Why should we do anything?
Unless you live walking distance from where you need to go, we all need to get from here to there. The traditional petrol-fueled car produces gases which if exclusively breathed in, would kill someone. This is just let out into the atmosphere, not to mention the damage caused through drilling for the oil *cough*BPoilspill*cough*.   

~ Solutions ~

Walk or ride a bike for short distances instead of driving
Don't have to pay for transport or petrol.
Good exercise, clean conscience.
If it's a bike, need to buy a bike and helmet, or comfortable walking shoes first.

For longer distances, catch public transport or ride a bike
One really great effect is that you can multi-task, like doing assignments on a train. I tried glancing down at a paper I needed to read while driving - it wasn't comfortable!
Looking at daily, weekly, monthly or yearly tickets, you can make quite a saving and don't have to pay for petrol or car maintenance, plus registration, etc.
No additional petrol fumes emitted.
Chances are that you would have to walk to a bus stop or train station, so there is that bit of extra exercise. Especially if you're on a bike. So if you incorporate exercise into your day, it is like multi-tasking. And you'd go faster and harder if you have a deadline, like a train or bus leaving.
Have to pay to ride on public transport - it's the weekly tickets that offer good savings (at least in my area). Pensioners have good daily rates, though. And you'd need to buy a bike first, if that's your method. As well as a helmet!  
Can take longer, but if you multi-task, it's not noticeable.

Experimental - waste products as a fuel source Pee-powered car
Plenty of that!
Still experimental, unsure of the costs to convert, and possibly would meet resistance from corporation since it means they would be making less money.

Experimental - Solar-powered plane! e.g., Boeing's solar-powered UAV
Can stay in the air for 5 years!
Clean and sustainable source of energy - being the sun. And less dependent on the weather if can fly above the clouds.
Still experimental, would cost a lot to produce but would be worth it in terms of fuel savings, is being tested in 2013.