This study estimates of the life cycle greenhouse gas inventory for construction of high‐speed rail infrastructure from San Francisco to Anaheim indicates it will result in 2.4 million metric tons of CO2 with material production comprising 80% of emissions and transportation of construction materials, 16%. While tunneling and aerial structures account for only 15% of the route’s length, they are responsible for 60% of emissions. Based on estimates of avoided emissions from operation of the system of just over one million metric tons of CO2 per year, construction emissions would be recuperated in about two years and their global warming effect in about six after services begin. This range of recuperation times is relatively short given the long‐life of the constructed infrastructure. Avoided emissions estimates are dependent on ridership and if low ridership lead to a 75% decrease in offset emissions, recuperation times may increase to more than 20years.
