Two-Fold Effect

20 October 2021, by Ute Kreis

Photo: Artwork: Rita Erven, GEOMAR

Prof. Hartmann, the weathering of rocks can help to remove CO₂ from the atmosphere. How does it work?

In order to achieve the Paris climate goals, we need to actively remove carbon dioxide from the atmosphere. Through afforestation, fixation in biochar, or by storing greenhouse gas underground – or by accelerating the natural weathering of rocks. This process consumes CO₂, which is removed from the surrounding air.

You believe the method also has other advantages?

Ground basalt rock, which we spread on crop fields, also serves as a fertilizer. The soil becomes more fertile, and more biomass can grow. In turn, more carbon can potentially be stored. This means that the potential for removing CO₂ from the atmosphere using basalt is far greater than previously thought.

Could the process be easily implemented?

There’s plenty of suitable rock available, the technology is tried and tested, and it could be rapidly scaled up. To do so, we would need to intensify basalt mining, wherever possible in remote areas and ideally using renewable energy sources. This could be a viable option in the future. Before then, however, we need more data and field experiments to rule out any unwanted side effects.