In the conversion of pyruvate to phosphoenolpyruvate in gluconeogenesis, the addition of CO2 is followed by a decarboxylation. Why would nature add CO2 only to remove it in the next step? Is this the same carbon added the same as the one removed?

I really want to know because I don’t know how global warming to supposed to contribute to these shifts in the weather–thanks!
Anyone have any links? Because I know that global warming and CO2 emission is said to contribute to climate change and instability in the weather (hurricaine, blizzards, etc.). I’m just wondering about the mechanics/science behind this.