the Central Park Reservoir. “I felt like the greater environmental picture was always marketed more toward, like, the Dave Matthews crowd,” Mr. Bronfman said. “So I just said to him, ‘What if we could bridge the gap between quote-unquote hipster culture and the environment?’”

The result was Green Owl, an indie record company described on VanityFair.com last year as “Earth’s first green music label.” It focuses on digital releases, sheathes its physical products in 100 percent post-consumer recycled paper, and buys carbon credits to offset its energy use. It has signed four bands to date, including Brooklyn’s the So So Glos and African pop sensation the Very Best. 

Mr. Bronfman and his partners are expanding the Green Owl brand into a news and entertainment Web site and sustainable clothing line, which will be overseen by Mr. Bronfman’s younger sister, Hannah. (He said a recent Page Six report that Hannah would be appearing in Tinsely Mortimer's upcoming reality show was inaccurate.) His older sister, Vanessa, is developing an online talk show to be hosted by their mother, a cultural philanthropist and former actress. (Ben is proud of his interracial roots: Sherry, who is African-American, and Edgar Jr. met through Dionne Warwick in the late ’70s, but divorced in 1991.) His father is on Green Owl’s board.

“It’s a family affair at this point,” said Stephen Glicken, general manager and co-founder.

Back at the Bowery Hotel, Mr. Bronfman opened his silver Mac and pulled up a grainy photograph of himself and Bill Clinton. “The picture’s from my dad’s BlackBerry, so the quality’s kind of shitty,” he said.

They’d met with Mr. Clinton the previous week at the former president’s Harlem offices to explain Global Thermostat’s carbon-capture technology (picture a power plant with a giant, 50-foot window that uses the plant’s excess energy to suck carbon from the atmosphere) and to show him a prototype of the company’s Web site, which the younger Bronfman is building.

“Right now, if I just said, ‘I’m gonna stop everything, stop all imports and exports, shut down all the grids, make us live in complete darkness,’ we’d still be dealing with the same amount of carbon that was emitted today for the next hundred years,” Mr. Bronfman said. “So you’ve gotta be able to stop it, catch it and pull it all the way back. We think we’ve found a way to do that.”

“Ben can move swiftly between beautiful rock music and highly technical concepts,” said Ms. Chichilnisky, who Mr. Bronfman will be assisting at the Copenhagen talks. She added of her protégé’s fiancée: “Maya’s a real sweetheart. She has a message that’s more than music. I think what they represent is unstoppable.”

jpompeo@observer.com