Fair comment. The data I am relying on is based on ice core sampling at the poles. We know, to a very high degree of certainty, what our atmosphere did for the last 800,000 years.
Taking this as to be my factual basis it is very easy to see what the planet has done and will do without humanity being around to muck things up. In rough strokes, atmospheric CO2 accumulates at a rate of about 100 ppm per 25,000 years and is reduced at a rate of, again, roughly, 100 ppm per 50,000 to 75,000 years.
This forms the basis of my assertion that erasing the entirety of humanity, our buildings and toys would only result in a 100 ppm reduction in 50K to 75K years. In other words, as far as a human scale is concerned, this might as well be forever. We might not even exist in 75,000 years.
The only way this assertion could be refuted is if someone is able to prove there is a way to take a planet-scale system and accelerate it's natural rate of atmospheric CO2 accumulation decay from 100 ppm per 75K years to something fast enough to be of practical significance to humanity.
Well, I suppose the other way to refute it would be to prove that our ice core sample data is fake or flawed in some manner. That will not happen. This quality and veracity of this data is well supported in the literature and accepted to be extremely accurate.
Without even attempting any math at all we can say the amount of energy required to accelerate planetary-scale effects from 100 ppm/75K years to, say, 100 ppm/100 years is likely astronomical in scale. And that much energy is rarely without consequences.
Remember, if we evaporate from this planet nothing changes faster than 100 ppm/50K years at best. In order to prove de-industrializing and crippling entire nations and continents would have any merit at all someone has to prove the physics and chemistry that would deliver the desired 100 ppm change in atmospheric CO2 concentration massively faster than 50K to 75K years.
This is why I am really down on the entire Climate Change business. It's a political football. Deniers are crazy and so are proponents or believers (at least politicians). They things they are talking about doing are utterly pointless and would only serve to damage countries and societies.
I mean, let's say we absolutely erase the United States from the face of the planet. Why just try to go "green", let's completely erase the US from earth. What would that accomplish? Absolutely nothing. Atmospheric CO2 concentration would continue to rise exponentially at about the same rate. It certainly isn't going to go down at all. So, what are these proponents talking about? Well, nonsense, that's what they are talking about. It has become a political tool with religious undertones on both sides.
I also spoke of us already having a technology that could be brought to bear on this issue world wide with relative ease. The questions to ask when looking at ice core atmospheric sample data are:
1- What made CO2 concentration increase?
2- What made it decrease.
The answers are simple:
1- Fires. Massive continent-scale fires. No firemen and water dropping helicopters to stop them.
2- Weather and trees. Water precipitates CO2. So, hurricanes, cyclones, storms, rains are good. They "wash" the atmosphere. And over tens of thousands of years they'd chip away at the problem.
And trees, well, trees take CO2 and turn it into, well, trees! They are a fantastic bit of technology that only requires water and soil to work! And we know how to grow trees at scale!
So, instead of a lot of the nonsense being floated out there what we have to do is:
1- Control or stop deforestation. This is terrible for the planet.
2- Plant trees like our lives depend on it. All of these lawns in front of homes in a city like Los Angeles are almost criminal when you consider they do nothing but waste water and require a guy with a gasoline powered mower and blower to maintain every week. We need to seriously consider changing the culture to plant a couple of trees in front of every home of every city wherever possible. Our cities need to look like forests to the extent possible. And there you go, CO2 sequestration using the very same technology the planet has probably used for millions of years to achieve the same kind of balance.
Anyhow, that's my humble opinion.