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Enhanced Rock Weathering 101: Your Essential Carbon Removal Guide

Enhanced Rock Weathering 101: Your Essential Carbon Removal Guide

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May 7, 2024

Enhanced rock weathering (ERW) is an innovative solution that harnesses the power of nature to remove carbon dioxide from the atmosphere. Rather than reinventing the wheel, ERW accelerates the planet’s natural mineralization cycle by crushing rocks and transporting them to the right environment, allowing them to weather at an accelerated pace.

ERW is a scalable carbon removal (CDR) pathway rooted in geochemistry that’s been going on for millions of years. In nature, rock weathering is a process that has been optimized over millennia, helping to balance our planet’s carbon cycles: As rocks are exposed to rain and acidity, they slowly erode, releasing calcium and magnesium. At the same time, CO2 from the air undergoes its own reactions to become bicarbonate. These compounds meet within soil water, combine into calcium carbonate, and get transported through waterways and ultimately to the ocean where carbon is locked up and safely stored for hundreds of thousands of years.

It’s an impressive cycle that has served — and continues to serve — our planet well. Today, however, Earth’s mineralization cycle is unable to keep up with the billions of tons of excess carbon that we need to remove from the atmosphere. 

That’s where enhanced rock weathering comes in.

The practice of ERW doesn’t reinvent the natural mineralization cycle. It speeds it up by crushing and transporting specific kinds of rock to the right environments where it can weather and lock up carbon more quickly. It's a down-to-earth way to remove a lot of carbon from the atmosphere, all by letting nature do the heavy lifting.

Measuring the Impact of Enhanced Rock Weathering

As with all carbon removal technologies, an important factor to consider is the question of how much carbon dioxide is removed during the process of ERW. Two common approaches include using modeling to predict weathering rates and directly measuring soils before and after application. 

Eion, an enhanced rock weathering provider working in partnership with Flowcarbon, champions direct soil measurement over hypothetical modeling because it takes more real-world variables into account — a critical advantage when working in a natural, open system. Direct measurement enables Eion to prove carbon removal has happened, rather than estimating using models. Eion’s patented approach directly measures carbon dioxide removed by using before-and-after direct soil samples. These samples look at immobile trace elements to show that the applied rock minerals removed CO2 from the atmosphere and transported it away to be permanently sequestered. 

Scaling the Future of Enhanced Rock Weathering

As the demand for high-quality, durable and permanent carbon removal solutions continues to grow, ERW is emerging as another valuable arrow in the CDR quiver.

ERW is one of the most exciting nature-based CDR technologies we can develop over the next few years. It’s estimated that ERW has the potential to remove about two gigatons of carbon dioxide annually by 2050, a third of humanity's goals.

While ERW has a foundation of well-understood science, more needs to be done to commercialize and scale it. An advantage of ERW is that suppliers can leverage existing industries and supply chains — like mining and agriculture — to rapidly scale. There is enormous growth potential in the U.S. for ERW to grow because of the monumental scale of its agricultural system. There’s no need to create enormous amounts of physical infrastructure from scratch as these systems and supply chains already exist.

Enhanced Rock Weathering in the Voluntary Carbon Markets

A defining moment for ERW arrived at the end of 2023, when Eion delivered the first quantifiable carbon removal tons for ERW to Stripe, the well-known payments platform, as part of its pre-purchase carbon removal program. Stripe has category-leading commercial diligence and scientific standards for its program, so the initial delivery of 50 tonnes of captured carbon was a pivotal test to demonstrate the process could be done end-to-end with rigor. 

Today, ERW remains in its nascent stage, meaning the next step is to grow the number of organizations choosing this CDR method as a part of their net zero strategies for its potential to deploy permanent, high-quality carbon removal mechanisms that generate premium carbon credits as well as deliver co-benefits such soil health, job growth, community support and other positive impacts.

ERW is emerging as another powerful tool for combating climate change and we expect market demand to grow, fueled by demand for high quality carbon credits. This in turn will drive technological progress, promote widespread adoption of its many uses and of course, generate more CO2 removal. 

Interested in learning more about carbon removal? Check out our Essential Carbon Capture Guides, including Biochar 101, Direct Air Capture 101 and Renewable Gas 101.

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