[thinkcontext]

> At the time, atmospheric CO2 concentration was at a whopping 3000 to 9000 ppm! The average temperature wasn’t much more than 10 degrees C above today’s

You talk like +10C is nbd. Are you aware of how much landmass was covered by water during that time?

I'm no expert but that would cause human civilization to take a dramatically different form if not outright extinction.

[wheelerof4te]

No, I'm saying that 420 parts per million is still much lower than 3000-9000 parts per million.

Also, even a number they chose is plain trolling. Of all numbers, 420 ppm is what they "calculated".