Rock Solid Climate Mitigation: The Race to Accelerate Mineralization
Enhanced rock weathering is one approach to mineral carbon removal, accelerating a natural process in which CO₂ reacts with alkaline minerals to form stable carbonates. By grinding silicate rocks and spreading them across agricultural land, rainfall helps dissolve the material and drive reactions that capture atmospheric CO₂. The carbon is ultimately stored as dissolved bicarbonate or solid carbonates — ideally transported to the oceans, where vast volume and stable chemistry enable long-term, durable storage.
One of the most promising ways of capturing carbon already exists at an enormous scale — and always has. That’s because it’s natural, not manmade: the Earth itself locks CO₂ away by reacting it with alkaline rock. This process, called mineralization, has been quietly scrubbing the atmosphere for billions of years through the slow weathering of alkaline minerals. Unlike trees or soil, which can release carbon back into the air through fire or decay, mineralization stores CO₂ for millennia — even up to millions of years. The challenge? Nature works on a geologic timescale — far too slow to meet today’s climate deadlines. That’s why scientists and startups are racing to accelerate the process: grinding reactive rocks, injecting CO₂ into rock formations, even enhancing the ocean’s natural buffering capacity to lock carbon into the deep ocean. If these breakthroughs scale, they could unlock one of the safest, most permanent carbon sinks on the planet — and play a pivotal role in stabilizing our climate.
The Path We’re On
Carbon is great — until it isn’t.
Carbon is fundamental to life. It forms the sugars and proteins in our bodies, and it powers the engines of our economy. Burn it, and you get energy. The problem, of course, is that it leaves behind carbon dioxide (CO₂), a stable gas that builds up in the atmosphere and traps heat.
Normally, these emissions are balanced by natural carbon sinks like forests, soils, and oceans, which absorb CO₂ through processes like photosynthesis and rock weathering. But over the past 150 years, CO₂ levels have risen by about 50%, from around 280 parts per million (ppm) before the Industrial Revolution to a record-breaking 420+ ppm in 2024.
It’s a monumental problem. To solve it, innovators are turning back to nature.
Today, human sources of CO₂ overwhelm nature’s carbon sinks, which can only absorb about half of what we emit. But what if we could harness a process that’s as natural as carbon itself to capture humanity’s excess emissions?
We can. And one of the best ways to do that is by mimicking a natural process called mineralization.
What is mineralization?
Mineralization is a natural process that has existed for billions of years. The key to this process is alkalinity, which is the opposite of acidity: it’s a measure of how much a substance can neutralize acids.
When CO₂ dissolves in water, it forms carbonic acid. This acid readily reacts with alkaline minerals like basalt or olivine, forming solid carbonates (basically, rocks). These carbonates can store carbon for thousands to millions of years, making mineralization a highly durable way to remove CO₂ from the atmosphere.
Today, rocks — including the Earth's crust and upper mantle — store orders of magnitude more carbon than the atmosphere, oceans, or biosphere combined, all due to the process of mineralization.
The great thing about mineralization is that it actually wants to happen, because of the chemistry involved. CO₂ is already in a low-energy state, which makes it hard to transform into something else without adding energy. But the mineralization reaction, and the formation of carbonates, is what we call thermodynamically downhill. We couldn’t stop it if we tried.
The challenge? Making it happen faster. In nature, these processes takes thousands to millions of years — too long to be of much use in meeting urgent climate goals.
In addition to locking carbon into solid rock through mineralization, the ocean stores vast amounts of carbon in dissolved form. When CO₂ enters seawater, it reacts to form bicarbonate and carbonate ions — a process governed by the ocean’s natural alkalinity. Because the ocean covers 70% of Earth’s surface, even small changes to this chemistry could have enormous climate implications. Ocean Alkalinity Enhancement (OAE) proposes to increase oceans’ capacity to store carbon by adding alkaline materials to seawater, accelerating the same core chemistry that drives mineralization on land. While carbon is stored primarily as dissolved bicarbonate rather than solid minerals, the mechanism is closely related and could enable long-term storage. However, OAE remains an early-stage concept. Major questions remain across the entire value chain — including which minerals are most suitable, how they should be sourced and processed, how effectively they remove carbon, and how to ensure deployment is environmentally safe for marine ecosystems.
