The biggest single move by Starbucks’s customers who want to go green might be to stick with black coffee.

Overall, dairy accounted for 21% of the company’s global carbon footprint in 2018, the latest year for which data is available. That’s a figure the company wants to reduce as part of a new, larger sustainability commitment released Tuesday. But even the dairy “fix” isn’t without a cost for Earth, a realization that may prompt greater support of sustainable farming all around (Starbucks is backing these efforts, as well) over substitutions at the counter.

With Tuesday’s pitch, “our aspiration is to become resource positive — storing more carbon than we emit, eliminating waste and providing more clean freshwater than we use,” CEO Kevin Johnson wrote on the Starbucks site.

Animal protein has been the highest contributor to carbon and water usage in the food category across the beverage and sandwich seller’s SBUX, -2.07% operations and supply chain, which has been mindful of responsible coffee bean-growing methods. As part of its stepped-up sustainability pledge, the company has recently included more almond, coconut and oat dairy-alternatives to cow and soy milk at its stores.

Now, Starbucks is considering adding plant-based meats to its menu as well, according to news issued Tuesday that sent shares of realistic meat-alternative Beyond Meat BYND, -5.20% already up nearly 45% over the past year, higher yet again. Starbucks shares, meanwhile, are up 43% over the past year.

Read:Beyond Meat’s stock is still rising, but the ride is getting a bit rough

And:People are willing to pay nearly twice as much for plant-based milk

Steamed milk and a light layer of foam

Starbucks already offers a 10-cent credit for customers who bring in their own cups and will test other incentives to encourage customers to waste less, but when it comes to behavior at the store, dairy and meat use remains a key area of exploration.

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CEO Johnson will encourage consumers to choose milk made from almonds, coconuts, soy or oats, whose production is environmentally friendlier than dairy, he said in a Bloomberg News interview. In North America, 15% to 20% of Starbucks customers already choose such options.

“Alternative milks will be a big part of the solution,” Johnson said in that interview. “The consumer-demand curve is already shifting.”

Starbucks, when asked by MarketWatch to expand on alternative-milk use, including these products’ own imperfect environmental record, said it had no further information to add at this time. Environmental activists, food and wildlife experts, as well as advocates for sustainable investors offered generally positive reactions to these moves by a retailer with as much global presence as Starbucks. Still, some were quick to point out that dairy and meat alternatives do carry their own climate-change risks.

“This is exactly the kind of leadership we need to see from businesses — an opportunity to invest in their own future while making their global customer base a partner in this sustainability journey,” Sheila Bonini, a senior vice president in private-sector engagement with World Wildlife Fund, said in a release.

WWF has previously issued research pointing to risks for deforestation from soybean growth. A request by MarketWatch for an expanded response from the WWF was not immediately answered.

Soy produces more protein per hectare than any other major crop but its rising popularity also poses a risk to deforestation in major producer Brazil and elsewhere. It it is one most profitable agricultural products, according to the WWF, in this report. Soybeans of a certain variety can be eaten directly by humans, including in soy milk, but most are crushed to produce protein-rich soy meal to feed livestock. Soy oil is used in food, cosmetics and soaps, and as a biofuel.

Almonds, meanwhile, have been the subject of a recent investigation by the Guardian, which sought to find the sources for the deadly destruction of the global bee population, itself a major environmental concern over lost pollination. Primarily, pesticides have been the major culprit in decimating bees, but almond farming techniques could share some blame.

A separate National Public Radio report claims that some almond farmers are using risky pollen and nectar substitutes to get bees to repopulate their hives in winter, when bees are supposed to be dormant; bee loss has been accelerated with the practice, both reports argued. Bee colony deaths surpassed all-time highs last year, with beekeepers reporting an average loss of 38% of honeybee colonies in the winter season, per a 2019 survey issued by the Bee Informed Partnership, a nonprofit established by the U.S. Department of Agriculture.

The Agricultural Marketing Resource Center says the American almond industry has been growing steadily. Each American, on average, consumes more than two pounds of almonds each year, including in almond milk. Since the demand has been so high, almond growers have started to farm their fields earlier in the year.

