I believe this is true at night. Although less than they absorb in the daytime.
Yes but the way he said it, he meant that is ALL they give off. I forget the context, but it was something like “animals, humans, cars, and plants expel nothing but CO2” oh yes and then he said into “this very thin layer of atmosphere”. Yes, “very thin” which just so happens to be a very thin 5000 trillion metric tons, a very thin 60 miles high, 80 if you count the very last extent. Thin my ass. Imagine a 60 mile deep ocean completely engulfing every square inch of earth. We can no more affect the composition of that than we can piss in the sea and turn it yellow.