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Shopify, startup Running Tide tout ocean carbon removal breakthrough

Over the past 3 months after working on this project for 6 years, ocean carbon sequestration startup Running Tide sank 1000 tons wooden buoys off the Icelandic coast to prevent the embodied CO2 from being released into the atmosphere.

Man leading over pier

Running Tide working on a test buoy. Image courtesy of Jennifer Johnson/ Running Tide.

Ocean carbon sequestration trailblazer Running Tide announced Wednesday that it has delivered its first set of carbon removal credits to commerce technology company Shopify. 

Under the transaction, Shopify is receiving 100 of the 275 net metric tons of CO2 emissions removal credits created by sinking 1000 tons limestone-treated wood buoys a mile deep into the ocean about 200 miles off the coast of Iceland, according to the companies. The wood was taken from forestry trimming operations in Canada and Europe — where it would have been burned, releasing its carbon dioxide into the atmosphere. 

This is the first time this type of carbon sequestration has been tested and audited. Running Tide has been working on Shopify’s behalf since 2020, when it became part of the company’s Sustainability Fund, an initiative backing carbon removal entrepreneurs. This amount of removal is barely a drop in the bucket in terms of global emissions and is on the small side for a corporate carbon removal purchase. However, the project represents a novel method that is still being tested.

Deloitte was the official third-party verifier for the deal, but the normal avenues for verification weren’t available because there are no projects for comparison, according to the companies. Instead, the calculations for determining how many carbon removal credits should be issued were verified using a methodology developed by Running Tide and Shopify. The companies intend to share that framework for consideration by other ocean carbon removal solution providers, and this is the start of those processes, said Stacy Kauk, head of sustainability for Shopify.

"This is a big-time learning opportunity," Kauk said. "We want to make sure as many experts as possible are putting their eyes on this so that it can be improved and iterated on and be better next time. It's about the scientific experts getting their eyes on this." 

Moving out of the fast lane 

By sinking the biomass buoys into the ocean, Running Tide and Shopify claim that they have stored the CO2 embodied in the materials for thousands of years — instead of letting it decompose or be burned on land, where it would wind up in the atmosphere more quickly. According to Running Tide, the formula used to calculate the total amount of sequestered carbon reflects the weight of the sunk wood and the amount of limestone dissolved (observed via cameras), which removes carbon and also combats ocean acidification.

Running Tide CEO Marty Odlin said his company’s approach helps move CO2 from "fast" carbon cycles into a "slow" carbon cycle. In fast cycles, atmospheric carbon dioxide is absorbed by plants and then emitted again over the course of days, months or years — think of fruit growing, ripening, falling off and decomposing. Slow cycle moves carbon underground or into the ocean where they are stored for hundreds or thousands of years and turn into substances such as oil, coal and other minerals that can store carbon for much longer — if not burned by humans 

"From the best available science, which is what we operate on, we have achieved a high degree of permanence and low risk of reversal [for the carbon]," Odlin said.

Test bouy

Running Tide's wood buoy. Image courtesy of Jennifer Johnson/ Running Tide.

Running Tide has explored an ocean sequestration process that involves growing and sinking algae, but for this first project with Shopify only terrestrial wood was sunk. The company, based in Portland, Maine, runs a research and deployment center in Grundartangi, Iceland. It worked with the Icelandic government to get the research permits for its carbon sinking work. The startup has had five funding rounds from investors including Wells Fargo Innovation Incubator and Yes VC. Stripe, the Chan Zuckerberg Initiative and Microsoft also have made advance commitments to buy carbon removal credits from Running Tide.

Ecological uncertainties

The biggest question mark for Running Tide isn’t how much carbon will be stored, but the impact that sinking the terrestrial material could have on the ocean’s ecosystem.

Some scientific skeptics worry that Running Tide’s interventions could "harm highly complex, interconnected and delicate ecosystems," according to an MIT Technology Review article. Odlin said Running Tide has been guided by scientists and research models that have tested the process of sinking biomass along coastlines and shown little negative impacts on ocean ecosystems.

There's only one ocean. If you mess it up, we don't have a backup plan. At the same time, we can have caution and then we can also have a sense of urgency.

"We know that this is a form of carbon removal that the Earth naturally does," he said. "We know that rivers, especially in the past, transport a tremendous amount of material out into the open ocean. But with dams and farming, it’s been reduced."

However, Running Tide is not monitoring the exact ecosystems where it is dropping its buoys, because the small-scale nature of its current work makes it difficult to measure exact impacts. 

All hands on deck to validate and verify 

Sifang Chen, ocean carbon dioxide removal lead at nonprofit Carbon180, said ocean carbon sequestration startups such as Running Tide should prioritize validating their methodology and researching the ecological impact of their approaches by scaling up slowly.

"I think we should be cautious," Chen said. "There's only one ocean. If you mess it up, we don't have a backup plan. At the same time, we can have caution and then we can also have a sense of urgency. They don't have to be a zero-sum game. They don't have to be in conflict with each other."

Chen and her colleague Charlotte Levy, the managing advisor of science and innovation at Carbon180, stressed that what they want to see from Running Tide is verification and data transparency — metrics that can help inform the broader community working on carbon removal solutions and help ensure the activity is equitable, just and safe for the ocean. That is what will lead to confidence that these carbon removal claims are real and making positive impacts with no unintended consequences, they said. 

"I hope this is an opportunity for academic collaboration," Levy said. "We haven't had a chance to do that many experiments about what it would be like to add carbon [to the ocean] or change the pH [of the ocean]. This is an opportunity to find that out. We just shouldn't miss that. We should have lots of chances to share that data and get a lot of input on it."


Correction: The amount of credits Shopify is retiring has been adjusted. The amount of buoys Running Tide sunk is 1000 tons.

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