Basalt Band-Aid: The Quixotic Quest for Carbon Capture

The Absurdity of Enhanced Weathering for Climate Change Reduction

Climate change is claimed to be driven by increasing concentrations of atmospheric CO2 and poses a significant challenge of our time. In response, various carbon capture strategies have been proposed, including the enhanced weathering of basalt.

Source: https://frontierclimate.com/writing/lithos

Basalt, a fine-grained volcanic rock, is a common feature on Earth's surface. It is found on the ocean floor, on volcanic islands, and all of the continents. Basalt is rich in elements such as calcium and magnesium, which can react with CO2 to form carbonate minerals, effectively trapping the carbon. This process, known as carbon mineralization, has been hailed as a potential solution to Earth's climate woes.

However, the irony of this situation lies in the fact that Earth has already done a fantastic job of covering its surface in basalt. From the vast expanses of the ocean floor to the volcanic islands scattered across the globe, Earth's surface is already a basalt wonderland.

Enhanced weathering of basalt (EWB) is a proposed carbon capture and storage (CCS) technique that aims to accelerate the natural process of mineral weathering to remove atmospheric CO2. Here I explore the absurdity of relying on accelerated basalt weathering as a major solution for CO2 reduction, considering Earth's extensive basalt coverage and the complexities and costs of the method.

In natural settings, when basalt is exposed to atmospheric conditions, it undergoes chemical weathering. This process involves the reaction of the rock with CO2 and water, resulting in the formation of carbonate minerals and the release of metal ions. These minerals are stable and effectively lock away the CO2 in a solid form.

To enhance this natural weathering process for EWB, basalt needs to be ground into fine particles. This increases the surface area of the rock, making it more reactive with CO2. The ground basalt is then distributed over large areas of land, such as agricultural fields. This distribution is a significant logistical challenge, requiring substantial energy and resources.