In a major step toward its carbon-negative goal, Microsoft has entered into a decade-long agreement with Arca, a Canadian climate technology company, to procure nearly 300,000 tons of durable carbon dioxide removal (CDR).
Arca specializes in industrial mineralization, a process that leverages existing heavy industrial infrastructure to repurpose alkaline waste streams, primarily mine tailings and waste rock.
The technology accelerates a natural geochemical process where atmospheric CO₂ binds with minerals and is permanently stored as stable, solid carbonate rock for millennia. The process has been scientifically proven and demonstrated at full scale at an active mine site in 2025.
Accelerating Microsoft’s climate goals:
The deal reflects Microsoft’s strategy to diversify its carbon removal portfolio with solutions that offer high scalability and permanence. Microsoft has committed to being carbon-negative by 2030 and removing all of its historical emissions by 2050.
Phil Goodman, Director, Carbon Dioxide Removal Program, Microsoft, noted that Arca’s notable scientific expertise and successful demonstration project provided the confidence needed for a multi-year commitment. This long-term contract is vital for Arca, as it fuels the company’s expansion from pilot projects to potential million-ton operations.
Turning waste into climate assets:
Arca’s approach offers significant co-benefits beyond climate change mitigation. By repurposing billions of tons of existing industrial waste, the solution effectively turns an environmental liability—mine tailings—into a climate asset.
Paul Needham, CEO, Arca, said, “We have a unique opportunity to utilize one form of waste (mine tailings) to neutralize another (excess atmospheric CO₂). The result is less waste and a healthier environment.” The process also uses minimal land, water, and energy and includes robust measurement, reporting, and verification (MRV) systems to ensure the transparency and durability of the carbon removal credits.
