Microsoft taps Alt Carbon in sign of India’s growing role in carbon removal

In a landmark move, Microsoft has entered into a three-year agreement with Alt Carbon, an innovative startup from India, to procure nearly 37,000 tons of carbon removal credits. This partnership represents the tech giant's inaugural enhanced rock weathering agreement in Asia, focusing on sustainability and environmental responsibility. Under the terms of the deal, Alt Carbon will supply 36,920 metric tons of carbon dioxide removal credits by 2029, sourced from its ambitious Darjeeling Revival Project located in eastern India. Notably, Microsoft retains the option to acquire additional credits, contingent upon Alt Carbon meeting specific delivery and verification milestones. This agreement comes at a time when there have been rumors regarding a slowdown in Microsoft's carbon-removal procurement initiatives. However, the company has firmly denied these claims, reaffirming its dedication to climate objectives while refining its sustainability strategies. For Alt Carbon, which was established in Bengaluru in 2023, this collaboration is a significant opportunity, allowing it to enhance its carbon removal projects that utilize the technique of enhanced rock weathering. The process involves distributing crushed basalt and other silicate rocks across agricultural lands to accelerate natural chemical reactions that capture carbon dioxide. Alt Carbon sources basalt from the Rajmahal Traps in eastern India and spreads it on farmland in West Bengal, where it interacts with rainwater and atmospheric carbon to create stable bicarbonates. According to Sparsh Agarwal, the co-founder and President of Alt Carbon, discussions with Microsoft commenced in early 2025 and progressed over a year, culminating after thorough scientific evaluations and extensive contract negotiations. Microsoft also insisted on additional monitoring and verification measures that go beyond standard registry protocols, requiring enhanced data sharing and precise carbon quantification methods. As the demand for reliable carbon removal projects escalates, the market faces a scarcity of verified supply. Although numerous startups claim to offer carbon removal solutions, only a limited number have been able to deliver verified credits at a commercial scale. Agarwal highlighted the challenge: "While there are many suppliers, the verified deliveries are few. Companies are eager to secure a portion of the available supply." Currently, Alt Carbon has issued nearly 10,000 carbon removal credits through enhanced rock weathering, marking it as a leader in this emerging field. The startup anticipates issuing an additional 15,000 credits by the end of the year and operates two carbon removal projects in North Bengal, one of which is dedicated to the Japanese shipping company Mitsui OSK Lines. Furthermore, credits generated under the Microsoft agreement will be recorded through Isometric, a carbon-removal registry that has developed a specific methodology for enhanced rock weathering. This collaboration underscores the increasing significance of emerging market suppliers in the carbon removal landscape, with developers from the Global South accounting for approximately 26% of carbon-removal credit issuances, a substantial rise from around 2% in 2022. Although skepticism initially surrounded Indian carbon projects, the growing volume of issued credits and stringent verification standards have fostered greater confidence among international buyers. Notably, this is not Microsoft's first foray into carbon removal in India; earlier this year, it also partnered with another startup, Varaha, to acquire over 100,000 tons of biochar-generated carbon dioxide removal credits. As demand for verified carbon removal credits continues to grow, Alt Carbon is poised for expansion, aiming to scale its operational footprint fivefold in the next four to five years. Having secured $12 million in seed funding last year, Alt Carbon has established its own monitoring and verification infrastructure, including labs in Bengaluru and Darjeeling, to analyze soil and water samples and accurately quantify carbon removal. Agarwal emphasized the importance of improving verification capabilities and reducing measurement costs to successfully scale enhanced rock weathering initiatives both in India and globally.