AltCarbon, a climate tech startup, has scaled an enhanced rock weathering project from a 300 acre tea estate in Darjeeling to 60,000 acres across North Bengal, working with over 35,000 farmers. The company spreads crushed basalt on farmland to accelerate natural CO2 absorption, locking carbon in the ocean for thousands of years. Clients include Microsoft and Google, and AltCarbon aims to remove 5 million tonnes of CO2 by 2030. The founders, Sparsh and Shrey Agarwal, built their own labs after finding India lacked scientific infrastructure for carbon removal. They now run two labs and a team of 45, mostly scientists. The project uses India's tropical climate and Himalayan geology to speed up silicate weathering. AltCarbon sells carbon credits to tech companies, but the founders admit the science is young and projections are uncertain. The article is worth reading for a grounded look at how enhanced rock weathering is being deployed in a real agricultural setting, with honest discussion of the challenges.
