>Fewer cars in general is the win from congestion pricing, though.
And lower VMTs (vehicle miles traveled) is also a win for the planet, it's probably the best weapon the average person has access to in the fight against climate change. Transit usage begets transit usage; more fares paid to the agency enables better frequencies and more routes, leading to more people opting to take transit instead of driving... In a well-run system, it's a positive feedback loop (and the inverse, where people stop taking transit, can also lead to a death spiral, as happened across America in the mid-20th century).
If you substitute with “don’t travel far [or at all]”, it’s a big savings. If you substitute flying 1000 miles on an airliner with “drive 1000 miles instead”, or flying US to Europe with a cruise ship trip to Europe, you’ve probably made it worse; in that regards, it’s less the mode of travel and more the total distance in these trades.
The observation that stuck with me is how much of my county's total carbon emissions are due to air travel which begins/ends at our regional airports (~3%), vs what percentage of the population flies in a given year.
The distribution of air-travel emissions, to me, seem pretty gross when juxtaposed with the number of people who are doing this travel. The incentives for business travel, in particular, seem misaligned.
I don't think you can just look at the "number of people who are doing this travel", as those same planes are also carrying air cargo and US mail. Not everyone flies, but almost everyone in the county receives mail, cargo, or benefits from same. (It would be easier to replace cargo than passenger transport with a more efficient and comparable total trip time mode of transport if such was available.)
The reason you get asked whether your USPS parcel contains hazardous substances X, Y, and Z and why the fines for violations are so stiff is partly because of passenger airline safety concerns.
Rail transit in the north east is the best in the US. But it is terrible in many ways. As someone who lives in an area that would be marginal for rail even in the great rail countries of Europe of Asia I really need the north east to develop great rail - only by bringing great rail to places where it is easy can we possibly get it good enough that it would be worth bringing to me. Instead I just get examples of why we shouldn't bother with transit at all here: when all we can see is the stupid things New York is constantly doing to transit (where the density is so high they can get by with it) there isn't an example I can point to of that would be worth doing here.
And lower VMTs (vehicle miles traveled) is also a win for the planet, it's probably the best weapon the average person has access to in the fight against climate change. Transit usage begets transit usage; more fares paid to the agency enables better frequencies and more routes, leading to more people opting to take transit instead of driving... In a well-run system, it's a positive feedback loop (and the inverse, where people stop taking transit, can also lead to a death spiral, as happened across America in the mid-20th century).