"climate change" here is a shorthand for "climate change caused by human emissions of CO2". I don't think the OP meant that people deny that the climate change

"climate change" here is a shorthand for "climate change caused by human emissions of CO2". I don't think the OP meant that people deny that the climate changes over time due to natural causes (actually, I think it's incredibly obvious). I have learned, though, that in a politically charged atmosphere, it is important to be very exact in choosing your words, because people are looking for opportunities to attack.