Related:Coffee drinkers have to stop double cupping their Dunkin’ — yes, even in New England

These findings will only heighten the battle with the dairy industry. The $35.5 billion U.S. cattle milk industry has long been challenging the $1.6 billion plant-based milk industry’s right to use the word “milk” with its offerings. Plant milk producers say the rules amount to protectionism, while the dairy industry has tapped health officials and a friendly regulatory climate under the Trump administration for help in clarifying the differences. For example, vitamin B12, which is required for brain function and is found in cow’s milk but not found in plants.

Dairy Management Inc., the dairy promotion trade group, said Tuesday that it, like Starbucks, wants a better lifecycle assessment of its environmental footprint and believes that public-private collaborations are essential.

“From an environmental and nutrition standpoint, it is not an either/or. Both plants and animals play a critical role in the health of the people and the planet,” said Krysta Harden, the group’s executive vice president in global environmental strategy, who said the dairy industry will soon share its plans for progress toward carbon neutrality and soil and water health.

The fast-growing plant-based meat alternatives market has its share of critics, including from the sustainable farming industry.

“We need to look closer at what goes into plant-based meat alternatives such as GMO corn and soy, which directly contribute to use of toxic herbicides,” said Blue Apron co-founder Matthew Wadiak, who now operates a direct-to-consumer chicken company called Cooks Venture. “These conventional crops are contributing to the problem, not solving the problem. Regenerative agriculture is proved to be much better from a climate standpoint than conventional crops.”

Emissions from livestock account for about 14.5% of total greenhouse gas emissions, globally, and roughly two-thirds of those emissions come from cattle, particularly the methane gas emitted by the animals, according to United Nations data.

Halve emissions in a decade

Starbucks said its preliminary targets for 2030 are to cut carbon emissions by half in both the company’s operations and supply chain, halve water usage for operations and coffee production and cut by 50% the amount of waste sent to landfills (it has already started to eliminate single-use plastic straws). The company will also shift to reusable packaging, invest in innovative agricultural practices and forest conservation efforts, better manage waste and create more eco-friendly stores, it said. Along with McDonald’s MCD, -1.03% , Nestle and other multinational companies, Starbucks is a partner in the NextGen Consortium to fund recyclable and compostable cup designs.

In 2018, Starbucks emitted 16 million tons of greenhouse gases, withdrew 1 billion cubic meters of water and created 868 kilotons of waste throughout its supply chain, including at its stores, according to an audit the company sought with sustainability consultant Quantis and the World Wildlife Fund.

Overall, Starbucks has had a mixed environmental report card when actual results are measured.

In 2008, Starbucks committed to serving 25% of its drinks in reusable cups by 2015, a goal it missed and revised. Starbucks is not included in the updated “A list” for 2019 which tracks the world’s pioneering companies leading on environmental transparency and performance issued by nonprofit climate disclosure group CDP.

Proxy action works

For consumers not ready to forgo a milky latte but still sensitive to preserving life on Earth as we know it, the coffee chain with 31,000 locations in 80 global markets is only the latest among multinationals with big announcements recently, including BlackRock BLK, +1.55% , the world’s largest fund firm, who said it will divest from some coal exposure and push sustainability goals as it pursues profits, and Microsoft MSFT, -1.24% , which wants to erase all of the carbon footprint created since its 1970s genesis.

As for investors, Starbucks’ action comes in part at the prompting of its shareholders. A green-minded proxy push, actions to get corporations to respond to social and other demands, has been on the rise. For Starbucks specifically, a resolution calling on the company to step up the use of sustainable packaging earned support from almost half of shareholders at its annual general meeting last year.

“While Starbucks has a long road ahead to achieve these goals, we’re encouraged that its priorities are rooted in transparent data and will be supplemented by first-of-its-kind market research,” said Allan Pearce, shareholder advocate for Trillium Asset Management, in a release. The money manager, along with sustainable-investing advocacy firm As You Sow, has withdrawn its shareholder proposal meant to push Starbucks to greater “green” actions now that Tuesday’s steps were announced.

MarketWatch retail reporter Tonya Garcia contributed to this story.