Companies are staring to do more to measure their impact on the environment.

Fashion is in a bind.

The mission? The industry has to save its part of the planet.

But where to start: The oceans? The air? The flora? The fauna?

And what is actually in need of saving and what needs saving first — and how does one go about it and what steps toward sustainability actually help? And how does one make a buck while they do it?

Sustainability as a term speaks both to business that operates in a way the doesn’t destroy natural resources and to one gigantic measurement problem.

In finance, companies operate under generally accepted accounting principles and although publicly held companies do their best to point to other measures of profitability and growth, the rigid GAAP framework at least lets everyone talk about money matters with the same vocabulary.

The same is not true in sustainability.

That’s starting to change with green bean counters starting to build a new field: Natural capital accounting.

Eco-consultant Pei Yun Teng, A.T. Kearney’s global director of social impact, said it is still a very new area, but one that’s important for the sustainability movement and companies looking to lessen their eco footprints.

But things get complex — and fast.

“How do we even value hidden social [and] environmental costs?” Teng said. “How do you value biodiversity when we don’t even know…the price of lost biodiversity? How do you value an extra year of clean air and what’s the impact on humans and animals? What can you even value and what does valuing it imply for the way we think about it? What is the scope? We have to draw that scope.”

Luckily, industry has some experience in the area.

Greenhouse gas accounting is fairly mainstream now, said Teng, noting that most big companies have published their greenhouse usage for years and break down the numbers.

“That’s fairly well documented by now, but it took a couple decades to get there,” she said. “Natural capital accounting, that journey is probably much younger.”

Fashion helped take some of the first steps.

Puma published an environmental profit and loss statement in 2011, valuing its impact in the areas of greenhouse gas emissions, water use, land use, air pollution and waste at 145 million euros.

As more companies make accountings of their environmental impact, the industry can start to establish benchmarks and measure progress.

“The assumptions are extremely sensitive and we don’t have at the moment a widely accepted international methodology,” Teng said. “As more companies come on board, we’re going to learn from each other. This is a great opportunity for the fashion industry to really understand how they can build a more sustainable business model.”

New business models are important as Teng said companies that used to find themselves accountable for just their own direct actions, or their supply chains, now face broader responsibilities. Brands are now becoming more accountable for the natural resources used to make goods and also for what happens to their products after the consumer is done with them.

This has led to the advent of circular companies such as For Days, which was founded by Maiyet cofounder Kristy Caylor. The service sends users T-shirts to wear and then takes them back for recycling when they’re done.

This type of thinking could become much more important if brands are held accountable for the broader impact of their goods.

Teng pointed to fast fashion, which might make a T-shirt for $5 and sell it for $10.

“There may come a day when regulators step in and say, ‘Hey businesses, you’re going to have to pay the full price of all the resources you’re using,’” she said, suggesting that $5 cost could skyrocket.

As a management team, she said, “You want to allocate your attention and resources accordingly.”

Saving the planet might be a big task, but it’s better to dive in and start somewhere and build expertise and experience.

“Businesses are recognizing that this is where we want to be headed,” Teng said.