If CO2 levels above 400 ppm cause a life-threatening “acidification” of oceans, and damage to the coral reefs, how did the coral reefs exist in the past, when the global average temperature was much higher, and the CO2 level was around 4,000 ppm? - TL Winslow, Pansophist master of STEM and world history

https://www.quora.com/If-CO2-levels-above-400-ppm-cause-a-life-threatening-acidification-of-oceans-and-damage-to-the-coral-reefs-how-did-the-coral-reefs-exist-in-the-past-when-the-global-average-temperature-was-much-higher-and-the-CO2/answer/TL-Winslow