Electric vehicles are not climate-friendly, but merely somewhat less climate-unfriendly than petrol or diesel ones. There are carbon emissions from manufacturing the vehicle, and from generating electricity to charge the battery. The wider environmental damage includes pollution from mining and processing battery components, particulate air pollution from tyres and brakes, and pollution from the disposal of batteries. The very idea of a climate-friendly Hummer is a kind of Orwellian doublethink (I test-drove the all-electric Hummer. Can it win over America's EV skeptics?, 7 April).Pam LunnKenilworth, Warwickshire
