A look at the full lifetime emissions of the vehicles call into question the ecological assumptions around “micromobility.” Bird boasts that its dockless electric scooters allow customers to “cruise past traffic and cut back on CO2 emissions—one ride at a time.” Its rival Lime claims the vehicles “reduce dependence on personal automobiles for short distance transportation and leave future generations with a cleaner, healthier planet.” But the mere fact that battery-powered scooters don’t belch pollution out of a tailpipe doesn’t mean they’re “emissions free,” or as “eco-friendly” as some have assumed. The actual climate impact of the vehicles depends heavily...