Glossary
Enhanced weathering
Enhanced weathering is a geoengineering approach designed to accelerate the natural process of the Earth's weathering to counteract the accumulation of carbon dioxide (CO2) in the atmosphere, a primary contributor to global warming. This technique seeks to mitigate the impact of climate change by using silicate rocks, such as basalt or olivine, to absorb CO2 and reduce greenhouse gases in the atmosphere.
Under natural weathering, the process begins when rainwater, which absorbs CO2 from the atmosphere creating a mild carbonic acid, reacts with silicate rocks. This chemical interaction leads to the formation of bicarbonates, which are carried to the ocean and are used by marine organisms to make their shells out of calcium carbonate. Following the death of these organisms, these carbonates are deposited at the ocean floor, effectively sequestering the carbon for millions of years.
The process of enhanced weathering primarily revolves around the widespread distribution of pulverized silicate rocks, like olivine, over agricultural lands. The tiny rock particles expedite the soil’s inherent capacity to capture and store CO2, and the reaction simultaneously releases nutrients, such as magnesium and iron, which improve soil quality. This method, therefore, has the dual potential of drawing down CO2 from the atmosphere while also enhancing soil fertility.
Additionally, enhanced weathering also has the potential to improve ocean alkalinity, which can bolster marine ecosystems’ carbon sequestration capacities. As the bicarbonates from weathered rocks flow into the ocean, the elevated alkalinity can help counteract ocean acidification (a destructive condition caused by excessive absorption of CO2) and protect marine life.
However, enhanced weathering is not without its challenges. The process is somewhat slow, requires vast quantities of rock, and has substantial energy and cost demands. Despite these hurdles, with ongoing advancements in technological interventions and strategic planning, enhanced weathering has the potential to be a part of a multifaceted approach to managing global atmospheric carbon levels.