Fighting climate change is a growing priority for fashion companies, with British luxury house Burberry the latest to announce a strategy to slash  emissions across its supply chain.

But while the fashion industry wants to help the planet—the apparel business creates around 10% of global greenhouse gas emissions—companies are also responding to consumer demand for products with more sustainable origins.

According to the Sustainable Apparel Coalition's 2019 Pulse of the Fashion Industry Report, 75% of consumers view sustainability as very or extremely important. Half of shoppers said they would switch brands if a competitor is more environmentally and socially directed. Yet, "companies are not implementing sustainable solutions fast enough to counterbalance the negative environmental and social impacts," the report said.

Establishing its sustainable bona fides, Burberry is aiming to reduce climate-changing greenhouse gas emissions at its stores, offices, internal manufacturing, and distribution sites 95% by 2022, and by 2030 cut these pollutants 30% throughout its extended supply chain.

The latter goal is especially significant, taking into account the global reach of an apparel, accessory, and footwear label's supply chain, and how difficult it can be to regulate carbon emissions of every manufacturer, as well as throughout transportation, distribution, and retail channels.

Equally noteworthy is how Burberry has joined a broader effort among businesses, and a growing cadre of fashion names across the industry,  as members of the Science-Based Targets initiative, started in 2015.

Science-based targets

The initiative is a collaboration among the CDP (formerly the Carbon Disclosure Project), United Nations Global Compact, World Resources Institute, and World Wide Fund for Nature. The coalition has 575 companies who've committed to create climate-change-reduction programs, of which 231 have reached the point where they can set measurable targets based on scientific principles.

Other fashion companies who have either committed to create or have already set goals under the initiative include: Chanel, Gucci-parent Kering S.A., PVH Corp., Nike Inc., Puma SE, VF Corp., Hennes & Mauritz, Eileen Fisher Inc., Guess? Inc., Levi Strauss & Co., Gap Inc.,  Zara's parent company Inditex S.A., Uniqlo's parent Fast Retailing Co., and One Jeanswear Group, makers of denim brands such as Nine West, Gloria Vanderbilt, and Bandolino. Among retailers, whose sales include fashion, and are part of the initiative, are Walmart Inc., Target Corp., Tesco PLC, Marks & Spencer Group, and Carrefour S.A.

For these companies, emission reductions are planned "across all their products, their whole value chain," said Cynthia Cummis, director of Private Sector Climate Mitigation at the WRI, a global environmental research organization. As a result, participants are "aggressively addressing climate change in line with the ambition of the Paris Agreement" setting global goals to reduce greenhouse gas emissions.

The Science Based Target initiative defines a “science-based target” as a goal adopted by a company to reduce greenhouse gas emissions. These goals are set to meet broader objectives to keep global warming well below a level of 2°C (35.6°F) above pre-industrial temperatures, and not to exceed 1.5°C (34.7°F), according to benchmarks reported in the 2018 Intergovernmental Panel on Climate Change’s Special Report on Global Warming of 1.5°C.

Going forward, Cummis said the initiative wants to gain broader knowledge of the fashion industry, "to understand where the most emissions are along the value chain, where the biggest reduction opportunities are, and map out for apparel companies how those activities can add up to meet a science-based target," Cummis explained.

Small and big steps for the planet

Participating companies in the initiative also pledge to be transparent about their nitty-gritty goals by keeping the public apprised about progress.

Measures to reduce emissions can include using recyclable materials, but also something as basic as reusing cardboard boxes or creating operating efficiencies. Reducing or replacing petroleum-based materials is another step. For example, citrus-based textiles are made by Italian fiber company Orange Group, whose customers include fashion house Salvatore Ferragamo.

Burberry's sustainability efforts, large and small, in total go well beyond its decision last year to stop the practice of burning unused stock, seen as polluting and wasteful.

Since the fashion house estimates 76% of its direct carbon emissions come from its retail operations, the company has appointed Responsibility Leaders in several stores to get staff to increase energy efficiency.

The brand's stores also have switched to LED lighting. "We then used the cost savings from energy reductions to finance additional renewable energy procurement," the company said in a statement. "We are on track to achieve our RE100 commitments as we now obtain 58% of our total energy (including 68% of our electricity) from renewable sources, an increase of 13% from last year." Throughout its supply chain, the brand is also moving toward renewable energy sources, such as wind and solar power.

