Inside the remarkable journey of a tonne of carbon, from Indian fields to corporate ledgers

carbon credit is roughly equivalent to the emissions caused from burning about 430 litres of petrol or a round-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.Alt Carbon was founded in 2023 by Sparsh Agarwal and his brother Shrey, who saw an unusual opportunity in India’s geology and climate. “If durable carbon removal is going to scale, it has to work in places where agricultural land and minerals are abundant, with ideal weather conditions,” says Agarwal, who is the chief executive of Alt Carbon.For farmers like Singha, the effects are more visible and immediate.

A few seasons ago, his land yielded 1,600-1,700kg of paddy per acre. After three crop cycles using basalt blended with organic manure, his production has risen to around 2,600kg per acre from the same field.

His family is among nearly 500 in the village who now participate in the programme.This small agronomic tweak is part of a much larger experiment of turning millions of small farms in the Global South into distributed carbon removal infrastructure, where the physical work will happen in muddy fields and the financial instrument will travel halfway around the world.Many of the world’s largest corporations, including Amazon, Microsoft, Google and Unilever, have pledged to reach “net zero” emissions between 2030 and 2040.For companies that run vast data centres, shipping fleets or global supply chains, annual emissions can run into millions of tonnes. Net zero means completely negating the amount of emissions, either by reducing them or implementing methods to absorb carbon dioxide from the