(Bloomberg) -- Stripe Inc.’s $1 billion Frontier fund has written its third round of checks to startups attempting to suck carbon dioxide out of the atmosphere. 

Frontier facilitated the purchase of $7 million of carbon removal services from 12 startups on behalf of Stripe — which initiated the fund — Shopify Inc. and Hennes & Mauritz AB (H&M). The startups use a variety of techniques to remove carbon from the air. Among them are CarbonRun, which changes the alkalinity of rivers to enhance their natural ability to remove CO2, and Banyu Carbon, which uses sunlight to pull CO2 from seawater. A number of companies remove carbon from the ambient air using machines, a process known as direct air capture. 

The diversity of approaches to carbon removal shows the industry is still at an early stage, with no clear-cut winner for taking carbon from the atmosphere yet. Since it was launched in 2022, Frontier has facilitated the purchase of carbon removal from 27 that use a range of carbon removal techniques. The group has also doled out five R&D grants. While it hopes that some, if not all of them, work as promised, Frontier is creating a “risk-adjusted portfolio,” according to Joanna Klitzke, the group’s procurement and ecosystem strategy lead. Doing so accounts for the technical challenges that various means of durable carbon removal face.

“Our view is we need as many shots on goal today to be able to get to that portfolio,” she added.

Founded by Stripe, Alphabet Inc.,  Meta Platforms Inc., McKinsey Sustainability and Shopify, Frontier has committed to spend $1 billion on carbon removal by 2030. The fund has arranged for the purchase of about $65.9 million in carbon removal services since its inception, amounting to 131,000 tons of CO2. Scientists estimate the world will need to remove billions of tons of CO2 annually by midcentury in order to meet climate goals. 

“Recognizing and supporting the potential of new and innovative solutions in their early stages of development, and the climate entrepreneurs behind them, is critical because no solution will single-handedly reverse climate change,” said Stacy Kauk, head of sustainability at Shopify, in an emailed statement. 

Frontier is an advance market commitment, which means that the funds going towards this cohort of startups are pre-purchases made in advance of them actually removing CO2. The goal is to jumpstart the nascent carbon removal market, by signaling demand and spurring new supply. So far, only a handful of startups backed by Frontier have successfully removed CO2 from the atmosphere, and the ones that have have done so on a small scale. 

“We’ve seen a number of companies able to unlock significant financing after our purchase or companies speeding up their technological or research roadmaps as a result,” Klitzke said. “This is a really high-impact way to push forward their trajectory.” 

(Updates paragraph 2 with clarifying information about Stripe’s role in Frontier.)

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