JASON
ARAMBURU

Dirt, fire, and a
20-year obsession

In Panama, an undergraduate was studying how ants pick their nesting sites based on soil composition. He stumbled onto something old - thousands of years old. The indigenous farmers of the Amazon basin had been burying charcoal in their fields long before anyone knew why. The soil they left behind, called terra preta, is still extraordinary today. Jason Aramburu could not let it go.

That Princeton research trip in the early 2000s planted a seed that has now grown into Applied Carbon: a Houston-based climate technology company building the world's first mobile, in-field machines that convert agricultural crop waste into biochar, a stable mineral form of carbon that can remain locked in soil for hundreds of thousands - possibly millions - of years. The machines look like a cross between a combine harvester and an industrial furnace on wheels. They drive through cornfields at 1 to 2 mph, pick up corn stover, heat it to 1,472 degrees Fahrenheit inside a closed, low-oxygen chamber, and deposit biochar back into the soil in a single pass. Total conversion time: about two minutes per batch.

Aramburu did not arrive here in a straight line. After Princeton, he trained smallholder farmers in Kenya how to make biochar with simple locally-made kilns, funded by the Bill and Melinda Gates Foundation. He founded re:char in 2009, bringing charcoal-based soil amendments to thousands of East African farmers. Then he pivoted: Edyn, a Wi-Fi-enabled soil probe and smart irrigation system, sailed through Y Combinator's Winter 2014 batch and blew past its Kickstarter goal in two weeks. Then came a stint at Baidu Ventures investing in early-stage AI. Then Saudi Aramco Energy Ventures, where he rose from investment principal to investment director and closed deals including Energy Vault - a company that went public at unicorn valuation in 2022.

The detour looked like a departure. It was not. When Aramburu co-founded what is now Applied Carbon with Dr. Morgan Williams - a UC Berkeley soil scientist he had first met at a biochar academic conference a decade earlier - he brought the full stack: field ecology, smallholder agriculture, robotics, AI, corporate finance, venture capital. "We don't want to be a huge company running pyrolizers all over the world," he has said. "More like a carbon-negative John Deere."

The machine is already running in Texas and Mississippi. The company rebranded from Climate Robotics to Applied Carbon in June 2024, then in July announced a $21.5M Series A led by TO.VC, with co-investors including Microsoft Climate Innovation Fund, Congruent Ventures, the Grantham Foundation, S2G Ventures, and eight others. In September, Applied Carbon won the $500,000 Wilkes Climate Launch Prize at the University of Utah. By the end of 2025, the plan calls for 20 to 25 units in the field.

Peer-reviewed science backs the play: biochar increases crop yields by approximately 16%, raises soil water-holding capacity by over 50%, and boosts nitrogen retention by 95%. Aramburu's target is larger still. "At scale, we can sequester billions of tons of CO2 annually in the form of biochar," he has said. The scientists agree: the theoretical ceiling is 2 billion tons per year, which would place biochar among the most consequential carbon removal pathways on earth.

Five generations of prototypes stand between the original idea and the current machine. The story of those five generations - of what broke, what burned, what needed rethinking - is the kind of details that Aramburu tends to skip over in interviews. He says simply: "We've been through five generations of prototypes and now we finally have something really scalable." That sentence is doing a lot of work.