There are 350 million people—more than the population of the US—currently taking a stand against climate change in China. But these activists are not actually taking to the streets, nor even physically planting trees. Instead, their newfound social empowerment is contained to a glowing screen open to the Alipay app, one of China’s two most popular forms of electronic payment.

Alipay’s foray into social engagement began with the release of the Ant Forest mobile game last year. Players are awarded green energy bubbles based on their real-life actions to reduce their carbon footprints, as determined by the China Beijing Environmental Exchange. These bubbles can be shared or stolen from other users and used to water a virtual tree; once a tree matures, the points accumulated can be redeemed to plant an actual tree in a real deforested area.

Alipay’s goals fit with the government’s own plans to defeat deforestation, which included a “total ban” on the domestic logging industry in 2017. The “Great Green Wall” of China, a 30-year mission to plant 66 billion trees to combat the encroaching desert that already covers a quarter of China’s landmass, has already seen some success: Hebei province’s Saihanba Plateau, once a dusty wasteland, is now the world’s largest manmade forest.

So far, over 56 million “Ant trees” have been planted by players across the country, prompting Fortune magazine to list Alipay’s parent company, Ant Financial, sixth in its 2017 “Change the World” list. The game’s image and popularity have been bolstered by innovative features: When some skeptics questioned whether Alipay was actually planting trees, the company provided access to satellite technology to monitor the growth the forests.

In a stroke of marketing savvy, the game recently allowed groups to pool their bubbles and dedicate an “Ant tree” in honor of an ancestor, family, partner, company, or even graduating class. This is how Ms. Xiong, a 24-year-old insurance broker in Chengdu, began using the game as a part of her daily routine.

“My mother wants to plant a tree in the Ant Forest and name it after my grandfather,” Xiong told TWOC. “She got me, as well as all of my aunts and cousins, using the app every day.” Xiong enjoyed stealing bubbles from her aunts, which often prompted them to call her up and scold her. But she particularly liked that the frivolous fun was able to translate into something meaningful—making a difference in China’s environmental problems, as well as honoring her grandfather’s legacy.

Le Shen, senior public relations adviser for Ant Financial, is proud that he has already planted two trees, one for each year he has played the game. “In 2015, the smog in Beijing was terrible and people were feeling the pinch of a degraded environment,” Le, one of the very first users of Ant Forest, told TWOC. This prompted three Ant employees to start brainstorming solutions outside normal working hours.

No one anticipated the success of the project when it first started, Le laughed, remembering that there weren’t even designated servers or bandwidth for the initial Ant Forest, leading to several mishaps early on.

The early success of Ant Forest can be attributed to widespread anxieties over pollution, as well as the rapid ubiquity of smart phones, broadband, and electronic payment schemes that allow Alipay to easily keep track of carbon-offsetting activities: Users can boost up on green energy bubbles by walking or using dockless bikes, such as the Alipay-invested Ofo. Additionally, shoppers can reduce carbon emissions by making daily transactions (household utilities, subway tickets, or groceries) with their bank-account linked app.

While reducing the number of four-inch receipts and ticket stubs might not seem world-changing behavior, Le believes that, through economies of scale, “just the smallest change of behavior can have a huge impact.”

It should come as no surprise that almost all these green energy activities incentivize the use of Alipay’s payment platform. Indeed, since the introduction of Ant Forest, users are spending substantially more time on the app—giving Alipay an edge over its social media-driven rival, WeChat Wallet. However, Ant Financial’s commercial interests are exactly what make the project both sustainable and relevant to the future of humankind, says Simon Zadek, co-director of the United Nations Environment Program’s (UNEP) Inquiry into the Design of a Sustainable Financial System.

Under Zadek’s leadership, the UNEP partnered with Ant Forest just a month after its release, noting that, “Historically, the United Nations’ engagement has been with governments…In the 21st century, we have realized that this government focus has its limits and to bring about change, we must harvest other mechanisms of engagement, especially inside the market with the digital world.”

Alipay’s 520 million users illustrate the growing power of Chinese companies. Zadek recently founded the “Sustainable Digital Finance Alliance” with Ant Financial, the first global public-private partnership with a private Chinese company. He hopes the platform will address worldwide social welfare, especially in Ant Financial’s overseas investments such as India’s PayTM online payment platform.

Private companies like Alipay have been the impetus of China’s recent economic growth, engraining themselves in people’s daily life by tapping into their needs and motivations. One reason for Ant Forest’s success, Zadek hypothesizes to TWOC, was that it met a need in society, giving young people the chance to make a social difference outside of a closed political sphere. (The numbers back him up—an estimated 65 percent of Ant Forest users are under 28). It is yet to be seen, however, how the government will engage with the growing financial and social power of these non state-owned companies.

Asked about future challenges of Ant Forest, Le ducked concerns about increased government oversight, and instead half-way joked: “Quite honestly, we are soon going to run out of places to plant trees.”