The world has a massive amount of carbon dioxide to remove to combat the worst effects of climate change, and rocks have the potential to make that job easier.
Naturally, rocks contribute to the carbon cycle through a chemical process called weathering. When carbon reacts with rain, it dissolves into the rock and is stored for hundreds or even thousands of years, with little risk that it will escape back into the atmosphere.
Scientists Philipp Swoboda, Niklas Kluger, and Elisabete Trindade Pedrosa think that by enhancing rock weathering, we can accelerate this process. Naturally, rock weathering is too slow to significantly mitigate human-caused climate change, but with enhanced weathering, the scientists can speed up the process by spreading finely ground silicate rock powders on agricultural lands.
The team is a part of the early-stage startup InPlanet and they’ve recently launched a project within the FootPrint Coalition Science Engine’s new Negative Emissions Technologies category. According to Swoboda, Kluger, and Pedrosa, enhanced weathering is not only “the most promising negative emissions technology” but it has the potential to improve both soil health and food security.
That’s why the team is focusing on the tropics, specifically the fourth largest producer of the world’s food: Brazil.
InPlanet works closely with farmers to enable lower-carbon agricultural practices and use natural rock powders from local mines instead of limestone, synthetic fertilizers, and pesticides. They sell Carbon Removal Credits for every tonne of carbon sequestered which InPlanet says can help companies to achieve their Net-Zero commitments.
As a result of the nutrient addition of fresh rock minerals, soils are regenerated which benefits crops, and InPlanet hopes to sequester one gigaton of CO2 “to create a livable planet with nutritious food and healthy ecosystems for future generations.”
For context, one gigaton of carbon is equal to a billion tonnes which according to the Environmental Protection Agency’s greenhouse gas calculator is the same as 790,053,853 gas cars driven for one year or 4,056,833,818,480 pounds of coal burned or 9,214 natural gas power plants used for a year.
InPlanet isn’t the only venture exploring enhanced weathering. While InPlanet is working in Brazil, San Francisco-based Vesta is accelerating ocean carbon capture through chemical weathering of olivine minerals.
Olivine is found naturally in certain coastal regions, however, like terrestrial rock weathering its small scale does not provide much benefit towards reducing atmospheric carbon. To improve the technology that captures CO2 more effectively, the climate change think tank, Climitigation, set up Project Vesta.
Like InPlanet, United Kingdom-based Undo is crushing rocks for the weathering process. Since piloting in Scotland, the startup says they are the first company to remove one million tonnes of CO2. One billion is its next target.
In Oman, the Prince William-funded startup 44.01, named after the molecular weight of carbon, is also turning to mineralization for carbon removal, but with the rock peridotite. By 2024 they aim to mineralize 1,000 tons of locally-captured CO2 and by 2040, they are also hoping to reach the billion mark.
According to Ulf Riebesell, a marine biologist at GEOMAR Helmholtz Center for Ocean Research in Kiel, Germany via National Geographic, rocks naturally sequester about a gigaton annually, but if scaled massively that one gigaton could multiply by 100. When humans emit about 36 gigatons of CO2 a year, the potential for enhanced rock weathering is eye-opening.
InPlanet’s goal of sequestering one gigaton while regenerating tropical soils is momentous, and with a Science Engine project, they can continue the research they need to accomplish the goal.
“We desperately need field experiments to outline the actual CO2 capture capabilities of these processes,” the scientists write.
Since launching in January, the research team has gathered in Brazil and is beginning baseline analysis and application of the rock powder this month. This field research is crucial to catalyzing enhanced rock weathering, but the project is only 51% funded and the team still needs bout $5,000 to reach their $10,000 goal.
But readers like you can help. At the time of this article’s publication, there are 15 days left to raise funding. Become a backer here and check out the Science Engine’s other new negative emissions projects.