This is a pile of 29 tons of basalt - enough to pull 9 tons of CO₂ from the atmosphere

What you see here is a pile of 29 tons of basalt dust, one truckload. Over the next few years this basalt will suck 9 tons of CO₂ from the ambient air when the dust is simply spread on half a hectare or one hectare of cropland. With this pile an average citizen of Germany is becoming climate neutral for one year.

If we successfully reduce emissions by 90% in 20-30 years only one tenth of this pile would be necessary for each citizen every year. Even if we may be unable to do this for all 83 million Germans in 2050, we are convinced that basalt will be one of the working solutions for the climate crisis.

This process is called “enhanced weathering”. It is a completely natural process that has been pulling CO₂ from the atmosphere for millions of years. CO₂ from the air combines with rainwater to form a weak acid which reacts with the basalt. Harmless carbonates are created in the process and the CO₂ is bound for thousands of years. Plus: The basalt releases nutrients for the plants and improves the soil.

The fact that this process of CO₂ sequestration actually works as been shown by hundreds of studies. Basalt is allowed as soil amendment e.g. in the EU. The amount of 0,3 tons of CO₂ per 1 ton of basalt is based on simple chemistry/stoichiometry. The only remaining question that scientists all over the world are currently working on is: How many years does it take until the basalt has been weathered and pulled down the CO₂? In the lab we can successfully show that 1-2% of the potential are happening in pure soil (=without much biology). In open nature, with plants, roots, flora, fauna, fungi and active decay we expect at least 10x of this speed - in part because there is so much more CO₂ in the soil than in thin air. Some scientists think it can happen in as little as 4 years (depending on soil, rain, etc.).

At Project Carbdown we are working on the measurements for enhanced weathering. Stay tuned!

But you can start with this now already! If you want to do good for the climate and if you own a piece of land, large or small: Go, and spread some basalt dust!

PS: There are several co-benefits from spreading basalt on croplands, we’ll post a blog article about this later.