I am a climate scientist, and it isn’t very often that I feel like I get to share good news with people. Luckily, every so often good things actually do happen. I have said on this site a few times before that climate science is relatively young as a field of study, and though things may feel bad at times, some of the best scientists in the world are working in the background to address our major climate issues.
Four years ago right here on Hexbear I was addressing some comrades’ concerns about climate in the long term. I told them that of course the situation we are in really is terrible, but there is one method in particular that has some real potential to majorly address our climate crisis: Silicate weathering. This method has been one of the primary methods of carbon cycle management throughout earth’s history, albeit over time periods of millions of years, and all we have to do is figure out how to apply it to human timescales. Just as I predicted, that is still indeed the most promising method of carbon sequestration, and it just took a giant leap towards viability, as outlined by the study I will be talking about with you today.
(My commentary from 4 years ago if you don’t feel like following the link)
On the, “What can be done?” side, luckily you have some of the smartest and most dedicated scientists in the world working on ways to sequester carbon, and the most promising method is accelerating the silicate weathering process which is the most effective tool to combat man made climate change.
For those who don’t want to read or don’t understand, I’ll briefly summarize why this method is important and the most likely candidate:
You may be thinking “oh let’s plant trees” which is good, sure, but consider that we are re-adding carbon which was not actively in the carbon cycle back into it. A mature forest is most times carbon neutral, as carbon output from decaying biological matter is roughly equal to carbon uptake (think about the following: how could forests continue to exist in the first place if they sucked out more carbon from the air than was added to it?)
Now think where we are getting our carbon that we add back to the atmosphere from. We pull it from underground deposits. The beauty of silicate weathering is that it incorporates carbon into rocks, and thus acts as a long term storage vessel when removing carbon from the atmosphere. The big problem though is that this process happens naturally over the course of tens of millions of years as a result of plate tectonics uplifting mountain ranges and these ranges getting weathered (as implied by the name “silicate weathering”).
So now geologists and climatologists are trying to figure out ways to massively accelerate that process, which has only become a remote possibility over the last 15 years.
How it works: 
What it means in less scientific terms:
Enhanced rock weathering (ERW) in farmland is a method to sequester atmospheric carbon on medium-long term timescales. This study measured this carbon sequestration process as a way of potentially increasing crop yields while simultaneously removing carbon from the atmosphere through the silicate weathering process. Testing this process demonstrated ann improved crop yield of 8%-18% in humid regions, plus improvements in overall soil quality. Soils with higher alkalinity sequestered the most carbon, especially in high precipitation scenarios. Expanding this study to all viable farmland across China has the potential to sequester .4gt of carbon yearly, or roughly 3% of China’s yearly CO2 emissions. Economically, utilizing this method is comparable to the cost of heavy soil modification already used for intensive agriculture. The use of ERW in nutrient poor/overly acidic soils provided a comparable effect to common agricultural practices of using lime and fertilizer to decrease acidity and raise nutrient levels. Additionally, the silicates needed to conduct this process are commonly found in waste products of advanced manufacturing and industrial processes, which could mitigate the carbon impact of manufacturing, industrial, and farming sectors while also lowering expenses in each.
Utilizing this method globally, we have the ability to improve the quality of our farmland while also removing carbon from the atmosphere at relatively fast rates, all things considered. Of course, we will still need to go carbon neutral in terms of energy production, but once that is achieved we have an actual method to remedy some of the harm we have already done to earth’s climate. Our long term climate solutions, should we use this method, are possible on a scale of decades-hundreds of years (and that’s with only our currently available technology!) as opposed to the thousands of years or longer we previously thought.
If one simply wanted to maximize the amount of carbon removed from the atmosphere and ignored the agricultural aspect, would it also be possible to just have a conveyor belt carrying freshly ground rock dust with a fan blowing at it? Alternatively, if the process is too slow for that, a warehouse full of densely packed shelves, each coated in dust, with outside air being moved through it? Or does it rely on some other substance in the dirt? I'm pondering ways this could be scaled up purely for carbon-capture purposes.