Those picture-like analogies may be very effective, but I immediately call bullshit. I want to know a percentage. Let's say 100% of air travel was removed, how much CO2 is that in savings, percentage-wise?
It's two percent[1]. If you just told people it was two percent, they would immediately proceed to not give a damn. Only the most dogmatic of people would be giving up a major freedom in their life just to save a theoretical two percent on CO2.