In 2007 the DfT commissioned a report, "Estimated Carbon Impact of a New North–South Line", from Booz Allen Hamilton to investigate the likely overall carbon impact associated with the construction and operation of a new rail line to either Manchester or Scotland; including the extent of carbon dioxide emission reduction or increase from a shift to rail use, and a comparison with the case in which no new high-speed lines were built. The report concluded that there was no net carbon benefit in the foreseeable future, taking only the route to Manchester. Additional emissions from building a new rail route would be larger in the first ten years at least when compared to a model where no new line was built.