Ironically, water vapor is a worse greenhouse gas than carbon dioxide is...so we'll have all these cars spewing water vapor into the atmosphere instead of CO2, an actually making "global warming" worse. LOLZ
Water vapor is
the worst greenhouse gas, but even if everyone in the world switched to these cars the output still wouldn't even be comparable to the amount of naturally evaporated water vapor. These things just need to be put into perspective. The water vapor we would create is a mere drop in the bucket in comparison to what's already happening.
Also, a lot of people like to point out that electric cars (plug-ins) still use fossil fuels. This is absolutely correct, but again it is not put in a realistic perspective. Equating power from a wall outlet to power made by an internal combustion engine means that you think these two sources are equally efficient. ICE motors are incredibly
inefficient in comparison to power plants that supply whole cities or even states, if for no other reason than scale. Wall power is considerably cheaper for the consumer, too.
There's still the issue of batteries, which is a MAJOR one. I'm not saying electric is the perfect solution, but it's a step in the right direction. ICE cars had to grow to what they are today, just like any other product. Electric cars should be given that same opportunity.
As far as hydrogen, that too looks promising, but it's much further out than electric. Not only do we need to build an entire fueling infrastructure but we also need to find much more efficient ways of producing hydrogen. People look at the hydrogen car and how well (and cleanly) it produces energy and think it's great, but they don't look at where the hydrogen came from. A lot of energy goes into making hydrogen, and when you look at the whole picture, it's currently not that efficient.