No new runways or terminals need to be built in order continue the same level of service for air travel between London and Manchester or Glasgow. Even if they needed to be built, they constitute a much smaller mass of infrastructure than several hundred miles of high speed rail plus a dozen stations.

“… the study takes into account not only emissions during operations, but also CO2 emitted in the building of a new HSR line, the pollution from cranes and bulldozers, building new stations, and everything else required in laying down new tracks.”

But the analysis does not seem to take into account the emissions from building the airport and runways, the vehicles operating on the taxiways and apron, or the terminal buildings.

1) The areas of the US where HSR is most appealing are every bit as densely populated as anywhere in Europe – The NE Cooridor, Chicago Spur routes, and LA-SF/Central valley. High speed rail is only appropriate for routes of less than about 400 miles of which there are many in the US

2) It’s about much much more than carbon emissions. It’s also about sanity in transportation and ending an infrastructure that’s dependent on the automobile. Being able to walk to a train station and get to another city is immeasurably greener than sitting in a traffic jam for hours on a freeway – measured by carbon, human productivity, land wasted by pavement, happines, you name it!