Today, Stonyfield Farm, the organic yogurt company, is unveiling a new packaging solution: A yogurt cup made from corn.

It's not the first revolution in yogurt cups, or the first packaging innovation made from corn. But Stonyfield's journey to today is a case study in sustainability, innovation, persistence, and systems thinking that I think is worth sharing.

First, the basics. Stonyfield's new cup -- now being used in its multipack Yo-Baby products and a few others -- replaces polystyrene with a plant-based plastic called polylactic acid, or PLA. Essentially, it's a plastic made from corn.

The PLA is made by NatureWorks in Nebraska, which is owned by Cargill, then sent to Clear Lam Packaging in Illinois, where it is mixed with colorings and other additives and turned into rolls of plastic that are formed into cups at the Stonyfield Yogurt Works. The new package is 93 percent plant-based, with the balance being nontoxic colorings and additives.

The cups offer a number of advantages. Aside from the obvious -- substituting plants for petroleum -- PLA uses less energy and releases fewer greenhouse gas emissions than polystyrene over its lifecycle.

PLA is made from corn, which captures carbon as it grows, so PLA releases 48 percent less carbon into the atmosphere than polystyrene does from cradle to grave. For Stonyfield's 200 million-odd cups that translates to reducing its carbon footprint by 1,875 metric tons a year. That's no small number, since packaging represents Stonyfield's second-largest carbon footprint, after cows.

Moreover, the new packaging is stronger than the oil-based plastic it replaces, and offers some other performance characteristics. For example, it reduces breakage during shipping and forms a tighter seal with the lid. The plastic is stronger than polystyrene, so less is needed, making packages lighter. (One downside: PLA's strength dulls industrial cutting blades on packaging machines more quickly.) Because of PLA's higher efficiencies and lower losses, the shift to plant-based plastics can be done at no net cost increase to Stonyfield.

So far, so good.

But it's never that simple.

While PLA can be made from a range of materials, in the U.S. it is made from corn. And 70 percent of U.S.-grown corn contains genetically modified organisms, or GMOs, according to the U.S. Department of Agriculture's Economic Research Service. That means that in using PLA, Stonyfield, a company maniacally committed to organic farming, is supporting GMOs. And therein was a dilemma.

Stonyfield is not the first company to grapple with such issues. Sustainably minded apparel and footwear companies, for example, have looked at using PLA in their products and have become stymied, fearing backlash from consumers and activists for supporting GMO crops.

Many of the objections to GM technology stem from its potential use to create unnatural organisms -- for example, a plant modified with genes from another species of plant, or even an animal.

Another concern is that genes used to modify crops could escape into wild plants, creating "superweeds" highly resistant to pests, or alter plants in other ways that might cause damage to the environment. It is possible, this argument goes, that plants emitting their own toxins could lead to insects and other pests mutating into bigger, stronger, more resistant beasts.

A further concern is that GM crops themselves might prove to be harmful to either wildlife or the people who eat food harvested from the crops. Still another key concern is that genes escaping from the crops could pollinate non-GM crops that are being grown organically.

Stonyfield found what it determined to be an acceptable workaround: GMO offsets.

The company worked with the Institute for Agriculture and Trade Policy and its Working Landscapes Certificate program. The goal of Working Landscapes is to reduce the environmental impact of corn and other crops grown for industrial purposes, such as plastic and ethanol production.

Working Landscapes pays farmers who agree to grow the corn we need according to very strict sustainable production standards -- things like strengthening soil, protection air and water, and promoting biological diversity. Working Landscapes also ensures that non-GMO corn is used. It's seen as a win-win situation for farmers and the environment, and we hope other companies follow their lead.

This "offset" program means that the amount of corn produced using sustainable corn production practices through Working Landscapes will be equivalent to the amount used for Stonyfield's packaging needs — about 500 acres' worth in 2010 — although the sustainable corn itself may or may not actually show up in the final Stonyfield packaging.

Working Landscape meshed well with Stonyfield's longtime support for family farming.

"It's critical to us that the farmers get most of the money," Nancy Hirshberg, vice president for Natural Resources at Stonyfield, told me recently. "This is using the market to transform farming to what we believe are more sustainable practices."

She added: "We could bring over lactic acid made from non-GMO beets in Europe, or tapioca in Asia, or sugar cane in South America. But we really felt that moving American farmers to more sustainable practices was a better route to go."

Offsets are a decidedly imperfect solution, one not embraced by all environmental advocates, but Gary Hirshberg, Stonyfield's "CE-Yo" (and Nancy's brother), a longtime environmental advocate himself, saw no other viable option. "Obviously, we wish it were not corn," he told me. But, he added, "We can't afford to hang out in the black or white space — we've got to lunge into the gray here."

But there's an even greater good here that Stonyfield is pursuing: growing the market for PLA to reach a volume that makes eliminates the need for corn to make PLA. That's long been the ultimate dream of companies like Stonyfield: sourcing plastics from agricultural waste or high-yield perennial crops grown on marginal land unsuitable for food crops. According to the U.S. Department of Energy, the market for these so-called cellulosic feedstocks will be commercially viable within five years. But Stonyfield thinks it -- and its competitors -- can accelerate this.

Toward that goal, the company has decided to make this technology, on which it's been working for years -- open-source, available to its competitors.

"We had the opportunity for exclusivity on this, and it was not an option that we thought was ethical," said Nancy Hirshberg. "So, we're putting all of our studies on the Internet. We're welcoming other companies to come in to see how it runs. We'll be out speaking to others. We're really encouraging others to do this."

Said Gary: "The big win, as I've come to understand this, is that the only thing that the only impediment to getting to agricultural waste or algal waste PLA is volume. Every chemist I know on both sides of the Atlantic says it's only one thing that makes it five years instead of one year, that's volume. It's simple."

"That's why we're being really open-sourced about this," he added. "If Yoplait wants to do this, we're going to be thoroughly open-book."

It's a book whose final chapters have yet to be written, but the story line is promising: a forward-thinking company combining technical expertise, market savvy, and sustainability commitment to transform an industry, and maybe other industries, by breaking through barriers and taking a risk.

We need many more such stories.

Joel Makower is the executive editor of GreenBiz.com.

The photo illustration above shows the bottom of Stonyfield Farm's new yogurt cup with a superimposed company logo. In the inset photo, Stonyfield VP Nancy Hirshberg talks with corn farmer Robert Hawthorn. All images courtesy of Stonyfield Farm.