Microsoft has entered into agreement with Enhanced Rock Weathering (ERW) company Terradot to remove 12,000 tons of CO2 between 2026 and 2029.
The agreement is Microsoft's fourth with an ERW company, having previously inked deals with Undo to remove 15,000 tons, Eion to remove 8,000 tons, and Lithos Carbon to remove 11,400 tons.
"This agreement with Microsoft represents a critical step forward in our mission to transform enhanced rock weathering into a cornerstone of global carbon removal efforts," said James Kanoff, CEO of Terradot.
ERW works by speeding up the natural process of carbon removal when rainwater interacts with silicate rocks. This is done by crushing tons of silicate rocks into a powder and spreading it onto farmland to accelerate rock dissolution rates. Subsequently, when it rains, the rocks react, generating alkalinity, which pulls CO2 out of the atmosphere and into water as a bicarbonate byproduct.
The agreement will also provide funding to conduct what Terradot says will be the most comprehensive scientific monitoring ever implemented at a commercial ERW site.
The company boasts that its expanded scientific monitoring goes significantly beyond current registry protocols to answer fundamental questions about how ERW truly impacts natural systems.
The process includes enhanced sampling density, and advanced water system and watershed monitoring, which it says will improve carbon cycle analysis and advance the models used in ERW validation.
"The research we're conducting will serve two critical functions," said Professor Scott Fendorf of Stanford University and a founding member of Terradot's science team.
"First, it will build trust and confidence in ERW measurement, reporting, and verification – not just for Terradot but for the industry as a whole – giving buyers even more confidence that ERW can meet urgent carbon removal needs. Second, the data will enable Terradot to develop incredibly low-cost MRV approaches that will allow us to scale to meet the growing customer demand created by increased confidence in ERW as a gold standard of carbon removal. It’s a win-win.”
Terradot has already implemented the monitoring protocol in Brazil, where it has spread nearly 50,000 tons of rock across 2,000 hectares of land. The first carbon credits tied to the project are expected to be delivered in late 2025.
According to Julia Marisa Sekula, Terradot's chief financial officer and director of Brazil Operations: "Brazil's unique combination of tropical soils, clean electricity grid, and agricultural infrastructure makes it an ideal location for scaling ERW."
Terradot was founded at Stanford University in 2022. It has already signed agreements to remove almost 300,000 tons of CO2 through its ERW process. This includes a 200,000 ton removal agreement with Google, to be delivered in the early 2030s. It also includes a $33 million agreement with the carbon buying consortium Frontier, which counts Alphabet and Meta as founding members. The Frontier deal will see its buyers secure the removal of 78,707 tons of CO2 between 2027 and 2030.
In addition, in December, the startup announced that it had secured $58.2 million in Series A funding from a range of investors, including Microsoft’s Climate Innovation Fund and Google.
Microsoft has also invested in a range of other carbon removal processes. So far in 2025, it has signed agreements with three afforestation firms. These include an agreement to remove 1.5 million tons of CO2 in India, a 25-year agreement with Chestnut Carbon to purchase seven million carbon credits and another 25-year deal in Brazil with Re.green to purchase 3.5 million credits.
Microsoft is the biggest corporate purchaser of carbon removal in the world. Last year it led the market with 5.1 million tons, a 63 percent share in the entire market. It has committed to be carbon negative by 2030 and by 2050 have removed all the carbon the company has emitted either directly or by electrical consumption since its founding in 1975.
