Carbon Footprints of Active and Non-Active Transport Modes: Hierarchy and Intergenerational Narrative Analyses

This paper aimed to (1) develop a hierarchy for understanding the impacts of active and non-active transport modes on the environment and (2) analyse the adoption of active transportation between older and younger people. A narrative review with two parts was adopted to develop the hierarchy. In the first part, a framework was adopted to map active and non-active transport modes onto three operational boundaries of greenhouse gas emission to develop the hierarchy. In the second part, an intergenerational theoretical framework was developed to analyse the adoption of active transportation between older and younger people. The review suggests that the only active transport modes with no or negligible carbon footprint are walking, running, and swimming without a product that adds to atmospheric greenhouse gases. The evidence that younger people perform higher active transportation behaviour is inconsistent and is, therefore, inconclusive. This review suggests a need for manufacturers to prioritise the production of active vehicles (e.g., wheelchairs and scooters) that are biodegradable, recyclable, and small.