“Overwhelmingly, these campaigns do reach new audiences for us,” she said, but wouldn’t share specific figures. “Our focus is really on bringing new people into the thredUP world who either have never shopped on thredUP or even never shopped secondhand.”

Fashion’s climate mess

But while the spirit of the campaign is a positive one, experts warned that secondhand shopping alone can’t address the harms generated by the culture and industry of fast fashion.

“Promoting resale and reuse is a good thing overall, the goal being to keep already extracted materials in use for longer,” Lynda Grose, professor of fashion design and critical studies at California College of the Arts, told Adweek. Theoretically, she explained, resale could reduce the need to extract new materials.

But despite the rise of resale-as-a-service platforms like thredUP, “no one’s resale business—including Patagonia’s—is displacing their new product production,” Grose said. “And unless that displacement happens, ecological impacts and carbon emissions will continue to increase.”

Carbon emissions generated by the apparel industry are estimated to make up somewhere between 1.8 and 10% of global emissions. Despite wider adoption of sustainable practices and programs, the industry’s footprint continues to grow year over year. At the same time, the portion of new garments made of petrochemical-based synthetic materials has skyrocketed to over 60%.

“We should be teaching children that one-off outfits are unsustainable and simultaneously name and shame those providers who are creating all this merchandise for which we have no place in the landfills,” said CB Bhattacharya, Zoffer chair of sustainability and ethics at the University of Pittsburgh.

Still, amid the sea of bright pink, petrochemical-based merchandise accompanying the new Greta Gerwig film, thredUP’s sustainability-focused campaign is a rarity.

“As a former vintage seller and designer known for period pieces, I’m passionate about reimagining the old and turning it into something entirely new,” Durran said in a statement.