Could spreading rock dust across croplands remove carbon dioxide from the atmosphere?
Enhanced rock weathering could help offset carbon emissions from agriculture, contributing to reducing overall carbon dioxide levels in the atmosphere.
Natural weathering of rocks absorbs about 0.3% of carbon emissions. Researchers think that pulverizing silicate rocks, like basalt, and spreading their dust across farmland could absorb additional emissions while perhaps improving crop health and yields. Rain, which is slightly acidic, reacts with rock and soil to form bicarbonate that eventually washes into the ocean, where carbon would be locked away for thousands of years.
The technology is in its early phases of testing. Research shows the process can work at a large scale--farmers already sometimes mix crushed limestone into soil to offset acidification from fertilizers. But the cost-effectiveness in various climates remains unknown.