One of the arguments in favour of high speed rail is that because of modal shift, it can reduce carbon emissions. However, just because some high speed rail schemes can reduce carbon, that does not mean that HS2 will cut carbon over any sensible timescale.
And in HS2 Ltd’s own documents they say HS2 will cause increased carbon emissions beyond 2086.
As with all HS2 Ltd documents that show up the scheme’s flaws, their information paper on carbon hides the fact that they expect HS2 to increase carbon before 2086 on page 5 of a 7 page document. The earlier pages cover such things as the 1997 Kyoto Protocol, the Climate Change Act 2008 and the Climate Change Plan from 2011.
The biggest influencer on overall carbon emissions from HS2 is the vast amount of emissions from building HS2 in the first place: once built, those costs are fixed. Although the HS2 Ltd document first covers potential carbon savings from operating the scheme – which includes tree planting for some reason – these are much less certain, as they depend on a whole load of other factors, such as the actual modal shift and the uptake of electric cars etc.
Or as HS2 Ltd write:
6.4 When the operational and construction carbon footprints of the Proposed Scheme are combined to form a total carbon footprint over the 60 year assessment period (plus the 10 years of construction), the residual carbon ranges between 2,140,000 tCO2e and 2,620,000 tCO2e. This includes all emissions associated with construction, operation and maintenance of the Proposed Scheme, as well as modal shift, carbon mitigation from tree planting and freight benefits from released capacity on the classic network. If the same assumptions for the first 60 years of assessment are extended for another 60 years to align with the 120 year design life of the Proposed Scheme, the footprint ranges from a surplus (360,000 tCO2e) to a saving (-230,000 tCO2e).
It’s worth noting that 120 years of operation takes us to 2145. Given that the Dft missed that laptops and smart phones might affect business travel five years ago it’s hard to place much confidence in their forecasting for a 130 year period.
A final thought is that HS2 Ltd’s carbon assessments are showing that HS2 is less and less favourable. In 2011, HS2 Ltd thought it would be carbon neutral over a 30 year period: see
The broken carbon promise of HS2. . By 2013, they were hoping that it would be carbon neutral over a 130 year period – see HS2 won’t reduce carbon this century.