How much energy will this require?
How will we generate it?
Will generating that energy produce CO2 or other problems?
What resources are we going to need (chemicals, etc.)?
How are we going to extract or produce them?
How much energy is that going to require?
How are we going to produce that energy?
Will generating that energy produce CO2 or other problems?
A common misconception is that humanity added a bunch of CO2 in a couple of hundred years. That's not true. It took millions, if not billions of years. Sure, in therms of use using petroleum, yeah, we did it in a couple of centuries. However, the reality of this fuel is that it took billions of years to create. THAT is what we burned; billions of years of stored energy.
That was the other revelation I had during my research. We are looking at this with the wrong time scale. In a couple of hundred years we burned millions or billions of years worth of stored energy. And to clean-up that mess you need far more energy than what it took to produce the mess in the first place.
Imagine how many trees, plants, animals and solar energy went into creating the petroleum we burned. That's the start of the scale of the problem we are trying to fix. In other words, we can't fix it. Not without making a much larger mess.
That would be true if the only way to remove CO2 from the atmosphere were to run "combustion in reverse" to turn carbon dioxide back into hydrocarbons.
That is not the only way, though. Enhanced silicate weathering is attractive because it turns atmospheric CO2 into chemically stable condensed phase compounds, without the huge thermodynamic cost of reversing combustion. The energy cost of enhanced silicate weathering (though still large in absolute terms) is greatly reduced compared to combustion-reversal because it's just accelerating the kinetics of a thermodynamically favorable natural process.
MgSiO3 + CO2 => MgCO3 + SiO2
This is a sketch of the geological carbon cycle [1], the same thing that eventually (100,000 years from now) would remove the excess CO2 from the atmosphere. The idea is to accelerate the drawdown by pulverizing silicates so the above surface-area-limited reaction goes faster.
See e.g. "Enhanced weathering strategies for stabilizingclimate and averting ocean acidification"
https://csas.earth.columbia.edu/sites/default/files/content/...
[1] "The Global Carbon Cycle: Geological Processes" Section 3.6
While you are right in that the process is not combustion in reverse, the reality of the matter is that it much worse than that. Massively worse.
We haven't even gone to the other elephant in the room: Australia. I hope someone eventually publishes an honest accounting of the CO2 that was released into the atmosphere through these fires. My guess is it easily negates decades of clean energy and other mitigation technologies.
I didn't get into it in my original comments. There are two questions everyone should ask when looking at the 800,000 year CO2 concentration chart:
1) How/why did CO2 levels rise?
2) How/why did CO2 levels drop?
These are fundamental questions anyone with a science background should ask almost immediately. The answers, at a basic level, are simple:
1) Massive continental scale fires burning for thousands of years. Remember, no fire dropping helicopters.
2) Storms, rain, water, hurricanes and, yes, trees and vegetation growing over thousands of years.
So, stuff burned for approximately 25,000 years for a 100 ppm increase and stuff grew and rain fell for about 50,000 years to capture the CO2 that was created.
The bottom line is that anyone claiming that we can do 1000x better than if humanity left the planet they are going to have to explain, in great detail, how it is that they know Zeus so intimately that he will grant them magical powers. And I don't think this is an understatement at all.
BTW, the only intelligent proposal I've seen is to plan trees like our lives depend on it. Seriously. Simple tech. We know how it works. We know what it does. And, if we have the water, we know how to grow them. This won't solve the problem any faster but it is likely to make things better. All we have to do is figure out how to prevent our massive new forests from burning, because, in that cases, once again, we will have made the problem een worse. Here's an article on that one:
https://www.livescience.com/65880-planting-trees-fights-clim...