21. UNDO: the startup targeting one billion tonnes of CO₂ removal Forget trees, UNDO is using rocks to suck up CO2, taking a faster, science-backed, approach to climate action. About the Startups 100 Now in its 17th year, the Startups 100 is the definitive list of the most promising new UK businesses. There's no fee for entry or for inclusion in our index. The Startups team of new business experts judge all our top 100 entrants in collaboration with specialist industry consultants. See our guide to this year’s hottest new businesses and most exceptional founders in the complete 2025 Startups 100 index. Founder: Jim MannYear founded: 2022Website: un-do.comVarious greenwashing scandals have made today’s consumers more wary of carbon offsetting. Projects can be low-quality. Many don’t go further than planting trees, a method which could take centuries to provide actual environmental impact.One provider that is going further is UNDO. Also in last year’s Index, the firm has emerged as one of the most credible Carbon Dioxide Removal (CDR) providers. Spotting that many CDRs are — for all intents and purposes — barking up the wrong tree, founder Jim Mann instead threw his weight behind Enhanced Rock Weathering (ERW).ERW works by crushing silicate rock and spreading it on soil. The rock naturally begins to weather, removing atmospheric CO2 while also enriching the soil with essential nutrients.With few competitors in the space, UNDO has largely been creating its own playbook. Its biggest challenge was educating the market on a little-known, science-backed product. To do so, Mann has leaned heavily into the data. That included building out UNDO’s unique data platform, NEWTON, which collects real-time data on every step of the process. And, because ERW begins removing CO2 straight away, that data starts almost instantly.Beyond vague promises of ‘green spaces’, this allows customers to see the impact of their investment down to a single tonne of CO2. Unlike tree planting, CO2 is also permanently locked away for thousands of years. Once the carbon is removed, it cannot be reversed.UNDO’s mission is long-term, but it hit some key milestones in 2024. Microsoft renewed its contract, which will see UNDO spread 60,000 tonnes of silicate rock across the UK and Canada. The tech giant also agreed to fund the startups’ Measurement, Reporting, and Verification (MRV) enhancement trials, to further develop NEWTON.UNDO’s short-term aim is to capture more than one million tons of atmospheric CO2. But it also wants to work with other nature-based CDR suppliers to strengthen the industry’s reputation. In 2023, it was one of the founding signatories of the Reykjavik Protocol, a set of principles that governs how suppliers should responsibly bring their solutions to markets. “At UNDO, we see carbon removal as a team sport”, says Mann. That may be true. But In the race against time for high quality CDR projects, UNDO is certainly the team leader. The 2025 Startups 100 List in Full 1 Lottie 2 Robin AI 3 Yonder 4 HIVED 5 Gaia 6 Runna 7 Quantum Dice 8 Hoxton Farms 9 MAGIC AI 10 Eolas Medical 11 DRIFT Energy 12 Audiomob 13 Lindus Health 14 FYLD 15 Zero Gravity 16 Vikela 17 ToffeeX 18 Bio&Me 19 Strolll 20 Triple Technologies 21 UNDO Carbon 22 KOMI 23 Untap 24 Novai 25 Omni Pet 26 Sona 27 Fin Sustainable Logistics 28 trumpet 29 Swiipr Technologies 30 Cerbos 31 By Rotation 32 Open Climate Fix 33 Howbout 34 cheqd 35 Seep 36 Oort Energy 37 Walking on Earth 38 Flexa 39 HutanBio 40 Primer 41 Black Seed Ventures 42 Sharesy 43 Made With Intent 44 Userled 45 Zeti 46 Luna Daily 47 Deploy Tech 48 PulpaTronics 49 Metris Energy 50 VoltShare 51 NOQ Group 52 Hormona 53 Unify AI 54 The Seam 55 Siloton 56 SURREAL 57 Valarian Technologies 58 Papaya Technologies 59 PEEQUAL 60 PlantSea 61 Bloom Money 62 Tonic Health 63 Stored. 64 Cult Mia 65 Atlantic Money 66 facia.ai 67 RideTandem 68 Monk 69 STOCKED 70 IMPOSSIBREW 71 Mindgard 72 Grub Club Pets 73 Financielle 74 Outverse 75 Automated Architecture 76 Freja 77 Purple Transform 78 Lumi 79 Storekit 80 Unfabled 81 Asan Wellness 82 Mach42 83 seedata.io 84 Peachies 85 Nugget Savings 86 Enbiosis Biotechnology 87 Swoperz 88 growze 89 ekko 90 Tunic Pay 91 SKIN 92 Cashblack 93 TaskHer 94 XR Therapeutics 95 Alyve 96 UJJI AI 97 Volunteero 98 SuperFi 99 PharmAppy 100 Cogs AI See more Share this post facebook twitter linkedin Tags 2025