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Product, Service & Design Innovation
Startup on a Mission to UNDO Climate Change by ‘Putting Carbon in Its Place’

Using enhanced rock weathering to draw down carbon from the atmosphere, UNDO aims to spread enough crushed rock on farmlands by 2025 to permanently remove 1M tons of CO2.

Every year, humanity releases an alarming 40 billion tonnes of carbon emissions into the atmosphere — driving global temperature increases. This mounting crisis is exemplified by the long-term average temperature, which has already soared to 1.2°C above pre-industrial levels, with a perilous 1.5°C milestone looming on the horizon. In 2021, atmospheric carbon levels surged to a concerning 415 parts per million — marking a staggering 20 percent increase in just 42 years and pushing us ever closer to global tipping points.

The urgency for action is palpable, accentuated by the scientific consensus demanding the removal of 10 billion tons of carbon per year by 2050 to curtail the most devastating impacts of climate change. To restore our planet's delicate equilibrium, we need innovative solutions that actively remove carbon from the atmosphere. This is where companies such as UNDO come into play.


Founded in 2022, UK-based UNDO is already a leader in the exploding carbon-removal market — in this case, demonstrating the potential of enhanced rock weathering (ERW) to undo the climate-changing impacts of carbon dioxide.

“At UNDO, our ultimate goal is to reach gigaton-removal scale by spreading CO2-capturing rock on agricultural land around the world,” Nick Acfield, Account Manager at UNDO, explains to Sustainable Brands®. “When we talk to companies, the initial focus has to be on their decarbonization and switching away from fossil fuels — we stress that even as a carbon-removal organization. But this reduction is not enough; we are going to have to remove carbon from the atmosphere.”

ERW is situated at the intersection of nature-based and engineered carbon-removal solutions. The former includes techniques such as tree planting — a quintessential, natural method of carbon capture. While economical, these solutions have their limitations — being that trees only sequester CO2 for their lifespan and don’t capture their full potential for many years. They release their stored CO2 during decomposition or burning, often caused by logging and clearcutting for farmland.

On the other end of the spectrum, direct air capture (DAC) offers an effective and metered, though costly, means of mechanically extracting CO2 from the atmosphere and securely sequestering it underground. However, DAC can be energy-intensive — so, until we successfully shift our global power mix to renewables, energy-heavy technologies are counterproductive in terms of reducing reliance on climate-changing fossil fuels.

Approaches such as ERW offer a compelling compromise. This technique accelerates the speed and efficiency of the natural process of rock weathering, which gradually absorbs carbon over geological timescales. In doing so, it provides an avenue for sustainable and relatively rapid carbon removal — presenting an attractive solution to mitigate the impacts of climate change. By focusing on enhancing the carbon-sequestration ability of agricultural lands, UNDO is building on the work of fellow ERW innovators such as Vesta — which is applying the technique to coastal systems.

“People know that plants and trees absorb CO2; but most of the carbon on Earth is stored in rocks or sediments or as bicarbonate — far more than is in organic matter like plants or trees,” Acfield explains. “And rock weathering is one of the most natural ways of regulating the amount of CO2 that's in the atmosphere.”

The process

Enhanced rock weathering is a process where CO2 in the air is absorbed by raindrops, forming weak carbonic acid (H2CO3). When this rain falls on silicate or mafic rocks, the carbonic acid reacts with the minerals — converting CO2 into stable bicarbonate ions. These ions eventually find their way through soils and groundwater into the ocean, where they help to deacidify our oceans and remain for long geological periods — roughly 100,000 years.

This process is a long-lasting and effective way to remove CO2 from the atmosphere, in contrast to plants that take up carbon temporarily and release it when they die. In fact, weathering already naturally removes approximately 1 billion tons of CO2 from the atmosphere each year.

UNDO sources its crushed silicate rock, primarily volcanic rocks such as basalt, from quarries. Commonly used in construction and road-building, powdered basalt rock is left behind in large quantities. UNDO acquires this material from quarry stockpiles and applies it to farmlands for practical use.

