Alt Carbon Raises $12M to Scale Carbon Removal in India

Climate tech startup Alt Carbon has secured $12 million in seed funding to expand its carbon dioxide removal operations in India. The company uses enhanced rock weathering, a process that locks away carbon for millennia.

The funding round was led by Lachy Groom, co-founder of robotics AI company Physical Intelligence. Alt Carbon plans to use the investment to scale its operations across 500,000 hectares of farmland.

From Tea Estate to Climate Innovation

Founded in late 2023 by siblings Shrey and Sparsh Agarwal, Alt Carbon's origins lie in their family's struggling tea estate in Darjeeling. Seeking a solution, they discovered enhanced rock weathering as a way to generate income and address climate change.

“Within carbon markets, our realization was that a lot of the projects in India, which are more avoidance-based, are of very low quality, and they produce junk credits,” Sparsh Agarwal explained.

How Enhanced Rock Weathering Works

Alt Carbon spreads basalt rock dust, a byproduct of mining, onto farmlands. Rainwater reacts with the basalt, capturing carbon dioxide and forming stable bicarbonate ions. These ions are stored in the soil and eventually reach the ocean, where they become calcium carbonate, effectively locking away carbon for over 10,000 years.

This process also enriches the soil with micronutrients, improving fertility and crop yields. Alt Carbon combines the basalt with organic ingredients, creating a product called Hari Maati (green soil in Hindi) to encourage farmer adoption.

Scaling Carbon Removal and Measuring Impact

Alt Carbon began its pilot program on 500 acres around the family tea estate and has since expanded across North Bengal, including rice and bamboo farms. The startup aims to remove 5 million tons of carbon from the region by 2030.

To measure carbon removal, Alt Carbon uses a three-tiered approach:

  • Tracking weathering progress
  • Measuring soil water, groundwater, and river composition
  • Employing proprietary reactive transport models and machine learning

The company's models align with methodologies from carbon removal registries like Isometric and Puro.earth and have received approvals from organizations like SBTi, ICVCM, and CORSIA.

Partnerships and Future Growth

Alt Carbon has already secured a $500,000 pre-purchase from Frontier and participates in a $1 billion advanced market commitment led by Stripe, Alphabet, Meta, Shopify, and McKinsey. They have also partnered with NextGen, a buyer coalition including South Pole, Mitsubishi Corporation, and others, to scale their efforts.

The company will issue its first carbon credits through Isometric within the next month.