The natural rock weathering process, while effective in breaking down carbon and storing it within rocks over thousands of years, may not provide the immediate solution to combat climate change. With the urgency of the situation, waiting millions of years might not be feasible as our planet continues to accumulate greenhouse gases without significant mitigation efforts.
One potential solution is “enhanced rock weathering” which aims to accelerate the natural process. This technique involves grinding a substantial quantity of rocks into fine powder to maximize their surface area, which is then spread over the ground. By increasing the rate of weathering, the enhanced process holds the potential to capture and store carbon more rapidly.
According to a BBC report, scientists affiliated with the United Nations have warned that simply reducing greenhouse gas emissions will not suffice to prevent perilous levels of global warming. They emphasised the need to actively remove carbon dioxide from the atmosphere.
How does ‘enhanced rock weathering’ help remove CO2?
Over millions of years, carbon dioxide in the atmosphere has been combining with rainwater, forming carbonic acid. This natural process occurs when the acid falls on mountains, forests, and grasslands. As a result, the carbon dioxide interacts with rocks and soil, undergoing mineralisation and secure storage in the form of carbonate.
Enhanced rock weathering takes advantage of this phenomenon by utilizing finely crushed rock particles. This increases the contact area between rainwater and rock, consequently enhancing the weathering process and facilitating greater carbon removal.
UNDO, a pioneering company, aims to expedite the process of rock weathering by applying crushed basalt rock onto farmland.
The company focuses on reducing the timescale required for the process, condensing it from millions of years to mere decades. Once the reaction between carbon dioxide and the weathered rock takes place, the resulting greenhouse gas is sequestered and securely stored for thousands of years.
How does the process help crop and soil?
Enhanced weathering, achieved through the application of nutrient-rich rocks to soil, offers multiple benefits. It not only facilitates carbon dioxide storage but also improves crop yields by providing essential nutrients like phosphorus and potassium.
Furthermore, it enhances soil fertility, nutrient availability, and reduces the dependence on fertilizers. The process also aids in ocean restoration by reducing ocean acidification through the release of bicarbonate ions. Additionally, weathering products increase soil water retention, assisting plants during drought conditions.