We put in the atmosphere roughly 50 billion tons of CO2-equivalent per year. About half is removed by forests and the ocean, but we are still talking tens of gigatons.
Humankind produces very few things in gigatons per year numbers. Obviously (and sadly) CO2 is one of them. Coal, petroleum and natural gas are part of this family too, multiple gigatons each.
There are 4 agricultural crops that we produce in gigatons per year: sugar cane, corn, rice and wheat.
And then there's cement and iron. About 4 gigatons and 2 gigatons per year each. Cement is mixed with sand, gravel and crushed stone to produce concrete. We make about 30 gigatons of concrete per year.
Everything else we make is in numbers less than 1 GT/year. The next 2 things are fertilizers and plastics, maybe about 0.5 GT/year.
I'm saying all these things to set the scene for the proposed olivine use.
What is the idea here? That we will create an entirely new industry that will produce a new material (olivine) in quantities larger than anything any other industry produces, with the few exceptions mentioned above? All the industries I mentioned did not spring overnight, they had been around for hundreds of years.
Is the idea to create a new industry that grows at triple digits every year for a few decades? Because if this is not the idea, then I don't think this whole thing would make a dent.
I apologize for sounding a bit brusque, but I don't see how this thing makes any sense from the numbers point of view. These guys in the article are talking about 500 m3. How do you get from 500 m3 to billions of m3? Billions per year.