“Your outfit is killing the planet.” That’s the message footwear and clothing company Allbirds is using to raise consumer awareness about the fashion industry’s link to the climate crisis. Figures are debated, but an estimated 10% of annual global carbon emissions originate from the fashion industry.

Since its 2016 launch, Allbirds has been vocal about its aim to produce fashion with a smaller carbon footprint. Each item of clothing displays a carbon emissions score to let customers know the climate impact of their purchase. The company has pledged to halve its products’ carbon footprints by 2025, and cut them to virtually zero by 2030.

Founded by Tim Brown, a former New Zealand footballer, and Joey Zwillinger, a biotech engineer and expert on renewable fabrics, Allbirds’ first shoe was made from biodegradable merino wool. The company went on to make shoes out of tree fibers such as eucalyptus and uses recycled bottles for shoe laces and castor beans for insoles.

As the startup grows – it has an estimated $1.7bn valuation – it says it will continue to focus on environmental impact. Last year, Allbirds started its first apparel line, debuting a fiber it calls “XO”, which is made from discarded snow crab shells. In May, it announced a sneaker made in collaboration with Adidas that the companies say has been created with 63% fewer emissions than a comparable running shoe.

The Guardian spoke with Allbirds’ sustainability lead Hana Kajimura about the company’s efforts to talk to consumers about the climate crisis, whether the public is able to understand its carbon emissions labeling, and if it’s possible for the fashion industry to ever truly be sustainable.

How does Allbirds explain carbon emissions to customers?

As a company, we’ve identified that climate change is the biggest problem facing humanity. We have a responsibility to try to bring our customer along with that idea and help them understand the magnitude of the problem we’re facing. But it’s a really hard one to explain.

If we think about the world of sustainability, something like plastics pollution is much more tangible, much easier to communicate to your average consumer than something like carbon emissions that you can’t see or feel. It’s very scientific; it’s a lot harder to explain.

But I think the heart of it – and why we started labeling all of our products with their carbon footprints in 2020 – is that the best way to bring this idea into the broader consciousness and help people understand it is the prevalence and availability of information.

An average person can’t explain exactly what a calorie is and how it’s measured, but that doesn’t matter. What matters is that they can contextualize a calorie. It’s that context that needs to be created around carbon footprints as much or even more so than the science behind how it’s calculated. That will only happen if many other companies, not just in our industry but beyond, label products with this data.

What exactly do your carbon labels measure?

Inside each shoe or on the tag of each T-shirt there is a number representing the kilograms of CO₂ that were created in making that product. The number measures five things: raw materials, transportation, manufacturing, product use (washing and drying) and end of life.

We’re measuring the emissions created across the entire life cycle of that product, even after it leaves Allbirds. The customer sees the sum of that number but can also access the breakdown of it.

Do you think it’s possible for fashion companies to ever truly be sustainable or have a negligible carbon footprint?

What we’re seeing is a pretty incremental approach to sustainability. It’s: “How can we use recycled materials here and there, reduce our impact by a little bit?”

What we need is much more transformational change. If every pair of shoes were made with a carbon footprint that is a quarter of the industry standard, imagine how big the impact of that could be. But it takes discipline, it takes thought, and I think ultimately it will take some regulation to pull the whole industry along.

One area of work that Allbirds is really excited about is regenerative agriculture. We make wool sweaters. Imagine we make a wool sweater with wool that’s exclusively grown on regenerative properties, where those farms are actually being used to sequester carbon in vegetation and soil. You could imagine having a sweater that’s effectively a carbon sink.

What keeps you up at night?

Reports are coming now about how we are nearing or have even already reached some tipping points when it comes to climate change, and we only have a matter of years to really try to turn things around. I worry that conventional business wisdom just gets in our way and slows us down. I’m so grateful that I work at a company that actively wants to challenge those ideas, but that’s what keeps me up at night for the rest of the industry: will we be able to move fast enough to achieve what we need to?

What more can companies do to tackle climate change?

My call to action would be around labeling products, which requires measuring your carbon footprint. You can’t possibly reduce what you don’t have good measurement for and it also creates additional accountability for the industry to keep driving footprints down.

What is your hope for the future?

That one day the fashion industry can move away from just doing less bad and work towards doing more good. I hope there’s a future where the clothes that we wear are made from natural materials rather than plastics that are tied to the petroleum industry. I hope our clothes are made from natural materials that are actually sequestering carbon in their production, so that our industry can be a carbon negative one.