Original publication is here .
A commentary in Nature here.
Dockless shared e-scooters are touted as a solution to the last-mile problem, a means to reduce traffic congestion, and an environmentally preferable mode of transportation. While these e-scooters have no tailpipe emissions, full consideration of the life cycle impacts is required to properly understand their environmental impacts.
Our study differs from previous research by conducting a full LCA to address the environmental impacts associated with the materials, manufacturing, transportation, charging, and end-of-life for shared dockless standing e-scooters.
Aluminium in the scooter frame and lithium in the battery must be mined, and all the vehicle’s components manufactured. Those steps accounted for about half of the greenhouse gases an e-scooter is responsible for over its lifetime. Almost as significant were the environmental costs of collecting discarded scooters and transporting them to charging stations — a task usually performed by scooter-company employees driving personal vehicles.
Using an e-scooter is more carbon intensive than walking or biking. The scooters are environmentally friendly only when people use them for trips they would otherwise take in cars.– Nature
 Joseph Hollingsworth, Brenna Copeland and Jeremiah X Johnson, Are e-scooters polluters? The environmental impacts of shared dockless electric scooters. Environmental Research Letters, 14, 8 (2019).