The use of Enhanced Rock Weathering (ERW) to combat climate change by capturing carbon dioxide through accelerated weathering of rocks is promising.
Enhanced Rock Weathering (ERW)
ERW is a technique aiming to speed up the natural geological process called weathering, where rocks breakdown through carbonic acid, capturing carbon dioxide as bicarbonate and eventually forming limestone. This method is increasingly being adopted globally, including in India and Brazil, to combat climate change.
Mechanism
- Involves the use of quick-weathering rocks like basalt, finely ground to increase surface area.
- Natural process accelerated to capture more CO2 efficiently.
Effectiveness and Challenges
- Potentially significant carbon capture but varies based on factors like rock type, climate, and soil.
- Measurement difficulties, with current methods focusing on cations released during weathering.
- Risk of overestimating captured carbon leading to inaccurate carbon credits.
Benefits and Risks
- Increased soil alkalinity can improve crop growth and soil health.
- Potential environmental benefits by neutralizing acids that would otherwise cause CO2 release.
- Risks include potential heavy metal contamination and incorrect measurement of carbon capture.
Global Adoption and Projects
- Projects in Europe, North and Latin America, Asia, including tea plantations in India's Darjeeling.
- Significant deals, such as Google’s order for 200,000 tonnes of carbon removal credits from start-up Terradot.
- Success stories like Mati Carbon winning the $50 million X Prize for carbon removal projects in India.
The text underscores that while ERW is considered safe, careful calibration and more research are essential for accurate carbon capture measurement and maximizing its potential environmental benefits.