Interestingly, I had my first real world encounter with the other end of the carbon credits just two days ago. A friend of mine told me she had tried to get her neighbours (she lives in the woods) to apply for carbon credit grants in unison. They promise not to chop down their trees and/or to protect endangered plants on their properties, and get paid a certain amount by the Mexican government (obviously nowhere near what they'd get from chopping down and selling their trees...)
You propose that if I don't do something, you will pay me because it benefits you in some way.
I agree to not do that thing and happily walk away with the cash. Everybody gets what they want. Why does it matter whether or not I was planning to do the thing?
Because they are selling them as carbon credits in carbon markets for full price per ton of CO2 using fraudulent measures of how much carbon is additionally being averted (additionality). To be clear, the bad actors are those selling the credits claiming that these properties would have been chopped down otherwise (not the property owners).
Then actors like Apple, airlines, etc. get to claim they have fully offset their supply chain despite nothing of the sort occurring because of counterfeit carbon credits.
e: And fwiw, I have done analysis of this offline as part of a personal project - based on what I saw looking at global forestry data, the evidence is strong that the vast majority of REDD (deforestation) carbon credits are fraudulent IMO - areas being sold at the cost of carbon if the whole plot was cut down despite there being effectively no risk of that.
Reality: the kids get 100 liters of water a month from a river (yeah not enough).
You: pay a contribution hoping to get them more water.
The "offset" sellers: "See those 100 liters? 5 of them are now being paid by HeyLaughingBoy. He's helping!".
The carbon was being pulled from the air anyway, but paying gives you a certificate to say your money did that. Meanwhile the net CO2 output hasn't changed up nor down. Or rather up because you're consuming something that output CO2 to make. (Philosophical argument, the product would have already been made before your purchase, unless it's something bespoke...)
