Rock dust could be farming’s next climate solution

From Smithsonian magazine SmartNews

For farming, the latest climate fix isn’t especially high tech or glossy. By spreading rock dust over large swatches of land, carbon dioxide could be trapped in transformed, scrubbing it from the atmosphere. If this technique, called enhanced weathering, were to be employed around the world, scientists estimate two billion tons of carbon dioxide could be removed from the atmosphere each year.

In a paper published in the journal Nature July 8, researchers at the University of Sheffield laid out the potential costs and impact of the process. If the three countries that emit the most carbon dioxide —China, the United States and India—adopted the practice, one billion metric tons could be scrubbed from the air.

Enhanced weathering essentially speeds up natural processes of erosion and chemical reactions using newly introduced minerals. During the process, rocks are crushed and transported to farmland, where they are spread over a large area once a year, reports Lyndsey Layton at the Washington Post. When it rains, water dissolves silicate or carbonate materials in the dust. This cycle causes carbon dioxide to be pulled from the atmosphere into the solution, forming bicarbonate ions. Over time, these ions are washed into the ocean and form carbonate minerals, trapping the carbon for at least 100,000 years.

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