Their Galvanize Climate Solutions was joined in the $38 million Series B fundraising by Salesforce founder Marc Benioff's TIME Ventures and Rethink Impact, alongside existing investors including trader Cargill and Microsoft's M12.
Food and agriculture contributes 26% of the world's total carbon emissions, Regrow says, and is a growing area of focus for companies as they look to reduce their own emissions by greening their supply chains.
To help fix the problem, Regrow, a software-as-a-service (SaaS) company, connects companies and others with farmers, who enrol in various programmes that pay them for adopting farming practices that reduce emissions, preserve soil quality and minimise use of chemicals.
"Agriculture needs resilience not just to put food on our plates today, but to support a liveable planet for future generations," said Regrow co-founder and chief executive Anastasia Volkova.
Such farming techniques in many cases involve reverting to more traditional practices, common before the advent of industrial-scale farming, but at a cost that many farmers are unwilling to take without financial help.
Companies and others keen to see it happen, such as state-backed institutions, meanwhile, want to be sure they are getting what they pay for and not wasting money on a farmer who hasn't actually changed methods and cut emissions.
Markets for carbon captured and stored in agricultural soils have struggled to scale up due to systemic problems with measuring their climate benefit and questions about the permanence of carbon captured by intensive row crop farming.
Global croplands and grasslands can capture and store the equivalent of up to 8.6 gigatons of carbon dioxide a year, according to a 2019 report from the Intergovernmental Panel on Climate Change.
Regrow's technology platform allows farmers to establish a baseline for their carbon emissions and then estimate the likely savings by changing certain practices, such as by tilling the fields less or by introducing livestock to the farm.
After agreeing to make the changes, Regrow uses satellite imaging and remote sensing to check the emissions have been reduced, giving greater assurance to the buyers of the carbon credits that are created as a result.
(This story corrects spelling of Steyer in headline and first paragraph.)
(Reporting by Simon Jessop and Karl Plume; Editing by MarkPotter)
By Simon Jessop and Karl Plume