From cowboys to presidents, supermodels to gardeners, you would be hard-pressed to find someone who doesn’t own a pair of blue jeans. Denim, a heavy-duty cotton twill, is one of our most enduring and versatile wardrobe staples. It can be deep indigo or faded blue; high-rise or low-rise; made into dresses, shirts, skirts and even tuxedos (although I’d add that just because it can, that doesn’t mean it should.) But with more than 1 billion pairs sold every year, the fabric also comes with a heavy environmental cost.

Let’s imagine your favourite jeans. They started off in a field of cotton—or more likely hundreds of different fields—probably in India, China, the US, Brazil or Pakistan, the five countries that make up 75% of global cotton production. Once the fibres have been separated from the seeds, in a process known as ginning, they’ll be spun into yarn and subsequently dyed. For denim, that usually means an indigo dye. Once woven and sewn into garments, fashionable faded looks are created through finishing processes such sandblasting, stonewashing and acid-washing. It’s a long and complicated supply chain spanning multiple countries and businesses.

Every step comes with a significant environmental effect. According to Levi Strauss & Co., a pair of 501 jeans, the company’s signature cut, used nearly 3,000 litres of water by the time it hit the shop floor and emitted 20kg of CO2e (a measure that encompasses all greenhouse gases) in 2015. Prolific use of pesticides and fertilizers are bad for both nature and human workers. Indigo dye used to be natural, made from the leaves of the indigofera tinctoria plant, or true indigo. Now, however, the vast majority of dye is synthetic and contains toxic pollutants, including formaldehyde and cyanide. In some parts of the world, waste from the dye process is dumped straight into waterways, tinting rivers the colours of the forthcoming fashion season. Finishing processes can be equally polluting, resource-intensive and dangerous for workers who, too often, aren’t given the right protective equipment.

Of course, many of these problems aren’t restricted to denim production. Cotton is used in about half of all textiles. But the ubiquity of blue jeans makes them a powerful symbol. What will it take to turn them green?

The first step is making denim’s origins completely traceable. If a brand doesn’t know what’s happening in its supply chain, then it can’t ensure that it’s making a positive impact—or not having a negative one.

That’s more complicated than it sounds. A yarn could contain cotton from hundreds of small farms, as bales of ginned cotton will be blended to achieve the desired quality and specifications. Large clothing companies are also extremely fragmented, with everyone working in their own silos, as designer Anne Oudard and sustainable denim consultant Ani Wells explained to me. Recounting one honest answer they got from someone in the industry, Wells said: “They’re like: ‘I’m too stressed already. That’s the other person’s job, why do I have to think about that, too?’” The first in a series of denim research studies by Oudard and Wells used the example of a designer sampling a garment in a traceable organic denim. But there are conflicting responsibilities: By the time the style is produced, buying teams might have chosen a cheaper fabric to reduce costs. Equally, no one person at these companies knows everything about a pair of jeans, so information—such as whether certain suppliers have been audited or not—can slip through the cracks.

It ought to be possible—cotton isn’t a gas; it’s a valuable, physical commodity. Coffee and cocoa have lessons to offer after big pushes to increase the traceability of those goods. Oudard and Wells both agree that cotton traders—typically the middlemen between farmers and spinners—have a big role to play in helping improve their commodities’ traceability and sustainability. There’s a trend now to cut them out and go straight to the farm, but their knowledge will be integral.

There’s also plenty of innovation in the sector aimed at cleaning up denim’s life cycle. Good Earth Cotton is a regenerative producer that aims to enhance soil carbon uptake and improve biodiversity with its growing methods. FibreTrace incorporates luminous fibers into textiles to create a supply chain that’s fully traceable from field to shelf. Huue is creating nontoxic biosynthetic indigo out of sugar. Xeros Technology has developed reusable polymer spheres to replace pumice stones in denim finishing and halve the amount of water needed for the process.

But there’s one drawback: expense. Though there are some innovative brands willing to invest, Wells said that brands typically want to keep things cost-neutral, making it much harder for sustainable startups to scale and subsequently lower prices. The current economic environment is no help. Levi Strauss, for example, just cut its full-year sales outlook as inflation squeezes customers’ purchasing power. Brands may be wary of raising prices more than they need to.

Cost-neutrality is perhaps one of the reasons the Better Cotton Initiative has been so successful, counting many big fashion retailers including Marks & Spencer Group Plc and Hennes & Mauritz AB as members. The sustainability program doesn’t place a price premium on its cotton, unlike organic or regenerative fibres, which can cost as much as 20% more, and doesn’t have the same stringent certification requirements as organic standards do—pesticides are allowed, for example—but it does work with farmers to help them reduce water and chemical use and respect workers’ rights. It’s been effective at making inroads into the industry—about 22% of global cotton production is Better Cotton, compared with organic cotton, which accounts for just 1% of global production.  

It’s a good start, but it’s important to remember that growing is only one part of denim’s environmental impact. Which brings me to the final challenge to overcome. Because there’s no definition of what a sustainable pair of jeans looks like, brands are free to dictate their own standards. “The problem that we have at the moment is that brands are asking for things from their own perspective, usually with marketing and communication targets and mindsets,” explains Oudard. “They want things they can talk about, and some topics in sustainability aren’t sexy, but they might have a higher impact.”

That might be hard in an industry based on appearances but, if we’re going to make truly planet-friendly jeans, companies will have to immerse themselves in every part of their products’ life cycles, break down those silos and swallow some higher costs.

Lara Williams is a Bloomberg Opinion columnist covering climate change.