Can high speed rail offset its embedded emissions?

The purpose of this paper is to analyze the climate benefit of investments in high speed rail-way lines given uncertainty in future transport demand, technology and power production. To capture the uncertainty of estimated parameters, distributions for the annual traffic emissions reduction required to compensate for the embedded emissions from the construction of infrastructure are calculated using Monte Carlo simulation. In order to balance the annualized emissions from the railway construction, traffic volumes of more than 10 million annual one-way trips are usually required. Most of the traffic diverted from other modes must come from aviation and the project cannot involve the extensive use of tunnels. In sparsely populated regions it may be, from a climate point of view, better to upgrade existing lines and to try to make people substitute air travel by modern telecommunications, rather than investing large amounts of resources in enabling people to travel faster and more often.