To most people, spoiled milk does not present a lot of possibilities. But most people are not Gal Yakobovitch, 27, who can look at a dairy’s worth of spoiled milk and see a fashion opportunity.

That opportunity was a recent project Yakobovitch undertook with Shaggy Coos, a Connecticut dairy farm. Yakobovitch, who is from Israel and graduated from Parsons School of Design in 2018, said that casein, a protein in milk, which is more easily isolated when the milk has begun to curdle, was once used to make hard plastic. Those properties led her to the idea of making a natural water-resistant rubber from the protein, by purifying the milk and then melting the casein into a rubber-like substance. She then used it to turn upcycled cotton T-shirts into biodegradable, made-to-measure workwear for the dairy’s employees. Nothing is wasted; the natural components can return to nature; the workers have clothes directly suited to their needs. It’s a closed system—the holy grail of sustainable fashion.

In her work, Yakobovitch said in a recent phone call, sustainability “is the only thing that’s important now.”

She’s not alone. Her generation of designers, many of them being trained in the top fashion schools, are rethinking what luxury, fashion, and design mean in a world confronting the climate crisis. In an earlier age, these students might have imagined themselves as the next Marc Jacobs—a Parsons alum, eponymous brand(s), creative director of a major design house—but now the goals are different. They might start their own brand, or go work or consult for a bigger one, but without fashion-world domination in mind—mass production and economies of scale aren’t exactly environmentally friendly. Instead, they bring new ideas that challenge what the industry represents, ideas that will radically alter not only how clothing is made and marketed but what your wardrobe might say about what you believe in. Hopefully the clothes will still look cool, but fads might become less essential. In a world wracked by climate change and increasingly skeptical about capitalism’s costs, ethics are more on trend. If clothes make the man, these students are asking, what do they say about the man who makes the clothes?

In an earlier age, these students might have imagined themselves as the next Marc Jacobs. Now the goals are different.

For Yakobovitch and her peers, sustainability isn’t defined only by organic cotton or recycled polyester, which fashion brands have often used as signposts to attract buyers who are thinking (or claiming to think) about sustainability. To them, the term “sustainability” itself has lost some of its power through “greenwashing” (wishy-washy or false claims about a product’s environmental friendliness).

Gal Yakobovitch, who graduated from Parsons School of Design in 2018, says sustainability “is the only thing that’s important now.”

To think of its inverse—unsustainability—as something that literally cannot be sustained may help explain why, for them, new fashion must go further. “You can’t just take the model that’s worked before and make it organic,” said Matthew Needham, 26, a designer and master’s student at Central Saint Martins, in London. “That might work for five years, but it won’t work longer than that. People who buy things aren’t stupid—they want to know the truth of where things come from and who made it.”

For Yakobovitch and Needham, like many other young fashion designers and students, there should be no other way to make clothing: complete transparency in the supply chain; ideological opposition to mass production; upcycling; information sharing; biodegradability; awareness of an item’s life cycle; the responsibility of brands to repair the clothes they sell; community-specific clothing; retreating from the season-based fashion calendar.

Each of those tenets puts these next-generation designers somewhat at odds with much of the global fashion industry, which has been slow to address and, sometimes, even acknowledge its impacts on the environment in a time of climate crisis.

It’s easy, maybe, to understand the problematic impact of fast fashion: mass-produced clothing, created primarily from synthetic fibers (spun from fossil fuels), not made to last, all on a continuous production cycle. Less well understood, and often not even known, are the environmental impacts of most clothing production—water use, water pollution, deforestation, desertification, microplastic-fiber pollution, and on and on. It probably shouldn’t be surprising, given that fashion touches so many different industries: agriculture, livestock, forestry, mining, petrochemicals, waste, shipping, among others. And yet it’s a set of issues that brands and consumers have been willing to overlook.

The global fashion industry has been slow to acknowledge its impacts on the environment.

That is starting to change. Gucci, in addition to putting on a carbon-neutral runway show last fall, has announced that it is now carbon-neutral throughout its supply chain, which it achieved mainly by offsetting, a practice where carbon emissions are “offset,” often by the planting of trees, which absorb carbon dioxide. Sustainability advocates say that carbon offsetting is a step in the right direction, but it is not a long-term solution, which Marco Bizzarri, the president and C.E.O. of Gucci, has acknowledged. (Though, he maintains, it’s better than nothing). Like Gucci, Macy’s and Bloomingdale’s have announced they would be fur-free by 2021. (Queen Elizabeth will also not buy any new fur.) After a good amount of negative publicity, Burberry announced it would stop destroying unsold merchandise; the company has also stopped using fur, is committed to carbon neutrality by 2022, and is working to phase harmful chemicals out of its production process.

Matthew Needham, a student at Central Saint Martins, makes fashion out of environmental waste, fly-tipped rubbish, and upcycled luxury-fashion deadstock.

Many of these changes are coming in response to pressure from consumers, especially younger shoppers, or in response to undesirable attention, like the Extinction Rebellion protests outside London Fashion Week. Some industry leaders, however, are less sanguine about the changes afoot: the C.E.O. of H&M said that the youth climate movement’s “shaming” of consumption and growth “may lead to a small environmental impact, but it will have terrible social consequences.” Perhaps not surprisingly, H&M reported $4.3 billion of unsold clothes last year.

Most organizations advocating for reform in the industry readily admit that patterns of consumption have to change: Bronwyn Seier, a content coordinator and designer for Fashion Revolution, wrote in an e-mail that our habits are part of the problem: “Our desire to consume is so closely connected to our desire to improve ourselves by refining our image,” but “sustainability requires that we bury the hatchet with our insecurities and find new ways to satisfy the desire to reinvent ourselves.

