CLIMATE change experts have claimed in a report released today that the controversial ‘black route’ chosen by the Welsh Government for the M4 relief road will lead to an increase in carbon emissions.

The report, commissioned by Wildlife Trusts Wales and presented to the Climate Change Commission Wales (CCCW), comes as the Friends of the Earth Cymru await a verdict for their judicial review over the route.

The environmental organisations have questioned whether the Welsh Government properly assessed alternatives when deciding to go ahead with the £1 billion motorway through the Gwent Levels.

Barrister Jonathan Moffett, appearing for the Welsh Government, argued at the High Court sitting in Cardiff earlier this month that it would be a waste of public money to assess the environmental impact of all options, as many did not deal with the congestion issue and therefore were never going to come to fruition.

He insisted the Welsh Government acted lawfully in its decision as only routes across the Gwent Levels solved the congestion problem.

The report by Professor Kevin Anderson and Dr Steven Glynn concludes that this preferred route will “almost certainly lead to an increase in total carbon emissions”.

It also states that “it is evident that insufficiently rigorous analysis has been presented to appropriately address the implications of the M4 proposal for the total level of greenhouse gas emissions.”

Professor Anderson and Dr Glynn highlight three sources of greenhouse gas emissions that they claim the Welsh Government failed to take into account of in their deliberations, namely that new roads will generate new traffic, manufacturing will create greenhouse gas emissions and disturbance of 9km of the Gwent Levels carbon rich soils will likely cause these soils to emit potentially vast amounts of stored greenhouse gases.

The report concludes that “if the Welsh Government is to uphold its repeated climate change commitments and develop evidence-based policies informed by science it is difficult to envisage how the M4 relief road can be justified.”

James Byrne, living landscapes manager at Wildlife Trust Wales said: “The Welsh Government’s commitment to pursue the M4 significantly contradicts the government’s call for a more sustainable Wales.

“Wildlife Trusts Wales has commissioned this report in order to highlight the inconvenient truth that a new motorway will increase Wales’s contribution to climate change not reduce it.We urge the Welsh Government to seek more sustainable transport solution that reduces our dependence on fossil fuels and protects our most precious places for people and wildlife.”

A Welsh Government spokesman has previously said: “We are committed to this infrastructure project, which is of vital importance to the economic prosperity of Wales."