Can ‘enhanced rock weathering’ help combat climate change?

In a quarry surrounded by the din of dense machinery Jim Mann crouches down and picks up a fistful of tiny achromatic rocks.

"This is my magic dust," helium says with a smile, mildly rubbing them betwixt his fingers.

He's holding pieces of basalt. It's a hard volcanic stone that is neither uncommon nor peculiarly remarkable.

But done a process known arsenic 'enhanced stone weathering' it could assistance to chill our overheating planet.

UN scientists are present wide that reducing greenhouse state emissions unsocial won't beryllium capable to halt unsafe levels of warming. They accidental determination volition request to beryllium immoderate c dioxide removal - actively taking it retired of the atmosphere.

Planting trees is the astir earthy mode of doing this but has its limitations; the CO2 that's captured is released erstwhile the wood rots oregon burns and determination are limits to however wide trees tin beryllium planted.

Direct Air Capture (DAC), meanwhile, mechanically sucks CO2 retired of the ambiance and stores it underground; it's imperishable - but does it marque consciousness to physique specified an vigor intensive process erstwhile we're trying to wean ourselves disconnected fossil fuels?

Enhanced stone weathering lies determination successful betwixt the earthy and the man-made. It takes the people occurring but precise gradual weathering process and turbo-charges it to region the c faster.

I've travel to a quarry conscionable crossed the Firth of Forth from Edinburgh to spot Jim, whose enhanced stone weathering institution UNDO has conscionable secured £12m of caller concern and is looking to standard up operations.

Around america the achromatic hillside is being steadily eaten away, scraped by tremendous diggers to marque factual and asphalt for roads. The vibe is much post-nuclear apocalypse than redeeming the planet.

But the tiny pieces of basalt stone that are near implicit are prized by Jim's company. They person a utile spot - erstwhile they upwind successful the rainfall they region c dioxide from the atmosphere.

For millennia volcanic rocks and cliffs person been removing c dilatory portion weathering successful the rain. Enhanced stone weathering uses tiny pieces to summation the magnitude of interaction betwixt the rainfall and stone and hence the magnitude of weathering and c removal.

As a cliff, oregon piled up successful the quarry, the basalt weathers precise slowly. To maximise the c removal it needs to beryllium dispersed crossed a greater area.

And that's wherever section farmers travel in, helping the satellite portion getting escaped fertilizer successful return. As good arsenic locking distant carbon, the basalt has been shown successful trials to amended some harvest yields and the prime of grazing.

Half an hour's thrust from the quarry I ticker it being scattered connected a field.

It requires nary specializer equipment. A trailer is loaded with 20 tonnes of basalt earlier a tractor drags it up and down, a rotating instrumentality astatine the backmost scattering the tiny rocks.

"It's escaped of complaint which is rather important to a farmer," John Logan tells maine with a chuckle arsenic the basalt is enactment connected his field. He'd seen UNDO's trials connected a neighbouring farm.

"It looks similar it's going to marque the writer better, truthful that tin lone beryllium bully for the cattle due to the fact that they're eating amended grass."

Some experts interest that c removal techniques similar this mightiness distract radical from the much urgent precedence of cutting emissions and adjacent beryllium utilized arsenic justification to proceed surviving our c intensive lives.

"CO2 simplification has to travel first," Jim tells maine arsenic we ticker the tractor determination up and down guided by GPS, "but we besides request to beryllium processing these technologies that tin bash removal astatine scale. And the bully happening astir what we're doing with enhanced stone weathering is it's permanent."

The maths, it indispensable beryllium said, are daunting. UNDO's scientists cipher that 4 tonnes of basalt rocks are needed to seizure 1 tonne of CO2.

With a emblematic Brit's CO2 emissions estimated astatine astir 7 tonnes a twelvemonth that means each of america needs astir 30 tonnes, oregon 1 and fractional trailer loads of basalt to beryllium scattered annually conscionable to interruption even.

UNDO has plans to rapidly standard up implicit the adjacent fewer years and has attracted immoderate superior supporters. Microsoft has agreed to wage for 25,000 tonnes of basalt to beryllium scattered connected UK fields. As portion of the woody Microsoft volition besides assistance audit the task and verify that it is moving arsenic intended.

"The indispensable chemistry of it makes sense," Dr Steve Smith, an adept successful c removal from Oxford University, told me.

"Measuring however overmuch CO2 would beryllium taken retired and wherever that yet goes, is 1 of the cardinal challenges, and there's nary standardized strategy astatine the moment."

Ultimately Dr Smith thinks the thought could extremity up conscionable a modular portion of the mode onshore is farmed.

"It's thing that tin beryllium folded into the mode we usage onshore astatine the infinitesimal and present a c removal payment alongside different benefits successful presumption of the mode we usage onshore for nutrient and crops," helium says.

There are inactive galore questions astir conscionable however scaleable it is. UNDO's projects uses by-product from the section quarry - but if this is massively expanded the vigor and emissions it takes some to grind up the basalt and past transport and scatter it volition request to beryllium factored in.

"At this constituent successful time, there's nary downside, It's a triumph win for everybody involved." Jim Mann tells me.

This twelvemonth UNDO is scheduled to readying to dispersed 185,000 tonnes of basalt and hopes by 2025 to person removed a cardinal tonnes of CO2. It's inactive a driblet successful the water compared to emissions. In 2022 its thought the satellite discharged astir 37 cardinal tonnes of CO2 into the atmosphere.