Sigma Lithium claims that its mine in Brazil is “carbon neutral”. It bought REDD carbon credits from the Unitor REDD project, which is now suspended and accused of illegal logging
Ricardo Stoppe Júnior, the man behind the Unitor REDD project, is accused of selling about US$34 million illegal REDD credits.
Imagine this. A Canadian company is mining lithium in Brazil. The lithium is marketed as “carbon neutral” thanks to carbon credits from a REDD project in Brazil. The project developer of the REDD project is funded by a one of the biggest and most polluting oil corporations in the world.
Meanwhile, the man behind the REDD project has been fined several times by Brazil’s environmental agency, IBAMA, for illegal deforestation. In 2024, he was arrested as the leader of a criminal organisation accused of selling about US$34 million of allegedly illegal REDD credits.
You might think this is a work of climate fiction. It’s not.
Journalists Isabel Harari, Andrés Bermúdez Liévano, Kuek Ser Kuang Keng, Jelter Meers have documented the story in a brilliant piece of investigative journalism for Dialogue Earth. The article is part of the CLIP series “Lithium in conflict”.
Sigma Lithium
The Canadian mining company is Sigma Lithium. It describes itself as “leading global lithium producer dedicated to powering the next generation of electric vehicle batteries with carbon neutral, socially and environmentally sustainable chemical-grade lithium concentrate”.
Sigma Lithium has lithium mining operations in the Jequitinhonha Valley in north-eastern Minas Gerais. The company runs the Grota do Cirilo mine and the Greentech processing plant.
In July 2023, Sigma Lithium announced its first shipment of 30,000 tonnes of lithium and by-products. In a press release, Sigma explains that the shipment was “carbon neutral” because it had offset the “hard to abate” greenhouse gas emissions from its mine and its processing plant.
When the journalists asked Sigma about its carbon offsets, Sigma replied that it “has not used carbon credits since 2024”. Yet it still claims that its lithium is “zero carbon”.
Carbonext and Shell
Sigma bought 59,000 carbon credits from Carbonext, a Brazilian company that runs REDD projects in Brazil. In July 2022, Shell announced that it had invested US$38 million in Carbonext.
In a press release, Sigma stated that, “The carbon credits generated by Carbonext and its partners are of high quality and integrity.” Sigma added that the carbon credits “are certified by Verra, an international body specializing in this type of service”.
That press release came six months after an investigation by The Guardian, SourceMaterial, and Die Zeit revealed that more than 90% of carbon credits certified by Verra are worthless.
The journalists asked Sigma a series of follow up questions, including about the due diligence procedure Sigma used to assess the quality of the REDD project from which it sourced its carbon credits. Sigma did not reply.
Unitor REDD project
Sigma’s carbon credits were generated by the Unitor REDD project. Other companies that bought credits from the project include PwC International, Colombia’s state oil company Ecopetrol, the Austrian state oil company OMV, the Belgian chocolate company Guylian, and Belo Horizonte airport’s concessionaire.
The project was registered with Verra in 2022 by a Brazilian businessman called Ricardo Stoppe Júnior.
In 2023, Stoppe took part in COP28 in Dubai, where he called himself the “king of carbon credits”. In a presentation during COP28, Stoppe claimed that in 2023 his company had negotiated a 5 million carbon credit deal with the EU, and in 2024 it would produce 10 million carbon credits.
On 28 August 2023, one of Sigma’s Brazilian subsidiaries, Sigma Mineração SA, retired 59,000 credits. The reason for retiring the credits was given on Verra’s registry as “Environmental offsetting of greenhouse gas (‘GHG’) emissions related to Sigma Lithium’s annual production in Brazil.”
The Unitor REDD project consisted of 15 neighbouring farms in the Lábrea region of Amazonas State. The REDD project covered an area of almost 100,000 hectares of forest and according to project documents would generate an average of more than 400,000 carbon credits per year over the 30-year project period.
The project was supposed to stop deforestation of mature forests and stop illegal logging.
Ricardo Stoppe Júnior’s agricultural company Ituxi Administração e Participação Ltd was one of the landowners. A 2025 investigation by Reuters revealed that when Stoppe registered the Unitor REDD project with Verra in 2022, he and two other landowners involved in the project had been fined seven times by IBAMA. The fines totalled more than US$1.5 million. Among the offences were clearing rainforest and grazing cattle on deforested land.
After the Unitor REDD project was registered, Stoppe and his partners were fined 18 more times by IBAMA. The offences included clearing 42 square kilometres of forest and falsifying the origin of 180,000 cubic metres of timber.
In May 2022, despite these fines, the Unitor REDD project was validated by the Spanish auditor Aenor and certified by Verra.
Operation Greenwashing
Two years later, an investigation by Mongabay found inconsistencies between the volume of timber declared to authorities and the amount actually felled according to analysis of satellite images. The images were analysed by the Center for Climate Crime Analysis and the investigation was part of the Opaque Carbon project, led by CLIP.
A Verra spokesperson told Mongabay that it needed more details about the analyses before commenting on the findings.
Two weeks after Mongabay’s investigation was published, Brazil’s Federal Police launched Operation Greenwashing. The police were investigating links between land grabbing and illegal deforestation. Stoppe was among those arrested.
A week later, Verra suspended the Unitor project “until all findings are satisfactorily closed”. (Verra also suspended two of Stoppe’s other projects: the Fortaleza Ituxi REDD project; and the Evergreen REDD project.)
Carbonext told the journalists that it had written to Verra five days before the projects were suspended, to inform Verra of the police operation. Carbonext suspended “any sale, transfer, generation and issuance of credits from these project until further notice from the authorities”.
A 2024 legal recommendation from the Federal Public Ministry of Amazonas calls for the suspension of REDD projects in the state.
In October 2025, Folha de São Paulo reported that the Federal Police had completed two final reports that documented 31 people involved in a criminal organisation suspected of being involved in fraud and land grabbing aimed at generating carbon credits.
It is the largest carbon credit fraud case so far in Brazil.
The lead suspect, according to the police investigation is Ricardo Stoppe Júnior.
More than 1 million m³ was illegally logged. Almost 180 million carbon credits were sold.
The police have indicted Stoppe for corruption, deforestation on public land, crime against the financial system, invasion of public land, money laundering, and criminal organisation.
Stoppe is currently under electronic surveillance. The police reports have been sent to the Federal Public Prosecutor’s Office which will decide whether to bring the case to court.
“We breathe dust 24 hours a day”
The negative impact of lithium mining has been criticised by traditional peoples’ associations, civil society organisations, and public bodies.
In December 2024, Brazil’s Federal Public Prosecutor’s Office (MPF) warned of the high environmental impact of lithium mining. The Ministry’s ruling noted that lithium mining has “the potential to aggravate the vulnerability of traditional communities”. The ruling highlighted that in the case of Sigma, there is a “clear deficiency” in the granting of environmental licences.
A letter dated 21 August 2025, signed by 68 organisations, states that,
Since 2023, more than 100 families affected by the project suffer daily negative impacts, collective and individual damage, such as high noise levels, dust, cracks in their homes, health problems and losses in food production.
The Dialogue Earth journalists write that in September 2025, the MPF sent a recommendation to the National Mining Agency requesting the suspension and review of lithium exploration and extraction authorisations in Araçuaí, where Sigma operates.
The village of Piauí Poço Dantas is close to Sigma’s Grota do Cirilo mine. Villagers have reported increased noise as a result of the mine and cracks in their homes as a result of detonations in the mine.
“We breathe dust 24 hours a day,” a resident of Piauí Poço Dantas said.