From “Climate Change: How Do We Know” from NASA, mentioned in this article, there is a carbon level rise and fall graph which looks almost periodic. Perhaps the

From “Climate Change: How Do We Know” from NASA, mentioned in this article, there is a carbon level rise and fall graph which looks almost periodic. Perhaps the previous cases of cause and effect help us to be aware of the present situation? For example- Do we know what took the carbon dioxide level high during 400000 and 320000 years ago, aftermath and things that brought the level down eventually in next few thousand years before the rise (again)? [1] https://climate.nasa.gov/evidence/ https://climate.nasa.gov/evidence/