What is sustainability?

As consumers focus on pursuing eco-friendlier lives, more fashion and other consumer products are being sold as"sustainable," although there isn't a standard definition for what that means in terms of the environment.

Projects like the Science-Based Targets initiative help brands back their sustainable claims with a set of standards to which they can point to as proof of their commitment. Meanwhile, French President Emmanuel Macron recently tapped Kering SA Chief Executive Officer Francois-Henri Pinault to lead a global fashion industry sustainability effort, but there's been no discussion yet about marketing guideposts.

"Since no one so far can really define sustainability exactly, it is hard to imagine how it can be policed” to prevent false claims in marketing, said Jeffrey Silberman, professor and chairperson of the Textile Development and Marketing department at the Fashion Institute of Technology, New York. (When reached by Fortune, he was in North Carolina visiting a cotton farm.)

Some countries do have agencies in place to hold companies accountable for their marketing language. Norway, for example, is currently investigating H&M's fashion marketing around its summer "Conscious" collection.

In the U.S., the Federal Trade Commission provides guidance on marketing language, compliance with which is voluntary but is nonetheless weighed as regulatory authority. But the FTC so far hasn't passed judgment on what constitutes "sustainable" in product advertising.

With the 2012 release of revised "Green Guides" for environmental marketing language, the FTC said it "lacks a sufficient basis to provide meaningful guidance" on defining sustainable, as well as natural and organic, since each has various meanings.

Regardless, being able to credibly say a company is sustainable requires a lot of work and longterm commitment. "I think it's going to be a combination of lots of activities that companies are going to need to put in place to claim that they're sustainable," Cummis said.

"But I assume it will be a collection of investing in energy efficiency in their supply chain," Cummis said. "For apparel companies, the majority of emissions are primarily upstream in their supply chain, with the extraction of raw materials or the [manufacture of] fabric at the textile mills."

To cut down on emissions, a company could switch to textile mills using renewable energy, or have circular-business models that reduce waste, she said.

There are also independent organizations doing sustainability oversight, according to Katrin Ley, managing director of Fashion for Good, a global sustainability initiative supported by companies like Adidas, Galeries Lafayette Group, Kering, PVH Corp., Stella McCartney, and Target.

"Working with these organizations or using materials that meet particular standards all help the wider industry and consumers understand where a brand is on the spectrum," she said. These organizations include the Road Map to Zero Programme, Sustainable Apparel Coalition, Better Cotton Initiative, Fair Wear Foundation, Cradle to Cradle Institute, and the Ellen MacArthur Foundation.

Brands at the Forefront

Some brands have been transparent about their sustainability initiatives since the beginning. One company doing this effectively is Reformation, a celebrity-favorite line known for blousy dresses and tops with low necklines. (Its website reads: "Being naked is the #1 most sustainable option. We're #2.)

Because there is no standardized framework for evaluating the sustainability of fibers, the company has released its own set of fiber standards. Grade A fibers are "Natural fibers that are rapidly renewable, plant-based and have a potential for circularity," such as recycled cotton, Tencel Lyocell, and organic linen; grade B fibers are "almost all natural or recycled fibers" like organic cotton, ENKA Viscose, and Tencel Modal.

"We tried to make these standards as holistic as possible, taking into consideration water input, energy input, land use, eco-toxicity, greenhouse gas emissions, human toxicity, availability, and price," said Kathleen Talbot, Reformation's VP of Operations and Sustainability, in a statement to Fortune. "At the end of 2018, about 67% of our fabric purchases were our A & B rated fibers, and we are continuing to develop new fabrications and design into these highest impact fibers like Tencel, linen, and recycled cotton or wool."

A New Generation of Shoppers

Reflecting this interest, a 2015 Nielsen report found 73% of millennials are willing to pay more for a product if it is marketed as sustainable.

"Despite the fact that millennials are coming of age in one of the most difficult economic climates in the past 100 years, they continue to be most willing to pay extra for sustainable offerings--almost three-out-of-four respondents," the Nielsen report says.