High speed rail has a very valuable role to play in delivering an environmentally sustainable transport system and in encouraging sustainable economic development, as long as careful design is deployed to manage the impacts of construction.

Carbon emissions

Rail, as a relatively benign transport mode in environmental terms, increasingly needs to offer a viable alternative to other modes such as air and road travel. This is true even where much of the policy response is focused on restraining overall travel demand. The Tyndall Centre, in its 2006 report ‘Living within a carbon budget’, advocated investment in capacity in faster rail services as one way to help meet carbon reduction targets.

High speed rail and aviation

One of the most valuable environmental benefits from high speed rail is that of constraining future growth in domestic aviation. Greengauge21 research, reported in The Impact of High Speed Rail on Heathrow Airport, set out that connecting Heathrow into High Speed 1 and a north-south high speed rail network would encourage a substantial passenger transfer from both domestic and short-haul European flights to surface transport.

The Eddington Transport Study estimated that the potential carbon savings from shifting domestic air passengers to a London to Scotland high speed line might be 0.5 million tonnes per annum. Over 60 years, this would be valued at £3.2 billion.

A lower-speed rail service would not achieve these benefits as rail journeys would not be fast enough to compete with the airlines. And while high speed rail will inevitably use more energy than conventional rail services, high speed services will operate using longer trains and higher average loadings, so that average carbon emissions per passenger will be comparable.

Land use effects

Constructing a new railway line will of course have environmental impacts in terms of land-take and its impact on landscape and urban areas. However, experience from High Speed 1 has shown us that these can be mitigated significantly in the design phases by building in existing transport corridors.

One positive effect from high speed rail that is often overlooked is that of encouraging development in city centres, reducing pressures to develop in the countryside. The reinvigoration of cities and the creation of lifestyles that are sustainable and not car-dependent are crucial to reducing our carbon footprint. Other transport projects, even those such as light rail schemes, often encourage more dispersed patterns of land use development – even if they benefit the city centre, they also stimulate demand and development on the urban periphery.