# UNDO

Canonical page: https://technooptimist.io/companies/undo
London company that spreads crushed basalt and wollastonite on farmland in the UK and Canada so rain slowly turns CO2 into dissolved bicarbonate, and sells the carbon removal to buyers such as Microsoft.

## In brief

- 358,000 t of rock spread on 444 farms; 78,800 t of CO2 removal expected (company figures).
- Buyers include Microsoft (15,000 t deal, 2024) and Barclays (6,538 t, 2025).
- Uses basalt in the UK and Canadian wollastonite in Ontario.

## Facts

- Founded: 2022
- Headquarters: GB
- Status: private
- Website: https://un-do.com
- Frontiers: [Agriculture](https://technooptimist.io/agriculture.md) (Soil carbon & rock weathering)

## Programs

- [UNDO Enhanced Rock Weathering](https://technooptimist.io/agriculture/undo-rock-weathering.md) (Agriculture): Deploy. Rock spread on 444 farms across 61,000 acres in the UK and Canada; corporate offtakes growing.

## Technical approach

- **Rock: Basalt and wollastonite**: Crushed silicate rock, often a by-product of quarrying, is trucked to farms and spread like lime.
- **Measurement: Conservative, audited accounting**: Rock analysis, field data and soil and water measurements estimate removal; transport emissions are tracked and deducted.

## Open problems

- **Proving how much CO2 was removed** (active research): Weathering is slow and spread through soil and rivers, so removal must be inferred from samples and models.

## Latest updates

- **24 Sep 2025**: Barclays makes its first carbon removal purchase: 6,538 tonnes from UNDO's rock weathering in Ontario. Barclays agreed to buy 6,538 tonnes of permanent CO2 removal from UNDO, which will spread crushed silicate rock across 10,000 acres of farmland in Ontario, Canada. ([our story](https://technooptimist.io/stories/barclays-makes-its-first-carbon-removal-purchase-6-538-tonnes-from-undo-6150b96c.md) · [original source](https://www.esgdive.com/news/barclays-turns-to-enhanced-rock-weathering-for-first-carbon-removal-deal-undo/802500/))
- **26 Sep 2024**: Microsoft expands its deal with UNDO to remove 15,000 tonnes of CO2 by rock weathering in the UK and Canada. Microsoft signed a follow-on agreement with UNDO to permanently remove 15,000 tonnes of CO2, using crushed basalt on UK farmland and wollastonite in rural Canada. ([our story](https://technooptimist.io/stories/microsoft-expands-its-deal-with-undo-to-remove-15-000-tonnes-of-co2-by-4102619c.md) · [original source](https://bettersociety.net/Microsoft-partnership-aims-to-remove-15000-tonnes-of-CO2-from-the-atmosphere.php))

## Partners, customers and investors

- Microsoft (customer): 5,000 t removal deal (2023), then a 15,000 t follow-on (Sept 2024).
- Barclays (customer): Its first carbon removal purchase: 6,538 t via 10,000 acres in Ontario (Sept 2025).

---

The Techno Optimist tracks every frontier of technology, program by program: https://technooptimist.io/ (a Markdown version of any page: add .md to its URL; site map for agents: https://technooptimist.io/llms.txt).
Data API (JSON, realtime stream): https://technooptimist.io/developers. People read 5 pages free, then Reader $10/month; these Markdown pages are open to agents.