“So long as we believe that a shiny new pair of jeans will make us desirable, fashion’s hyper-consumption model will prevail.” Especially if we’re lead to believe that we’ll need a shiny new pair of jeans in a slightly different shape next year.

“Sustainability requires that we bury the hatchet with our insecurities.”

The approach among young designers is decidedly different. Boy Kloves, a 24-year-old fashion student at Central Saint Martins, said that while he appreciates that some of these bigger brands are listening to what consumers want, if they were truly committed, “they’d be backscaling and rethinking what luxury means in the climate crisis.” But it’s complicated: most of what the brands do isn’t enough, he said, but they have to start somewhere. You can’t change all of the practices of these hundred-year-old companies overnight.

To Kloves, the environmental problems that plague the fashion industry can’t be solved just by switching to new materials or using less water. Rather, some of them are built into the system’s scaffolding, and, as he sees it, the people currently running these multi-national fashion conglomerates aren’t going to be the ones to bring about the necessary changes.

Gucci’s spring-summer show in Milan, which the company promoted as carbon-neutral.

Kloves is currently doing an internship in New York at Bode, the 2019 CFDA/Vogue Fashion Fund award winner for emerging designer, which uses primarily antique textiles and other vintage materials to create unique men’s-wear pieces. He said everyone at the company is 30 or under, including Bode’s namesake and designer, Emily Bode.

According to Kloves, “It’s a really different environment” from other fashion companies where he’s had internships, which are often beset by hierarchical structures that get in the way of progress. He doesn’t foresee that his peers will be able to make the changes they want by working within the existing structure. “There needs to be an ushering out of a lot of people that are refusing to move on. Some people can probably bring new ideas to the table, but I think it’s going to become something where these brands will look to contemporaries having success.

“I think it will come from reacting to outside forces rather than from within the companies themselves,” he said.

“There needs to be an ushering out of a lot of people that are refusing to move on.”

Some in the industry are taking notice of what these young talents want. Gabriela Hearst, 43, a designer deeply committed to environmentalism—she staged the first carbon-neutral runway show, eliminated plastic from her company, and has a goal to stop using virgin materials by 2022—said, “For the majority of the new generation of fashion students, their No. 1 priority is the environment and how to start a business sustainably. From Parsons to the LVMH prize, this is the new normal for them—if you are going to start a business, it can’t be done in a system that evidently is not functional.”

Scout’s Honor, designed by Boy Kloves, is made entirely from upcycled Boy Scout patches and deadstock tie silks.

Still, there is an unavoidable dialectical contradiction: designing new clothes for sale requires the production of new clothes, and success spurs growth, which means more production of more things, which inevitably means more waste. If the materials are made in a closed-loop system or are biodegradable, the effect is somewhat mitigated, but resources are still used to make new things, even if they’re recycled materials. There might be enough existing clothing in the world that we could all wear secondhand forever, but given that only about 15 percent of clothing in the U.S. is donated or recycled, it seems unlikely.

Matthew Needham, who is committed to upcycling—elevating a given material above its original purpose, basically turning trash into treasure—has a different philosophy: “We’ll be using clothing as something more than a commodity in the future—it won’t be about making things to sell things; it’s about making things that have a purpose. I wouldn’t be making more stuff if I didn’t think I could say something better than someone else. No one would question an artist for making something because they had something to say.”

Others have turned to more commercial models. Sara Arnold, 33, another recent graduate of Central Saint Martins, founded Higher Studio, a clothing-rental company in which many of the brands retain ownership of the rented clothing, providing an incentive for them to create clothes that last as long as possible, and get the materials back at the end of life. Phoebe English, another designer, produces all of her clothing in London, with 100 percent of the materials coming from within a 15-mile or so radius of her studio, ensuring transparency and minimizing transportation emissions.

“We’ll be using clothing as something more than a commodity in the future—it won’t be about making things to sell things; it’s about making things that have a purpose.”

There are lots of wrong ways to do sustainability, or there are many ways to be unsustainable. True sustainability—products that have a minimal impact on the environment or human health—is much harder; every designer can prioritize different aspects but leave much of their process or supply chain unaddressed, since they operate within a profoundly flawed system to begin with.

A design from Gabriela Hearst’s spring-summer 2020 collection, billed as New York’s first carbon-neutral runway show.

It’s something that has been frustrating to Phoebe English as she tries to minimize the impacts of producing her line. “I realized very quickly it was a big subject and I wouldn’t be able to do it perfectly right away, which is a very difficult thing for a designer to accept,” she said. “I was worried I would feel like a hypocrite,” she added, articulating a perception that plagues many design companies when they start down the road to sustainability, which English says can be discouraging for those who are trying to change. “I realized that any start was something,” she said.

She went on to say that, because the means and processes of production are often at a remove from those making the clothes (it’s hard even for interested designers to get the information they need), collaboration is particularly important. “We can’t afford to be competitive or have ownership over this information.”

“Fundamentally, this is information that will help us survive, and that everyone should be able to have whether they can afford a sustainability consultant or not,” she said.

As designers, she added, “it’s our responsibility to play an active role in redesigning how clothes are made and sold. Problem solving is what we do. The environmental and ecological crisis stems from a design flaw, and if there’s something a designer knows how to deal with, it’s a design flaw.”

Tatiana Schlossberg is the author of Inconspicuous Consumption: The Environmental Impact You Don’t Know You Have