A New Way Forward
Fast-tracking Earth’s slowest carbon cycle
Mineral carbon removal is rooted in natural chemistry — but scaling it to gigaton levels will take focused innovation. The core challenge is unlocking enough alkalinity to make mineralization work fast, affordably, and at planetary scale. That means not just accelerating the reaction itself, but rethinking how and where we source the materials that make it possible. From discovering new deposits to repurposing mining byproducts, innovators are now turning to the gritty work of building the supply chains, processing technologies, and measurement tools needed to make carbon rock-solid — literally.
Innovation Imperatives
Further develop discovery and processing solutions for gigaton-scale sources of alkalinity
It’s possible to accelerate mineralization at scale by identifying and processing massive sources of alkaline material, from naturally occurring rocks to industrial byproducts. Mining waste streams like mine tailings and industrial slags are one promising source, offering a way to repurpose existing materials without additional extraction — though many contain trace metals or other contaminants that must be carefully managed. Reaching multi-gigaton scale will likely require unlocking new primary sources of alkalinity as well. By improving how alkaline inputs are sourced, prepared, and delivered, innovators can make both enhanced rock weathering and ocean alkalinity enhancement far more effective — and unlock a scalable pathway to durable carbon removal.
Build reliable MRV for open-system carbon removal
Open-system approaches like enhanced rock weathering and ocean alkalinity enhancement remove CO₂ in natural environments where carbon flows are difficult to track. Measurement, reporting, and verification (MRV) systems are needed to prove how much carbon is truly removed and stored. Reliable MRV builds trust, creates market confidence, and enables large-scale deployment by giving investors, regulators, and communities assurance that the climate benefits are real.
Moonshots
Engineer biological or chemical catalysts that accelerate Earth’s natural rock weathering processes
Weathering is already happening everywhere — but at a glacial pace. This moonshot imagines supercharging the process by deploying engineered microbes that colonize rock surfaces and secrete mineral-dissolving compounds as part of their metabolism, or sprayable catalysts that safely accelerate carbonation reactions at scale. Instead of mining, grinding, and transporting billions of tons of rock, we could work directly with the planet’s existing crust — speeding up the reactions already underway across deserts, mountains, coastlines, and agricultural soils. If successful, catalyzed hyper-weathering could turn Earth’s surface into a continuously operating, gigaton-scale carbon sink. The scientific hurdles are formidable: reaction control, ecological safety, nutrient constraints, and verification in open systems. But if biology or chemistry could safely speed up one of Earth’s oldest carbon-removal mechanisms by orders of magnitude, the climate payoff could be profound.
The most viable solutions will:
To scale globally, mineral carbon removal must dramatically reduce the costs of mineral extraction, transportation, and application. In some cases, mineralization may also occur as part of economically valuable processes — such as construction materials or industrial byproducts that permanently bind CO₂ during production.
Mineralization depends on access to reactive alkaline materials — like olivine, basalt, or brucite — that can bind with CO₂ and form stable carbonates. Scaling up requires not only discovering new deposits but also leveraging existing ones, including mining byproducts and industrial waste. Winning approaches will identify materials that are cheap, accessible, and easy to process at scale.
Many mineralization pathways are energy-intensive, especially when it comes to mining, grinding, transporting, and reacting rocks. To be climate-positive, these processes must be powered by low-carbon energy and designed for maximum efficiency. The goal: minimize emissions per ton of CO₂ removed and ensure a favorable energy return on carbon invested.
Because many mineralization pathways happen in open systems — like farms, oceans, or subsurface formations — it can be hard to prove exactly how much carbon is stored, and for how long. Trustworthy MRV systems will be essential for regulatory approval, market confidence, and participation in carbon markets. That means building tools that can track CO₂ flow, lock-in, and permanence with scientific rigor.
Mineral carbon removal at scale requires mining, processing, and dispersing billions of tons of material across land and ocean systems. Some alkaline rocks and industrial byproducts contain trace heavy metals or other harmful compounds that, if mismanaged, could contaminate soils, waterways, or food systems. Viable approaches will prevent the mobilization of toxic elements and ensure that deployment does not introduce new environmental or public health risks — a prerequisite for regulatory approval, community acceptance, and long-term scalability.
