Yes, it's not that every flight you don't take across the Atlantic saves 2 tons of CO2. It's that it has a 99.9% chance of saving almost none and a .1% chance

Yes, it's not that every flight you don't take across the Atlantic saves 2 tons of CO2. It's that it has a 99.9% chance of saving almost none and a .1% chance of being the straw that breaks the camel's back in causing a reduction in flights on that route and saving 2000 tons of CO2. But they're the same in expectation.