Electric cars bring a solution to traffic emissions causing climate change. At the same time they also solve other huge problems.
Large part of city pollution is coming from exhaust pipes. Nastiest are microparticles that cause cancer and illnessess of respiratory organs. There is no exhaust pipe in electric car.
Environmental damages caused by oil and gasoline
Oil transports are causing environmental catastrophies frequently around the world. Oil and gasoline leaks from cars are spreading surprising amounts of toxic materials to ground and ground water. Electric car doesn't use toxic fuels.
Oil reserves are drying up
With current consumption rate, reasonable priced oil reserves are estimated to last 20 to 40 years. Especially China's and India's economic growth is accelerating the consumption and oil reserves are running out faster.
Oil has enormous effect on global politics. Wars have been fought earlier too because energy reserves are running out. Currently control of oil (and other fossil fuels) is behind many conflicts. You aren't participating to heighten the conflicts by driving an electric car.
Dependency on imported energy
So few people understand that we are totally dependent on imported oil. If the oil wells would dry up, almost all traffic would stop and that means also transporting goods and groceries. If we would quickly increase renewable energy production (hydro-, wind-, biowaste- and solar power) and produce the "fuel" to our cars, the oil dollars would stay home.