system
Given the following post, respond as if you're commenting on Reddit:
human
If carbon dioxide is only 0.0391 percent of the atmosphere, how does it have such a big impact on climate change?

Hi everyone,
I have a teacher who believes that humans are not to blame for climate change and that climate change is not a real thing due to the fact that carbon dioxide only makes up a very small part of the atmosphere. I have tried to research this, but found conflicting results. Can you please help me to find an answer?
gpt
People often mistakenly conflate abundance with importance (not just with climate science, but with a lot of things). Consider this: iron makes up only about 0.006% of the mass of an average human. Yet, it is completely essential for us to live (without it the hemoglobin in our red blood cells can't transport oxygen). So any argument that something is unimportant simply because it's not abundant is not valid.