How spreading crushed rock fights climate change and supports food systems

Just the gist

Short on time? Here’s what you need to know for this update:

• 🌎 Scaling enhanced rock weathering worldwide — Our project partner is currently active in the United Kingdom and Canada, with concluded pilot studies in the United States and Australia.
• 💥 Making an impact as a Wren community — Wren members have funded 25K+ tonnes of crushed silicate rock spread across thousands of hectares, which will remove 5K+ tonnes of CO₂.
• 👩‍🌾 Celebrating progress for the industry at large — New research, ongoing trials, and evolving industry standards show how enhanced rock weathering can support farmers while removing carbon from the atmosphere.
• 💡 Leading carbon removal conversations — Our project partner has participated in major climate events, including Climate Week NYC and London Climate Action Week, while also advancing as a finalist in the $100M XPRIZE Carbon Removal competition.

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Scaling enhanced rock weathering worldwide

Our Enhanced rock weathering project partner, UNDO, has spread 260K+ tonnes of crushed silicate rock across 16K+ hectares of agricultural land, since commencing operations in 2022. This will remove more than 52K tonnes of CO₂ from our atmosphere.

Our partner aims to remove one million tonnes of CO₂ per year by 2030, and they’re scaling quickly. They currently operate in the United Kingdom and Canada, with pilot studies completed in the United States and Australia.

Here's a breakdown of their achievements so far:

• England (active): 52,450 tonnes of rock spread across 2,580 hectares
• Scotland (active): 173,870 tonnes of rock spread across 8,420 hectares
• Canada (active): 25,560 tonnes of rock spread across 5,070 hectares
• United States (completed pilot): 14,580 tonnes of rock spread across 711 hectares
• Australia (completed pilot): 1,780 tonnes of rock spread across 64 hectares
• Total: 268,240 tonnes of rock spread across 16,845 hectares

The Wren community has directly funded about 10% of this impact—a remarkable achievement alongside major buyers like Microsoft. Specifically, Wren members have funded 25,821 tonnes of crushed silicate rock spread across 1,744 hectares, which will remove 5,724 tonnes of CO₂.

Our project partner is currently expanding the number of measurement sites across the United Kingdom and Canada as they investigate promising new quantification methods. These sites will collect and assess composite soil samples, and profile performance on various crop and soil types.

In Canada, UNDO has chosen Canadian Wollastonite to provide fast-weathering wollastonite—a mineral spread on agricultural land as a soil amendment that kick-starts the enhanced rock weathering process. When it rains, wollastonite releases calcium and bicarbonate ions. These react with water-based CO₂ to produce calcium carbonate, which securely stores carbon for thousands of years.

Celebrating progress for the industry at large

This year, our project partner shared promising results from their ongoing trial in partnership with Newcastle University. The study highlighted how basalt applied to spring oat crop boosted yields by 15% on average and was also effective at improving soil pH in temperate climates.

At Wren, we’re thrilled to see further evidence of how enhanced rock weathering can support farmers and improve food production, which holds so much promise for improving livelihoods in developing countries. UNDO is currently running agronomy trials in Tanzania and Kenya in partnership with the Sokoine University of Agriculture and has formed academic partnerships across six countries.

Another marker for industry progress has been an update to the enhanced rock weathering methodology from Puro.earth, the carbon removal crediting platform that sets the standards used by our project partner and makes carbon credits available for organizations like Wren to purchase.

This updated methodology increases the level of detail around monitoring and reporting, requirements for soil sampling, weathering material sampling, soil carbon monitoring, and quantifying uncertainty. At Wren, we support the continuous improvement of these methodologies to foster more rigor and transparency within the industry.

Leading carbon removal conversations

Over the past few months, our project partner welcomed the XPRIZE Carbon Removal judging panel to Scotland, showcasing their project operations. UNDO sits among the top 20 finalists for the award, with contestants required to demonstrate a working solution that removes at least 1,000 tonnes of CO₂ annually, with clear potential for gigatonne-scale impact.

The grand prize winner, to be announced on Earth Day 2025, will receive a staggering $50 million toward the project, and opens the door to additional model-based research and development aimed to help reduce the cost of carbon removal in the voluntary carbon market.

UNDO joined three fellow XPRIZE Carbon Removal finalists at Climate Week NYC to share insights on scaling carbon removal solutions. The panel focused on key success factors including securing project financing, upholding scientific standards, and building community support. UNDO is now preparing to showcase its gigatonne-scale carbon removal strategy in the XPRIZE competition’s final round.

Throughout the year, UNDO’s involvement at major climate events has shaped global conversations. At World Bank Group’s Innovate4Climate conference in Berlin, our project partner showcased proven carbon project results and standards alongside industry leaders. CEO Jim Mann brought valuable carbon removal insights to Carbon Forward North America’s expert panel in Toronto.

During London Climate Action Week, UNDO presented their vision for scalable, cost-effective carbon removal solutions to an elite community of innovators and investors at the Earthshot Prize Innovation Camp. Prince William was also in attendance, having been actively involved with the Earthshot Prize since launching the award program in 2020.

With growing support from international partners and increasing recognition in the carbon removal sector, our project partner aims to demonstrate the scalability of enhanced rock weathering technology across multiple sites.

We’re excited to continue helping our partners scale their operations and increase our collective impact. Your support is crucial in helping us expand our reach while tackling the climate crisis together.

That's all for this update! As always, thank you for your support.
— the Wren team 🧡