carbon-sequestration
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Sustaera Scrapped Years of Work to Build a Cheaper Carbon-Capture Machine
Direct air capture has a brutal math problem: too much machinery chasing too little CO2. The North Carolina startup’s answer was to kill its first product, shrink the team and redesign the machine around electricity, ceramics and a cost target the market might actually buy.
Revalue
Revalue (Revalue Nature) is a London-based climate-tech company that develops high-integrity, nature-based carbon credits and builds the analytics platform behind them. Combining forest science, AI, remote sensing (satellite, drone and LiDAR), dynamic baselines and biodiversity monitoring, it partners with on-the-ground project operators and capital providers to design credits that avoid, remove and durably store CO2. Founded in 2022 and led by CEO Stuart Rowland, the company raised a $10M Series A in 2023 co-led by Ecosystem Integrity Fund and SJF Ventures.
Flash Forest
Flash Forest is a Toronto-based reforestation company that uses drones, proprietary biological seed pods, aerial mapping, and machine learning to replant forests faster and cheaper than traditional hand-planting. Founded in 2019, it deploys aerial and ground-based systems to restore land degraded by wildfire and logging, and pairs planting with a forestry intelligence service that surveys and monitors forests. The company has planted more than 3 million trees and aims to reach one billion by 2028.
Loam Bio
Loam Bio is an Australian agricultural biotechnology company using naturally occurring microbial fungi to help crops store more stable, long-lasting carbon in soil. Founded in 2019 by a group of farmers and climate scientists, it coats seeds with its CarbonBuilder inoculum so plants pull atmospheric CO2 into recalcitrant, mineral-bound soil carbon, and pairs the biology with its SecondCrop program that helps growers measure, verify and sell soil carbon credits. Backed by more than US$119M from investors including Lowercarbon Capital, Wollemi Capital and Marc Benioff's Time Ventures, Loam is scaling from its Orange, NSW base into the United States.
Carba
Carba is a Minneapolis-area climate-tech company that turns low-value waste biomass - dead trees, yard waste, and other biogenic scraps - into a stable, charcoal-like material called biocarbon (biochar). Using a patent-pending autothermal pyrolysis reactor and an anoxic (oxygen-starved) burial method, Carba locks carbon away for a certified 1,000+ years, most notably inside existing landfills where the material can also filter pollutants. The company sells the resulting permanent carbon-removal credits - including a five-year, 44,000-tonne deal with Microsoft - and aims to remove a billion tons of CO2 by 2035.
Terraton
Terraton is a San Francisco climate-tech company that turns agricultural waste into biochar - a stable, carbon-rich material that locks away CO2 for centuries. It packages financing, hardware, and software into a 'biochar business in a box' so agribusinesses in emerging markets can launch carbon-removal facilities, while corporate buyers get verified, high-durability carbon credits delivered at scale. Backed by an $11.5M seed round co-led by Lowercarbon Capital and Gigascale Capital, Terraton already runs facilities in Ghana and Kenya.
Applied Carbon
Applied Carbon (formerly Climate Robotics) builds tractor-pulled machines that turn crop residue into biochar in a single pass across the field. The Houston-based startup converts post-harvest plant waste into a stable form of carbon that improves soil health and locks CO2 underground for centuries, selling carbon removal credits to buyers including Microsoft.
Terranova
Terranova is a Berkeley-born climate-tech and robotics startup building car-sized autonomous robots that inject a wood-waste slurry deep underground to lift flood-prone land out of harm's way - no seawalls, no surface disruption. A single 'mothership' coordinating three injection rovers can raise about one acre by one foot per day, while the buried biomass becomes a durable carbon sink that can be sold as carbon credits. Founded by UC Berkeley mechanical engineer Laurence Allen to save his hometown of San Rafael, California, the company raised a $7M seed round in November 2025 and plans its first San Rafael pilots in 2026.
BioSqueeze Inc.
BioSqueeze Inc. is a Butte, Montana company and the self-described world leader in commercial biomineralization. Its core technology pumps low-viscosity, self-diverting fluids carrying naturally occurring soil bacteria into oil and gas wells, where the microbes precipitate crystalline calcium carbonate (limestone) to permanently seal leakage pathways as small as one micron. The result is a gas-tight barrier that eliminates sustained casing pressure and stops fugitive methane emissions, helping operators meet well-integrity and environmental obligations across producing, plugged, and storage wells.
Varaha
Varaha is an India-based climate-tech company that builds high-integrity carbon removal projects in the Global South. Working with roughly 170,000 smallholder farmers across about 1.7 million acres, it generates verified carbon credits through four pathways - regenerative agriculture, agroforestry, biochar, and enhanced rock weathering - and quantifies the results with a measurement, reporting and verification (MRV) platform powered by remote sensing, machine learning and field science. Its credits are bought by buyers like Google, Microsoft, Lufthansa and Swiss Re.
Vaulted Deep
Vaulted Deep is a Houston-based climate tech company that turns sludgy organic waste - biosolids, manure, food and agricultural waste, paper sludge - into permanent carbon removal by injecting it thousands of feet underground using patented slurry sequestration technology. Spun out of injection-well specialist Advantek in 2023, the company offers durable, low-cost, gigaton-scalable carbon dioxide removal while diverting hard-to-handle waste from landfills, oceans and fields. Its credits have been bought by Microsoft, Frontier Climate and others, and it won $8M in the Musk-backed XPRIZE Carbon Removal competition.
Andes
Andes is a climate-tech and agricultural biotechnology company using beneficial soil microbes - applied as a seed coating on corn, soybean, canola and wheat - to convert atmospheric CO2 into stable soil inorganic carbon. Founded in 2016 by Gonzalo Fuenzalida and Tania Timmermann and headquartered in Alameda, California, Andes pairs microbial biology with field-scale measurement to deliver permanent, low-cost carbon removal across millions of acres of working farmland.
Heirloom Carbon
Heirloom Carbon Technologies is a San Francisco-based direct air capture company that uses limestone's natural CO2-absorbing properties to pull carbon dioxide permanently out of the atmosphere. Their process accelerates a geological phenomenon that normally takes thousands of years into a 3-day cycle: calcium oxide powder absorbs CO2 from ambient air, becomes limestone, gets heated in a renewable-energy-powered electric kiln to release the captured CO2, and repeats. The captured CO2 is then stored permanently underground or embedded in concrete. Founded in 2020, Heirloom opened America's first commercial DAC facility in Tracy, California in November 2023 and has raised over $354 million to expand capacity toward their goal of removing 1 billion tons of CO2 by 2035.
Charm Industrial
Charm Industrial is a San Francisco-based climate company that converts agricultural residues into bio-oil through fast pyrolysis and injects it deep underground for permanent carbon removal. Founded in 2018 by Peter Reinhardt, Kevin Meissner, Shaun Meehan and Kelly Hering, Charm is one of the fastest-growing carbon dioxide removal companies and counts Frontier, Stripe, Microsoft, JPMorgan Chase, Meta and Shopify as customers.