The idea of "protect the rainforest" offsets, and "avoided emissions" offsets in general, is as follows:
1. Party A is planning some carbon-emitting activity, such as cutting down an acre of forest, or operating their diesel bus.
2. Party B is also planning some carbon-emitting activity, such as operating their cement plant.
3. Party B pays party A to halt / avoid their carbon-emitting activity.
Note that nowhere in this scenario is anyone removing any CO2 from the atmosphere; they're just jockeying over who gets to keep emitting.
If you're thinking, "but merely by existing, the rainforest is actively pulling carbon out of the atmosphere", then that's a separate, complicated topic and not what I'm trying to address here. If you prefer, strike out "preserve an acre of forest" and substitute "replace my diesel bus with an electric bus".
> what happens when all of the Amazon offsets have been sold and I still want to emit CO2?
Again, to avoid getting bogged down in complicated analysis of the carbon dynamics of forests, let's focus on the diesel-bus example. Each year, I can pay the bus owner to continue leasing an electric bus, rather than the diesel bus, for that year. I can keep "offsetting" my cement plant forever.
> Avoided emissions are when I pay my brother to clean his room. Only one approach can lead to a tidy house.
What if you have to pay your brother two clean two rooms. You are right that just offsetting your own emissions doesn't get us to carbon zero, it sort of gets us half way there (provided it actually works of course). If instead everytime you're emitting CO2 you're not just responsible for offsetting your own CO2, you're also responsible for rolling it back. If you want to be part of the problem, you'd have to be part of the solution as well.
Anyway that's in the hypothetical situation where we want to have carbon offsets be the driver of solving the entire climate crisis. I don't think that's the main idea. The main idea is just to be a privatized hedge on carbon tax. A carbon tax could be the other half, or the other half could just be a general tax for example on CO2 positive products.
My original point is at some point you're going to run out of bus operators that can lease electric buses. All the non-electric buses also have to offset their carbon emissions after all. At some point all the avoidable carbon is bought up and offset, and the only way you can continue to buy offsets is by buying more expensive methods such as clean energy generation or even sequestration. What is triggering my math concern in your article is that your examples involve an infinite amount of offsets being available.
Maybe there's enough electric buses for the first cement factory, but what about the second cement factory, it will have to compete for the offsets with the first one, raising the cost of the offsets, enabling innovation where possible (provided again the certification works well enough).
1. Party A is planning some carbon-emitting activity, such as cutting down an acre of forest, or operating their diesel bus.
2. Party B is also planning some carbon-emitting activity, such as operating their cement plant.
3. Party B pays party A to halt / avoid their carbon-emitting activity.
Note that nowhere in this scenario is anyone removing any CO2 from the atmosphere; they're just jockeying over who gets to keep emitting.
If you're thinking, "but merely by existing, the rainforest is actively pulling carbon out of the atmosphere", then that's a separate, complicated topic and not what I'm trying to address here. If you prefer, strike out "preserve an acre of forest" and substitute "replace my diesel bus with an electric bus".
> what happens when all of the Amazon offsets have been sold and I still want to emit CO2?
Again, to avoid getting bogged down in complicated analysis of the carbon dynamics of forests, let's focus on the diesel-bus example. Each year, I can pay the bus owner to continue leasing an electric bus, rather than the diesel bus, for that year. I can keep "offsetting" my cement plant forever.