Imagine a world-saving technology hiding in plain sight, right beneath our feet. The idea? Crushed rocks, ground-up basalt spread across fields, capturing and locking away carbon dioxide (CO2) forever. Yes, it’s real, and yes, it could be a game-changer in the fight against climate change. But before you get your hopes up, there’s a twist you need to know.
Enhanced Rock Weathering: a Potential for Global CO2 Reduction
It’s called enhanced rock weathering, and the concept is as old as Earth itself. In nature, certain rocks naturally absorb CO2 over thousands of years, slowly transforming it into harmless minerals. Scientists believe we can supercharge this process.
By crushing up these rocks and spreading them over vast swathes of cropland, CO2 could be removed from the air at breakneck speed. If applied globally, researchers say this method could potentially suck billions of tonnes of CO2 out of our atmosphere every year.
With our current energy-related emissions soaring at 37 billion tonnes annually, this technique could be the lifeline we desperately need. An entire industry is springing up around this promise, aiming to help humanity hit net-zero emissions. Sounds like a climate savior, right? Well, hold on.
Not All Soils Play Nice
Despite the mind-blowing potential, there’s a nasty hitch. When scientists tested this in a tropical agricultural soil, the results were—brace yourself—underwhelming. Despite significant weathering, the actual CO2 capture was much lower than expected. This means that soil type could make or break this technology, and predicting outcomes isn’t straightforward.
In places like the U.S. Midwest, researchers found impressive rates of up to 2.6 tonnes of CO2 per hectare per year when spreading basalt. But when the same method was tried in a sugarcane field in Australia, the numbers crashed. The CO2 removal was a shadow of what was expected, leaving scientists scratching their heads.
Are We Measuring This Right?
And here’s where things get dicey: measuring CO2 removal isn’t as simple as it sounds. The science of carbon capture through rock weathering is littered with inconsistencies and confusion. Field and lab trials show staggering variations, with estimates ranging from a paltry 0.02 tonnes to a whopping 10 tonnes of CO2 per hectare. So, what’s the deal?
Turns out, the discrepancy comes from factors you wouldn’t expect: soil pH levels, climate, and even the strength of acids in the soil. In some cases, stronger acids in the soil react with the crushed rock without actually capturing much CO2. It’s like throwing money into a carbon-removal black hole.
Climate change isn’t slowing down, and experts say we have to remove greenhouse gases from the atmosphere to avoid a climate catastrophe. Sure, cutting emissions is non-negotiable, but the brutal truth is those cuts alone won’t get us to net-zero. We need a backup plan—and fast.
Enhanced rock weathering could be our best hope, but we’re flying blind without a way to measure its effectiveness properly. Scientists are calling for more research, better understanding, and more robust methods to track carbon capture. Until then, this miracle solution remains a high-stakes gamble.
