Interventions
We are looking at two interventions that have been proposed to help mitigate climate change by removing carbon from the atmosphere and converting into inorganic carbon in soil and water. Our models aim to understand the effects of enhanced rock weathering and ocean alkalinity enhancement.
Enhanced Rock Weathering
Rock weathering is a natural process that controls the earth’s climate on geologic timescales. Rocks react with carbonic acid in rain water and dissolve, pulling carbon dioxide out of the atmosphere and converting it into bicarbonate in soil pore water (the water in between soil particles). That carbon rich rain water then percolates through the soil profile and is deposited in rivers, lakes, and the deep ocean. Weathering of silicate rocks like basalt is particularly effective at removing carbon dioxide, a greenhouse gas, from the atmosphere.
Enhanced weathering involves pulverizing silicate rocks into dust and spreading it on soils with the aim of accelerating the rate of weathering and subsequent carbon dioxide removal from the atmosphere.
Ocean Alkalinity Enhancement
Ocean alkalinity enhancement is an approach to carbon removal that involves adding alkaline substances to seawater to accelerate the ocean’s natural carbon sink. Adding alkalinity to the ocean converts dissolved inorganic CO2 in seawater into bicarbonates and carbonates, which are stable forms of carbon with a lifetime of approximately 10,000 years. The resulting CO2 deficit in surface waters is quickly rebalanced via a net movement of atmospheric CO2 into the ocean, to reestablish equilibrium.