HOW CLIMATE STARTUPS ARE TURNING CARBON INTO GOLD

A few startups are helping farmers turn crop residue, rice irrigation and soil chemistry into tradable carbon credits

- Shadma Shaikh

For Subhonanda Singha, a third-generation farmer in Dubanochi village, Darjeeling, rocks were something you cleared out of a field, not something you brought in by the truckload.

But for the last three cropping seasons, Singha has been spreading a thin layer of grey basalt powder over his paddy fields.

The basalt dust disappears once a tractor folds it into the soil. In Singha's field, it looks like soil treatment. But in a corporate climate report generated thousands of kilometres away, it is logged as carbon removal.

Singha's improved yield after spreading the basalt dust, called Hari Mati, is not part of any government programme. The material is supplied free of cost by Bengaluru-based climate tech startup Alt Carbon, which sources it from quarry and mining waste in eastern India and distributes it to nearby farms.

Each verified tonne of CO2 removed from a field like Singha's becomes a carbon credit, which global corporations currently buy for roughly $150 to $600 per tonne, depending on durability and technology. In a way, carbon credits are financial instruments designed to channel capital from developed economies that are responsible for a larger share of historical emissions into developing countries that are often more exposed to climate impacts. Such credits allow companies to offset emissions by funding verified environmental projects. One carbon credit is roughly equivalent to the emissions caused from burning about 430 litres of petrol or around-trip flight between Delhi and Singapore. It can sometimes take more than a year for a carbon credit to be issued. Startups are now emerging to organize this long chain of geology, farming and carbon accounting.