CO₂ removal through accelerated rain and wind

Enhanced Rock Weathering (ERW) offers a promising solution in the fight against climate change. It actively captures and stores carbon dioxide (CO₂) from the atmosphere by accelerating natural rock weathering processes. ERW uses crushed rocks or industrial byproducts rich in silicate minerals and strategically distributes them on the ground to trigger a reaction that forms stable carbonates.

The process of enhanced rock weathering

Continuous optimization and refinement of the subsequent process are key. These include selecting the most reactive rock types, finely grinding the material to increase surface area, and applying it under conditions that promote efficient carbon capture.

The first step in ERW is selecting the rock material. Typically, crushed rocks rich in silicate minerals, such as basalt, are well-suited for this type of carbon removal. Other options include quarry surplus and non-toxic industrial waste, which support circular economy principles. The size of the rocks matters, as rock crushed into powder has a larger surface area to react with rainwater.

The rock material is then spread on agricultural land, in forests, on abandoned coastal areas or other suitable areas using standard agricultural equipment.

When the rock powder comes into contact with rainwater, a chemical reaction occurs, similar to the way sugar dissolves in water, but it takes years or even decades. During this process, CO2 from the atmosphere dissolves in the rainwater, producing carbonic acid. The acid then reacts with the minerals, leading to the formation of carbonates and the stable storage of carbon.

Monitoring stations and research projects are being established to track the effectiveness of ERW and quantify the amount of CO2 captured (see below for further details).

Carbon credit certification is an option for ERW projects that enables the generation of carbon credits representing the amount of removed CO₂. These credits can be sold on the voluntary carbon market to help sustainability leaders offset unavoidable emissions.

Benefits of Enhanced Rock Weathering

ERW offers several advantages that make it a holistic method for mitigating climate change.

• Improved soil health: ERW materials, such as crushed basalt, release important nutrients such as magnesium, potassium, and calcium. This increases nutrient levels and promotes plant growth, which can ultimately lead to better yields.

• Fertilizer replacement: ERW applied to agricultural land improves overall soil health and reduces the need for expensive (chemical) fertilizers.

• Balancing ocean acidity: ERW helps combat ocean acidification by increasing ocean pH.

Challenges of Enhanced Rock Weathering

ERW faces challenges that need to be addressed to achieve effective carbon removal.

• Energy-intensive processes: Rock mining, crushing, transportation, and distribution can be energy-intensive. Sustainable procurement and the use of renewable energy are critical to ensuring a low carbon footprint. All emissions from production are offset before carbon credits can be issued, ensuring a true net-zero footprint for ERW project developers.

• Toxic heavy metals: Some rock types may contain toxic heavy metals, requiring careful selection and testing to avoid negative impacts on ecosystems and human health.

• Delayed effect of CO₂ removal: ERW is a gradual process that occurs over years and decades. While it provides permanent carbon storage, it may not solve urgent climate problems that require rapid carbon reduction.

Measurement, Reporting and Verification (MRV)

Accurate quantification of CO₂ sequestration is essential for the implementation and verification of ERW. Consider the following points:

• Total alkalinity (TA): Originally considered for quantification, TA may not be suitable for acidic soils with low pH values.

• Dissolved inorganic carbon (DIC): Accurate measurement of DIC is proving more effective for quantifying CO₂ sequestration. This approach uses specialized analytical instruments to quantify carbon dioxide, bicarbonate, and carbonate ions in solution.

• Field monitoring and research: Ongoing research and field monitoring efforts improve the accuracy of quantification and validate the effectiveness of ERW in different settings.

Conclusion

Enhanced rock weathering represents a promising and sustainable approach to combating climate change by actively capturing CO2 from the atmosphere. Despite the challenges, the benefits and potential for scalable carbon removal make ERW a valuable addition to climate mitigation efforts. Through ongoing collaboration, ERW can help companies complement their climate strategy and neutralize unavoidable emissions. Want to learn more or review our ERW projects ? Download our ERW flyer . Contact our team to schedule a free consultation.