Running Tide ocean carbon removal (Maine/Iceland)
- Researchers Jón Ólafsson, Icelandic oceanographer: "The methods used by Running Tide do not sequester any carbon dioxide from the atmosphere. Zero." REDD-Monitor
- Company or project Marty Odlin, Running Tide: "We did the thing … We removed carbon." He called the Heimildin article "absurd". Sun Journal
- Press and investigations Canary Media, citing a former executive: About half the carbon in the first deployment's wood was spent in operations. Canary Media
- Press and investigations MIT Technology Review: Five scientists left, citing in part concern about ecological effects; a patent describes iron-oxide release, which could amount to ocean fertilisation. MIT Technology Review
- Company or project Marty Odlin, Running Tide: "We have a commitment to science and take seriously our stewardship of the oceans." Turnover was "remarkably low". MIT Technology Review
- Researchers Philip Boyd: "We have no idea what happens when we scale this up." MIT Technology Review
A Maine company sold ocean carbon-removal credits to corporate buyers and sank wood chips off Iceland. An Icelandic oceanographer said the method captured no atmospheric carbon; the company said it had removed carbon. It closed in June 2024.
Measurement was the company's own; the company said delivering independently certified credits was not its goal.
Status As of the latest reporting reviewed (June–July 2024 on the shutdown; a WIRED report of December 2025 could not be checked): the company has closed; no refunds, independent verification, ruling or penalty were found.
- Credit buyers (Microsoft, Shopify, Stripe and others) — Received ocean carbon-removal credits that no independent party has verified; Shopify publicised its "first ever ocean-based carbon removal credits". Trellis
- Running Tide — Sold credits at a list price of $250–350 per tonne; revenue was never disclosed.
- Marty Odlin, founder — Bought back what remained of the company from investors after the shutdown. Canary Media
- Investors, including Lowercarbon Capital — Lost about $54 million or more of capital (per Canary Media's buy-back report). Canary Media
- Employees — The last 32 US employees were laid off without severance, plus 15 in Iceland. Portland Press Herald
- Seabed and coastal waters off Iceland — Received about 19,000 tonnes of lime-coated wood chips at about 1,600 m; no ecological impact study was run beforehand and no seabed outcome has been published. REDD-Monitor
What happened
Running Tide was founded in 2017 in Portland, Maine, by Marty Odlin, who had previously run his family's groundfishing fleet. It proposed free-floating kelp "microfarms" on biodegradable buoys made of wood coated in limestone, which would float for six to eight months and then sink below 1,000 metres. Its stated aim was to remove 1 billion tonnes of carbon dioxide a year; MIT Technology Review reported a goal of "1 billion tons of carbon dioxide by 2025".
Running Tide raised a $54 million Series B in early 2022, led by Lowercarbon Capital, with other investors including Foobar, Greenpoint Partners, Grantham, Foundry Group and Venrock; the Portland Press Herald put its funding at more than $50 million. In summer 2023, about 1,000 investor meetings failed to raise a growth round, and a former executive said the company's roadmap had assumed about $1 billion to leave research and development. The company sold credits to corporate buyers. Heimildin, as summarised by REDD-Monitor, reported that Microsoft was listed at 12,000 credits and Shopify at 3,100, and that about 25,000 credits were sold in total. The company's list price was $250–350 per tonne, which it told Reuters in August 2023. Revenue was not disclosed.
In June 2022, MIT Technology Review reported that Running Tide had struggled to grow kelp on open-ocean ropes and that five scientists had left, citing in part concern about ecological effects; it also reported that a company patent described iron-oxide release, which could amount to ocean fertilisation. The company's 2023 Iceland deployment did not use kelp buoys. Instead it dumped wood chips coated with lime-kiln dust (calcium carbonate) to a depth of about 1,600 metres. Heimildin, in June 2024, put the volume at about 19,000 tonnes, or 15 barges, of Canadian wood chips. A former executive told Canary Media that about half of the carbon in the first deployment's wood was spent in the operations themselves, and that no ecological impact studies were run beforehand.
