You exhaling carbon isn't causing climate change. Those carbon atoms came from your food, or from your food's food, which was a plant, and the plant got the carbon from CO2 in the air. You breathe it out, it goes to the plant, you eat the plant, and you breathe it out again. This is the carbon cycle.
The reason we have climate change is the we're extracting carbon from geologic formations where it's been trapped for millions of years. There is no carbon cycle: It gets extracted, burned, the CO2 goes into the air and stays there (maybe in 10 million years more oil and coal will form, but there are reasons to believe these processes are no longer occurring.)
The reason we have climate change is the we're extracting carbon from geologic formations where it's been trapped for millions of years. There is no carbon cycle: It gets extracted, burned, the CO2 goes into the air and stays there (maybe in 10 million years more oil and coal will form, but there are reasons to believe these processes are no longer occurring.)