Trump pulls out of Paris climate accord, page-38

Yes CO2 is part of the environment but the reality is there needs to be a balance, the environment can handle a variation of co2 levels but how much can it handle before it has a detrimental effect. It could go the other way and we don't have enough co2, if that was the case we would need to take action to increase it.

H2O is essential but rising sea levels would have a big impact.

IMO just focusing on CO2 is a bit misleading, in my mind it's the over all emission from burning fossil fuels that should be the focus.

Yes the earth's climate has changed naturally over it's history and will continue to change but IMO it's a bit naive to think human activity has little or no impact