The article mentions ocean anoxic events as possible markers of civilizations that ended in disaster. But the opposite might be even more fascinating to ponder.

The article mentions ocean anoxic events as possible markers of civilizations that ended in disaster. But the opposite might be even more fascinating to ponder. What if there was a civilization ~2 billion years ago that thrived in the oxygen-poor environment, who accidentally unleashed cyanobacteria upon the world? Kinda like how we're recklessly dumping CO2 into the atmosphere, but on a much grander scale. Life would have had to re-evolve from the unicellular stage, and all evidence of the oxygen-dumping civilization would have been erased by geological forces by now.