“When this rock is spread on farmland, it breaks down — releasing important plant nutrients in the process. This enriches the soil, improves its pH levels and increases crop yields for farmers,” Acfield says. “And of course, because the reactive surface area of the rock is much greater, the CO2 capture process is exponentially faster.”

These vital nutrients (namely phosphorus, potassium, magnesium and calcium) act as natural fertilizers and prevent the need for other expensive soil inputs such as liming. Along with sequestering carbon, ERW supports farmers, creates local employment opportunities, and benefits biodiversity — furthering several UN Sustainable Development Goals.

Along with these impressive co-benefits, UNDO's solution offers permanence — as it locks away carbon for thousands of years; versus carbon stored in soil — which can be easily released again during tilling of farmland, extreme weather or other disturbances. It is scalable due to the abundant supply of silicate rocks such as basalt, which is the most common rock on Earth. It is also highly sustainable, as UNDO uses existing infrastructure and machinery to carry out its operations — which the company claims boast a > 90 percent carbon efficiency; and it continually strives to optimize to remove more carbon with fewer emissions.

Over the past 18 months, UNDO has reached more than 70 employees and has spread 150,000 tons of rock — which is expected to sequester 35,000 tons of CO2 over time. The sequestration process typically takes around 20 years for basalt rock, with the majority occurring in the first 7 to 10 years. UNDO is researching other rock types that, though not as abundant, have shorter weathering timelines to capture more CO2 faster.

Working with local communities

UNDO sources its rock from quarries in Scotland, Northern England, Canada and Australia — creating another revenue stream for local suppliers. The company takes pride in trying to keep benefits within the communities it operates: In addition to purchasing crushed rock from local quarries, it spreads it within 20 miles of where it was sourced — only hauling the rock further when absolutely necessary — and employs local contractors throughout the carbon-removal process. The company gives farmers the rock for free, which reduces their expenditure on fertilizers while simultaneously enhancing their crop output.

Importantly, UNDO regularly tests its rock for potentially toxic elements such as heavy metals or materials that could damage the soil or seep into water sources.

“We've now got too much demand from farmers in the UK, which is a really good place to be. Farmers are getting FOMO in the communities; because if a neighborhood farm is doing something new, it always sparks competitive interest,” Acfield explains. “And there's been quite a lot of evidence from farmers concerning the benefits to their land and crop — being able to harvest more hay, for example.”

UNDO is currently scoping regions of interest to further franchise and scale. It has developed a proprietary, global screener which overlays silicate rock feedstocks, quarry operations, farmland availability and more to assess potential next areas of expansion.

The carbon market

UNDO's business model relies upon corporate buyers who wish to meet their net-zero goals through buying carbon removal. The company’s unique appeal lies in its capacity to address the quality and effectiveness concerns inherent in the voluntary carbon market. Quality assurance is crucial due to the market's perceived opacity and reputational issues. UNDO’s carbon credits stand out — as they have multiple co-benefits and are much more price-competitive than other high-permanence solutions.

Transparency and accountability in carbon removal are key priorities for UNDO. Its comprehensive measurement, reporting and verification (MRV) system, supported by a world-class science team, ensures that companies buying carbon credits can confidently claim their legitimacy. MRV forms the foundation of the business, helping to prevent greenwashing and establishing scientific credibility in the carbon-removal process.

UNDO collaborates with a diverse range of companies seeking reliable carbon-removal solutions to fulfill their carbon removal targets. The company exclusively partners with companies firmly dedicated to reducing their emissions first and using carbon removal to reach net zero. Earlier this year, UNDO became Microsoft's first ERW supplier, announced a $12 million funding round led by Lowercarbon Capital, and announced a $1 million contract renewal from Stripe — one of the world’s leading carbon-removal purchasers. And just last week, it announced a landmark collaboration with British Airways, CUR8 and Standard Chartered in a first-of-its-kind pilot for financing carbon removal.

"This is a really exciting time for UNDO. We are seeing a lot of interest from many corporations, and we are partnering with scientific bodies and academic institutions around the world,” Acfield says. “It's heartening to witness the world's collective determination to combat climate change and embrace innovative solutions. Together, we're forging a path toward a more sustainable and hopeful future.”