The concept of Enhanced Weathering Carbon Removal is gaining momentum as a potentially significant method for removing billions of tonnes of CO₂ from the atmosphere, thus aiding global efforts to achieve net zero emissions and mitigate the most dangerous effects of climate change. This method involves spreading crushed silicate rocks, such as volcanic basalt, across open fields, notably on farmlands, where they also benefit crop growth.
In this process, CO₂ dissolved in water reacts with calcium and magnesium in these rocks to form bicarbonate minerals, effectively storing carbon. Over time, these minerals are transported to oceans, locking away the carbon for millennia. This artificial acceleration of the natural rock weathering process, which typically occurs over geological timescales, aims to increase the reaction rate by enhancing the rock’s surface area exposure to CO₂.
The article in ‘Fix the Planet’ examines various ongoing enhanced weathering carbon removal projects worldwide, highlighting their growth from theoretical concepts to large-scale implementations. Companies across every continent except Antarctica are now initiating projects, spreading hundreds of thousands of tonnes of rock dust over extensive farmland areas. For instance, InPlanet in Germany has launched a significant project in South America, while UNDO in the UK is expanding its operations across several countries, exploring different types of weathering rocks.
However, a crucial challenge for enhanced weathering carbon removal is accurately measuring the actual amount of CO₂ captured and stored. This measurement is vital for generating reliable carbon credits, an essential aspect for these projects’ financial viability and environmental credibility. The complexity of measuring lies in the various factors influencing the weathering process, such as rock type, particle size, soil acidity, and climatic conditions.
Despite these challenges, proponents of enhanced weathering carbon removal emphasize its potential dual benefits. Apart from CO₂ removal, this method can improve soil quality, making it less acidic and more conducive for crop growth, thus providing an attractive proposition for farmers. For instance, trials in the UK showed a significant increase in crop yields following basalt rock treatments.
As the world grapples with the urgent need to reduce atmospheric CO₂ levels, enhanced weathering emerges as a promising technique. However, its scalability and effectiveness are contingent upon overcoming obstacles like precise CO₂ measurement and establishing standardized monitoring protocols. The ongoing research and pilot projects worldwide are crucial steps towards refining this method and realizing its potential in the fight against climate change.