In December 2022 Iceland's environment ministry ruled that a permit was required to dump tens of thousands of tonnes of wood chips. Running Tide appealed; the environment minister recused himself, and acting minister Bjarni Benediktsson ruled in April 2023 that the activity was a research project. Iceland's Environment Agency had no oversight of the operations and said there was "significant uncertainty" about results and environmental impact. Icelandic oceanographer Jón Ólafsson said the methods "do not sequester any carbon dioxide from the atmosphere. Zero." Odlin called the Heimildin article "absurd" and said "We did the thing … We removed carbon." He also said it "was not the company's goal to deliver to customers carbon units that were certified by an independent party that could be used for carbon offsets."
Running Tide announced its shutdown on LinkedIn on 14 June 2024, saying it was "unable to secure the right kind of financing". Odlin added: "The voluntary carbon market is voluntary, and there simply isn't the demand needed." The last 32 US employees were laid off without severance, along with 15 in Iceland; layoffs had begun in November 2023. Odlin bought back what remained of the company from investors, according to Canary Media, and four staff continued the work. No refunds or cancellations for credit buyers were reported.
- 2017Running Tide founded in Portland, Maine, by Marty Odlin
- 2022Series B of $54 million, led by Lowercarbon Capital (early 2022); MIT Technology Review reports scientist departures and ecological concerns (June); Iceland's environment ministry rules a permit is required (December)
- 2023Acting minister Bjarni Benediktsson rules the Iceland dumping a research project (April); Iceland deployment of lime-coated wood chips to about 1,600 m; Shopify video on its "first ever ocean-based carbon removal credits" (9 August); partnership with Ocean Networks Canada announced (September); layoffs begin (November)
- 2024Shutdown announced on LinkedIn (14 June); Heimildin reports on the wood-chip dumping (June); REDD-Monitor summary (3 July); the last 32 US staff laid off without severance
What was said
“We have a commitment to science and take seriously our stewardship of the oceans.”
“We have no idea what happens when we scale this up.”
“The methods used by Running Tide do not sequester any carbon dioxide from the atmosphere. Zero.”
“There is no reason to sink such a large amount.”
“It's amazing how out of control this field is.”
“They're trying to make a controversy out of us approaching this as professional engineers.”
“We did the thing … We removed carbon.”
“The units we deliver are not emission allowances but on the optional market.”
“The voluntary carbon market is voluntary, and there simply isn't the demand needed.”
Where accounts differ
Each party's account, side by side, with its source. The record does not settle these points; it shows them.
"The methods used by Running Tide do not sequester any carbon dioxide from the atmosphere. Zero."
REDD-Monitor"We did the thing … We removed carbon." He called the Heimildin article "absurd".
Sun JournalAbout half the carbon in the first deployment's wood was spent in operations.
Canary MediaRuled in December 2022 that a permit was required to dump tens of thousands of tonnes of wood chips.
Appealed the ruling.
Ruled in April 2023, after the environment minister recused himself, that the activity was a research project.
REDD-MonitorHad no oversight of the operations and said there was "significant uncertainty" about results and environmental impact.
Five scientists left, citing in part concern about ecological effects; a patent describes iron-oxide release, which could amount to ocean fertilisation.
MIT Technology Review"We have a commitment to science and take seriously our stewardship of the oceans." Turnover was "remarkably low".
MIT Technology ReviewDelivering carbon units certified by an independent party "was not the company's goal".
Buyers hold credits that no independent party has verified; no refunds or cancellations were reported.
TrellisDid not reply to Heimildin's questions; Microsoft declined to answer questions.
TrellisHow it looked
Shown
- Free-floating kelp microfarms on biodegradable wood buoys coated in limestone, sinking below 1,000 m after six to eight months; aim of 1 billion tonnes of CO2 a year.Running Tide, as reported by MIT Technology Review
- In 2023 the company announced it had completed its first open-ocean carbon removal: 1,000 tonnes of waste wood sunk, with a net effect of 275 tonnes of CO2.Running Tide
- "Our first ever ocean-based carbon removal credits", in a video of 9 August 2023.Shopify
Recorded
- The 2023 Iceland deployment used wood chips coated with lime-kiln dust or calcium carbonate, dumped about 1,600 m deep, not kelp buoys. Heimildin put the volume at about 19,000 tonnes, or 15 barges, of Canadian wood chips.
- June 2022: Running Tide struggled to grow kelp on open-ocean ropes; five scientists left, citing in part concern about ecological effects; a patent describes iron-oxide release, which could amount to ocean fertilisation.
- A former executive said about half the carbon in the first deployment's wood was spent in operations. No ecological impact studies were run beforehand.
