What are two chemical compounds and one chemical reaction that are related to climate change?

If it wasn't obvious, the two chemical compounds must be in the equation related to climate change.

Methane, in which four hydrogen atoms are bound to a single carbon atom, is an example of a basic chemical compound ...

A water molecule is made up of two hydrogen atoms and one oxygen atom ...

mercury (Hg) Mercury (chemical symbol: Hg) is the only metal element that is liquid at room temperature.