Hybrid Cars are inefficient, and does not change the fact that mankind is using up the earth's natural resources. You can't say growing corns all over the planet will not cause any drastic changes on the condition of the planet... No, the solution is not hybrid cars that use ethanol, but still uses fossil fuels. This will only cut down on Gasoline usage and it'll be many years before EVERYONE converts to Hybrid Cars... Hopefully the earth's resources aren't dried up by then.
The answer to this "global warning" is probably the use of resources that don't dry up.
Water>>Hydrogen is NOT the answer to that because then, we are making our car run with the resources that we truly need: Water. Same thing as ethanol where we are using up precious, fertile land to grow toxic plant needed to run cars. That amount of land can be used to regrow severed trees, to recultivate real corns into the ground, and to give it to the hungry individuals across the globe.
Now, you're probably thinking: "Well, by using hydrogen, we only let out water! So in the end, we are not using any resources at all!" That may be true, but where would the water be? Certainly not in large reserves! No, water will be scattered across the country, probably dehydrated into the air or soaked into the ground. Do you think we have the technology to concentrate mass areas of water vapor into drinkable water? Not at the moment, and certainly not in 10 years where gas prices cost as much as diamonds.
How about solar? Wouldn't that be more efficient? Obviously since its a resource we are not using directly, and there is too much of it on this planet anyway! The answer to global warming is not to reduce heat, but to make use of it!

Nyah-Nyah-Nyah!
Oh, and if you read all that, you can add a couple of points to your AR list. lol