But convincing the entire population of the world to set their thermostat 1 degree higher during the summer months would have a 1000x multiple impact on a 40x shorter time scale than if every one of those people planted a tree.
The spirit of my comment is that in general people LOVE the path of least resistance.
Ask the average person about combatting climate change and their response is "plant more trees".
Because that's easy, shit you can pay the gardener to do it or donate $10 to a plant the tree collective and feel instant gratification with no sacrifice.
Vs the highest possible impact solution which is cutting personal consumption - even a little bit!
This confused me for longer than I'd care to admit, but now that I get it, I'd just say that a much smaller proportion of 'the entire population of the world' - even the developed world - has AC than it might seem to an American perspective.
You can't ask people to set their thermostat 1 degree warmer every year for that 40-100 years. You can expect there to be scope for continued tree planting for decades.
Neither is a sole solution, but both are part of a holistic, reasoned and coordinated journey to carbon neutrality.
I agree with the point that planting 100 trees should not leave anyone feeling they've done their part. Repeating the math until we're blue in the face is what helps there I guess.