Carbon footprinting of railway embankments and cuttings: A circular framework

Abstract

There is now a consensus that global temperatures are rising and that the world is in a climate emergency. Science has proven unequivocally that there is a relationship between anthropogenic carbon emissions and global warming. Reducing anthropogenic carbon emissions to net zero by 2050 is now one of the highest priorities for many governments around the world. Network Rail (NR), as the GB mainline railway infrastructure manager, have a need to align themselves with the legal requirement to meet net zero by 2050. At present the quantities of carbon in railway geotechnical assets, in particular embankments and cuttings, are not well understood or recorded as separate entities. The research described in this paper aims to fill this gap through the accurate measurement of carbon emissions associated with railway embankments and cuttings in a business as usual (BAU) scenario. This data can then be interrogated to identify potential areas of savings. Carbon sequestration measures such as afforestation and enhanced weathering may also be deployed as part of this effort to balance the carbon in a project to net zero. This paper outlines a proposed framework to measure the lifetime carbon associated with earthworks assets and identify areas of carbon intensity (‘hot spots’). It then discusses potential solutions to reduce carbon and thus assist NR in meeting its science-based targets via a move from a linear to a resource cycle analysis, taking into account circularity principles.