Now, I fully expected a number of excuses from the deniers, but there is one rationalization that I've found to be especially dim.
I'm not sure whether this person was being sarcastic, but it's not the first time I've heard it:
the climate changes every day and always has but only low information voters believe that CO2 is bad for the planetSure, the claim is changing every day... inching towards a hotter, more changed planet...yes.
It's the second part that's curious. The argument (in general) seems to be (if you were to look at the general usage of this argument, beyond what person stated above):
- Trees need CO2 to live
- Trees are good, therefore CO2 can't be bad, and isn't a pollutant
- Therefore, no amount of CO2 released into the environment can be bad
- Therefore, global warming is hereby refuted
I'm not sure that's the line of reasoning, exactly. There's a dense amount of extrapolation, since the people who generally make this kind of claim can't or won't explain themselves... so it's my best guess.
It'd be like saying that since we need water to live, no amount of water is bad for us.
The basic concept of pollution can extend to having excessive amounts of a thing (think "light pollution or "sound pollution")... as long as it has detrimental effects.
Sometimes, I'm not sure the global warming/climate change deniers are thinking deeply... not if these are the types of arguments we get.