- Acting minister Bjarni Benediktsson ruled in April 2023 that the Iceland dumping was a research project.
- Iceland's Environment Agency had no oversight of the operations and said there was "significant uncertainty" about results and environmental impact.
- No measured seabed outcome has been published. A September 2023 partnership with Ocean Networks Canada was to observe the buoys.
- No refunds or cancellations for credit buyers were reported; buyers hold credits that no independent party has verified.
- Ship charters in Iceland cost $20,000–50,000 a day; operations ran from Akranes and Grundartangi with 15 local staff.
Who gained
Reached nature or the ground
Gained elsewhere
Responses on record
- running-tide (17 June 2024): Marty Odlin called the Heimildin article "absurd". · Sun Journal
- running-tide (2024): Odlin said it "was not the company's goal to deliver to customers carbon units that were certified by an independent party that could be used for carbon offsets."
- running-tide (June 2022): Odlin said of the departures of scientists that turnover was "remarkably low", and that kelp "yield and consistency are not yet commensurate with that needed for large-scale carbon removal." · MIT Technology Review
- microsoft (2023–2024): Declined to comment on the price of its deal; declined to answer questions; did not reply to Heimildin. · Trellis
- shopify (2024): Did not reply to Heimildin's questions about the credits. · Trellis
- stripe (2024): Did not reply to Heimildin's questions about the credits. · Trellis
- iceland-environment-agency (2023): Said there was "significant uncertainty" about the results and environmental impact of the dumping.
- iceland-environment-ministry (December 2022 – April 2023): Ruled in December 2022 that a permit was required; acting minister Bjarni Benediktsson ruled in April 2023 that the activity was a research project. · REDD-Monitor
In court and with insurers
Lawsuits and rulings
Insurers
What nature saw
Nature's report opens this page. Below: further outcomes measured on the ground.
What we don't know
Nature
- Not measured Harm to nature: No independent ecological evaluation is on record.
- Disputed Did sinking wood chips remove carbon from the atmosphere?
- Disputed Did the company's methods carry ecological risk?
Court
- None on record No court case on record.
Figures
- Insufficient Tonnes claimed removed: Company claim of deep-ocean storage, relayed in secondary summaries of its March 2024 release; not independently verified.
Accounts
- Disputed Did the Iceland dumping need a permit?
- Disputed What did buyers receive, and were the credits independently verified?
- None on record Microsoft, Shopify, Stripe: Did not reply to Heimildin's questions; Microsoft declined to answer questions.
Record
- None on record Revenue: never disclosed. The research's estimate of $5.3–7.4 million gross assumes the list price applied to about 21,000 tonnes.
- Not disclosed Price of the Microsoft deal: Microsoft declined to comment on price.
- None on record No measured seabed outcome from the Iceland deployment has been published.
- None on record No independent verifier or credit registry covers the credits.
- Disputed Total wood chips dumped: figures differ between sources, from 19,000 to 50,000 tonnes.
- None on record Shopify's tonnage: Heimildin cited Shopify's 2023 sustainability report as showing 3,100 credits bought; a secondary summary of the company's March 2024 release listed 2,000 tonnes. Both are reported, neither independently verified here.
- Insufficient Reported but not independently verified: WIRED (December 2025) reportedly gave about 25,000 tonnes of wood chips and said ship-tracking data indicates the company likely violated the maritime rights of several countries; the article could not be opened.
- Insufficient Reported but not independently verified: the company's claim of about 21,000 tonnes stored in the deep ocean for more than 25 customers, and buyer tonnages other than Microsoft's and Shopify's, come from secondary summaries of its March 2024 release.
- None on record No penalty or criminal record against the company was found.
Did the harm stop?
The company announced its shutdown on 14 June 2024. No measured seabed outcome from the 2023 dumping has been published.
Who paid?
Investors lost their capital (about $54 million or more, per Canary Media); the last 32 US employees were laid off without severance, plus 15 in Iceland; buyers hold credits that no independent party has verified.
Sources
Press and investigations
- Article on Running Tide scientist departures and ecological concernsMIT Technology Review · 2022-06-16
- Sun Journal report quoting Marty Odlin on the Heimildin articleSun Journal · 2024-06-17
- Portland Press Herald report on Running Tide's funding and layoffsPortland Press Herald ·
- Running Tide's final yearLatitude Media ·
Communities and civil society
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