Rant alert!
So, as usual: we're all doomed. If it isn't that comet that's heading for earth and is expected to pass within lunar orbit in 2036 that finishes us off, it'll be our own doing in the form pollution beyond repair. Now, I'm not saying we shouldn't be watching the environment - I'm just not convinced that what's being done makes sense. The following are all thoughts on comments made in the media, or recent popularised developments.
First off: The cars, but more importantly, the trucks themselves. Recently there was news coverage of a trucking convention - a show where the latest developments in trucks were showcased. It featured a hydrogen truck, and a hybrid truck. Both of them weren't too popular (yet) and a critic mentioned that it was all show anyway - nothing ever changes and trucks were the most polluting vehicles on the road, using 1 litre of fuel to travel 3 km (1:3). This is, of course, a bad argument as to why they are so polluting. Say a truck carries 25 tonnes of freight, and a car can carry half a tonne (crude estimates). If you have a very fuel-economical car it might do 1:25 (optimism ain't dead yet). To carry 25 tonnes, you need 50 cars, which would be equivalent to a single vehicle doing 1:0.5. In other words: a truck is more efficient than a car.
Hybrid cars and especially hydrogen vehicles, combined with new plans by Dutch ministers, do solve overcrowding problems in the Netherlands. A large percentage of cyclists has no clue about traffic safety, and many use headphones on the bike. Combine this with very silent tires (the ones that NL wants to make compulsory) on silently running electrical cars...
In the above rant fuel already features a prominent role. But there's more. Hydrogen is all nice and dandy, but it is only used as an energy store (as any fuel is merely a store). The question is: where do you get the energy from to create hydrogen? If you're burning fossil fuel to get this energy, you're just geographically shifting the pollution. So aside from the fact that hydrogen is hard to come by at present - it also requires a large investment in durable energy.
One source would of course be solar energy (according to pop-sci channels the earth takes up 8 times more energy then we need on earth - although I wonder how much we need to keep the earth warm). One way of harnessing this power is by - well let nature do it for you. Grow plants, harvest plants, convert energy stored in sugars within the plants. In most cases this is done by converting sugars to ethanol, which burns well and can be used to power vehicles. Brazil started a huge biofuel project in the 70's, and it's still running. They use sugar cane. The US uses corn, and went from no usage to moderate usage overnight. The corn price tripled overnight, meaning that in countries like mexico the poor could no longer afford their food and the meat prices doubled on their own market. Also, the way that it's being grown and refined, may actually cause more pollution and may cost more energy than it's yielding. This is certainly the case for palm oil, a lot of which comes from Indonesia. The problem here is that the land on which the palms are being grown are being cleared by burning down the natural forests of the country. As far as carbon emissions go, this is worse than traffic.
As a final, not so directly related note: Discovery Channel is opting for the 'most of us will be dead soon anyway'-approach. Their future cars programme is advertised with a short that acts as if it's selling a car to you. You being number 48095 or something 5 digit like. Seeing as they indicate a globalised economy (the car is 2 million credits) you'd expect that ID numbers would also be global. In other words - they don't expect more than 100000 registered people by then. I guess that'll turn out to be the most interesting future vision the programme will have on offer.
