The 'reduced emissions' outcome of the NTS included a commitment to develop a carbon balance sheet for transport with the expectation that:
"This will present the impact of all Scottish transport policies and projects that are expected to have a significant impact on carbon, whether positive or negative."
This commitment is met by the publication of this Carbon Account for Transport (CAT). The CAT is to be used to monitor and review progress towards achievement of the 'reduced emissions' strategic outcome for transport. In doing this, it will support the development and implementation of actions to reduce emissions in accordance with the targets in the Climate Change (Scotland) Act.
The CAT itself, however, is not a decision making tool at an individual project or policy level. Scottish Transport Appraisal Guidance ( STAG) remains the process for appraising new policies and projects, with the impact on the environment being one of the five criteria considered.
Showing the level of greenhouse gas emissions, measured in carbon dioxide equivalents (CO2e), of the Scottish transport sector over time, the CAT helps explain which transport policies and projects are forecast to have the most significant influence on changes in emission levels. Measures are split between those that are infrastructure projects and those that are fiscal policies or regulatory measures. Importantly, to avoid misrepresentation of the data, the CAT does not attempt to aggregate the impact of these measures or to compare them to a business as usual baseline.
The approach of the CAT is transparent and open, outlining the expected impact of transport projects/policies on emissions to a greater extent than simply focusing on traffic growth. It will be updated on an annual basis, and should help to ensure that the Scottish Government systematically considers the carbon emissions impact of its transport decisions.