We can (and currently sort of have to) extract energy from fossil sources because our economy runs on hydrocarbons but we will need to expend more energy later to put the extra carbon back where it belongs. The energy we will expend for this in the future has to be renewable.
We are basically borrowing from our future selves and will have to pay back the debt one day.
It's like driving accelerating train without the breaks and hoping that someone builds tracks fast enough that we won't derail
Sure, evolution keeps running its RNG and eventually new and interesting species will start showing up. But that doesn't replace the causal link that is lost. Today, the variety of organisms on our planet gives biologists a chance to understand how crucial mechanisms of life evolved. As we erase that history, we make biological sciences that much harder, and by extension, slow the progress of everything from medicine through biotech to chemistry and material sciences.
You're gaining a lot of energy going from CH4/etc + O2 to H2O + CO2.
You're then directly sequestering CO2 (usually in solution in a deep brine), rather than C. You need to expend energy to concentrate the CO2, but it's less than you gain from combustion.
In practice, it's more difficult to come out energy positive overall if we're capturing CO2 at atmospheric concentrations rather than from flue gases/etc at the time of combustion. Regardless, though, "driving roads in reverse" is not a good analogy. We don't need to expend anywhere remotely as much energy as was generated from the original combustion.
Is this actually a given? I mean trying to make gasoline from the atmosphere would certainly require more energy than you get by burning it, a lot more.
But I thought sensible capture proposals ran on different chemistry, possibly relying on a wet/dry cycle under which the affinity for carbon is different in the two halves. And letting evaporation (i.e. solar energy) move you from wet to dry. It's not obvious that these must use more energy than you got by burning the coal in the first place.