The report concludes that only HS2 can provide the rail capacity needed to significantly shift travel away from polluting road and air alternatives. Notably the report also finds that HS2 contractors are already outperforming carbon forecasts, with the HS2 project acting as a catalyst to reduce emissions, and that any moves to curtail the scheme could weaken the project’s substantial carbon case. 

HS2 - towards a zero carbon future examines the carbon case for HS2, considering its impacts from construction, operation and modal shift. The independent review commissioned by High Speed Rail Industry Leaders (HSRIL) was produced by Ralph Smyth, who formerly led the Campaign to Protect Rural England's (CPRE) engagement on HS2 and was the only person permitted to petition against HS2 legislation regarding its climate change impacts.  

Smyth recommends using the net zero obligation to reboot HS2’s environmental narrative and relaunch it to coincide with the project’s tenth anniversary. He argues that the Government’s forthcoming Transport Decarbonisation Strategy should be used as an opportunity to commit to making rail the longer distance travel mode of choice through HS2. Full integration with Northern Powerhouse Rail and Midlands Engine Rail is essential, whilst the ongoing Oakervee Review must also be aligned with Government decisions to implement transport policies that will ensure complying with the fifth carbon budget (2028-2033). 

Reviewing the report, HSRIL draw the following conclusions:

• HS2 will form a crucial part of the transition to net zero. As the transport sector undertakes an irreversible shift towards net zero emission mobility, a high capacity fully electrified railway such as HS2 is essential to making this happen.
• HS2 is already outperforming carbon targets. Initial estimates of the carbon impact during HS2’s construction phase may have been vastly overestimated. For example, one of the main contractors, a HSRIL member, is delivering early works already 13% under target for carbon emissions. Outperformance of initial forecasts during the construction phase of the scheme are likely to be 20-30%.  
• HS2 is a vital investment to the decarbonisation of the UK’s transport sector. HS2 should be viewed as intrinsic to the forthcoming Transport Decarbonisation Strategy, catalysing modal shift from road to rail. HS2 will release capacity for commuter services and rail freight. 
• HS2 can play a key strategic role in climate change adaptation. HS2 will be the most reliable and resilient transport infrastructure available during increasingly frequent extreme weather events.
• Any moves to curtail HS2 will weaken its carbon case. Curbing HS2 will weaken, not improve, its carbon case by reducing the wider benefits the project unlocks from released capacity and sustainable housing development.

Ralph Smyth, author of HS2 - towards a zero carbon future said:“HS2 was proposed on the back of the momentous Climate Change Act 2008. Following the Government making a historic commitment to deliver net zero emissions, it’s time to reboot HS2’s carbon case in time for the scheme’s tenth anniversary.  

“Achieving net zero will require big changes to the way we travel. Longer journeys are the hardest to decarbonise, which is why we need to make rail the longer distance travel mode of choice. Only HS2 can deliver the capacity and journey time savings to shift many more people out of cars and planes by the 2030s, without causing a decade of disruption to our existing train services.

“The challenges of achieving net zero in the transport sector, now the biggest single source of carbon emissions, needs to be at the top of the next Government’s in-tray. Failing to join up difficult - and long delayed - decisions to tackle air and road emissions with its response to the Oakervee Review would be a huge own goal. Failing to deliver HS2 and maximise its carbon benefits could jeopardise achieving climate-friendly transport for another generation.”

Jim Steer, Director, High Speed Rail Industry Leaders, said: 

“The report makes clear the fundamental role that HS2 has to play in the UK reaching net zero. The fact that HS2 is already out performing its carbon targets is demonstrative of the industry’s commitment to making HS2 the greenest major infrastructure project the country has ever seen.”