Enhanced Rock Weathering: A Surprising Way to Cool the Planet

Harnessing Rock Weathering for Climate Change

• 💡 The process of rock weathering, where rainwater (weakened by CO2) erodes silicate rocks, naturally sequesters carbon dioxide.
• 🌍 This natural process, which turns dissolved CO2 into bicarbonate that eventually traps carbon on the seafloor, has historically balanced Earth's climate over millions of years.

Accelerating Carbon Sequestration

• 🎯 Enhanced rock weathering aims to speed up this natural process by using fast-weathering rocks like basalt.
• ⛏️ Key factors for accelerating weathering include using rocks with a suitable chemical composition (like volcanic rocks) and increasing the surface area exposed to the elements.
• 🌾 Crushed basalt can be spread on farmlands, leveraging existing agricultural knowledge and infrastructure.

Challenges and Potential of Enhanced Weathering

• ⚠️ Implementing enhanced rock weathering globally presents significant challenges, including the vast scale of mining, crushing, and distributing rock.
• 💧 The process is intertwined with the global water cycle, making its precise impact difficult to measure due to numerous variables.
• ⚡ Ensuring the energy used for quarrying and transport comes from clean sources is crucial to maintain a net carbon benefit.
• 🧪 Potential side effects, such as the release of heavy metals from quarried rocks, need careful consideration.
• 📈 Simulations suggest spreading 10 tons of basalt dust per hectare of farmland could sequester over 200 gigatons of CO2 in 75 years, highlighting its practical potential.