[mojzu]

Not sure if the linked articles covers it due to the paywall, but according this article [1], the estimate that carbon emissions to build it would exceed emissions is possibly overly pessimistic. Such as predicting that air and car travel will get cheaper over time and rail travel more expensive

Although if the estimate is accurate I would still hazard a guess that it could be a net positive if it successfully increased capacity/speed to the point where people considered it a viable alternative to air/car journies and it was combined with policies to reduce the costs of rail travel/discourage air and car travel where possible

[1] https://www.theguardian.com/uk-news/2020/feb/02/will-hs2-rea...

[dkarl]

I wonder if studies are systematically underestimating modal shift because it's impossible to quantify the cultural shift from a generation that saw car travel as a sign of upward mobility to a generation that sees unnecessary car travel as tasteless and harmful.