They are the Stanley Cup champions. And that's a lot of mugs.

The Stanley TumblerThis year's big hit is, at first glance, a victory for the planet.

It is sustainable. It is reusable. Unlike the single-use plastic bottles it has to replace, it does not generate mountains of plastic waste.

But the craze has led to less sustainable behavior. People bragging about owning dozens of them. When Target released special editions, including a coveted Starbucks version, it caused a… mini stampede.

Some trend forecasters say the craze is already over. “Some millennials or Gen-Z are already embarrassed to wear a Stanley,” says Casey Lewis, writing the trendspotting newsletter After School. “And we know what's going to happen,” she said. They sit unused, collect dust on a shelf or in a basement, or “in the worst case, they end up in landfills.”

Stanley Mania is a story about how marketing, influencers and the power of social media came together to produce a cultural phenomenon. Stanley sold an estimated 10 million Quencher water tumblers in 2023, and the company's total sales for the year are expected to reach $750 million, up from less than $100 million in 2020. The #StanleyCup hashtag has been viewed billions of times on TikTok .

But the trend is also an example of how a growing universe of environmentally conscious products — things originally marketed to be sustainable — can turn into a catalyst for simply buying more, potentially negating the environmental benefits . Access roads have become crammed with bins meant to save us from the scourge of single-use plastic bags. Cupboards pile up odd gadgets, like collapsible steel straws or reusable food containers, meant to reduce the number of disposable items.

“The thing about a reusable mug is that in theory you only need one. And you replace dozens or even hundreds of disposable cups with that one reusable mug,” says Sandra Goldmark of the Climate School at Columbia University. But if someone buys a lot of those mugs, “you have to drink a lot of water,” she said, to make up for the environmental impact of producing them.

There are indications that sustainability sells. a study last year from McKinsey, which examined five years of sales data from 44,000 brands, found a clear link between consumer spending and sustainability-related marketing.

That study did not specifically include Stanley bottlenose dolphins. And for most products, switching to a more sustainable alternative does not necessarily mean more consumption. You may no longer eat vegetables because, for example, they are sustainably grown.

And most Stanley mug owners probably don't have museum-scale collections, or even more than just one or two. Even if they do, the toll on the climate would be much lower than, say, driving a gas-thirsty SUV or flying around in jet planes.

Researchers have coined a term to measure the amount of time someone must reuse an alternative before it fully offsets the single-use product it replaces: the environmental payback period. a 2020 paper found that for straws, coffee cups and forks, metal alternatives needed to be used the longest – anywhere from a few months to a few years – to break even.

Several things play a role in that long playback period. For starters, making stainless steel is a polluting and energy-intensive process that relies mostly on coal, a dirty fossil fuel.

Stanley advertises that its products will last a lifetime. (That they are built to last was spectacularly proven when a popular social media post showed a bottlenose dolphin that had survived a car firethe ice cream inside still hasn't melted.) But more recent marketing has emphasized limited edition items and a dazzling array of colors.

Stanley said it is committed to making its products from more sustainable materials. The mug's manufacturer, PMI, which also owns the Aladdin brand, says Quencher cups are made from 90 percent recycled steel.

But of all Stanley products, only 23 percent are made from recycled steel. according to the company. The intention is to increase that at least 50 percent by 2025.

Philippe Pernstich of Minimum, a carbon accounting software platform, said this would be difficult. First, there is a shortage of recycled steel because it is in such high demand. Making steel from raw materials is much more expensive and energy intensive, and emits pollutants that warm the planet.

Some cup brands offer trade-in or recycling programs. Companies could respond to that, said Columbia's Prof. Goldmark. “What if they offered a repair or refurbishment service? What if you could make your existing cup dazzle?” she said. 'There are all kinds of fun ways to let people have fun with your product' instead of 'making more and more'.

All things considered, there's no doubt that a culture shift to reusable bottles is good for the planet. Single-use plastic water bottles have their own carbon footprint and release microplastics are rarely recycled: the recycling rate for plastics in the United States has been remained below 10 percent for decades.

“I think the cool thing about this 'it' water bottle trend, as silly as it may be, is that reusable bottles are becoming cool,” says Ms. Lewis, the trends expert. “It ensures that people never want to leave home without it.”

There's already a new 'it' bottle on the horizon: the Owala. Owala bottles are already everywhere on college campuses, Ms. Lewis said. Their appeal: “When you drink it, when you tip it back, you look like a cute little panda bear.”