We're nearing the point past which we may not be able to control global climate change without really drastic measures. E.g., there are serious proposals for flying planes all over the world that release microscopic reflective particles into the upper atmosphere in order to block sunlight; these are desperate attempts which will have further consequences we can't easily predict.
We need to do everything we can to control greenhouse gas emissions, and one of the biggest changes necessary is to how we get around (and the energy infrastructure vehicles rely on). We'd probably be a lot happier with more public transportation and less smog, too.
The most effective solution would be to combine these policies. Governments would require drastic improvements in fuel efficiency for gas-powered vehicles, while investing in renewable-powered electric car infrastructure. At the same time, cities would overhaul their public transportation systems, adding more bikes, trains, buses and ride-shares. Fewer people would own cars.