Plants grow better with more carbon dioxide, but carbon dioxide also makes more heat (which some animals are not adapted to) and can be pretty unhealthy for humans and other animals.

The problem with climate change isn't the planet; the planet will do fine, and life has bounced back from mass extinctions like this one many times before. The actual problem is mainly with the survival of humans and other animals one may care about. I think some humans will be able to prepare enough that humans won't become completely extinct, but that doesn't mean that there won't be a huge population reduction and a world much harder to survive and thrive in.