In a sense, we could say “lack of CO2 in the atmosphere” is the scarce resource which is being depleted.
( Maybe kind of like how you can think of something which can burn by absorbing oxygen, as releasing phlogiston (which is just a lack of oxygen, in a certain sense)? )
( Maybe kind of like how you can think of something which can burn by absorbing oxygen, as releasing phlogiston (which is just a lack of oxygen, in a certain sense)? )