No one is saying any cause. Just prediction. Doesn't rising number of cars, also include electric or other alternative energy?
What the graphic is telling us is, no matter how big the effort is to switch to renewables+ev's, etc., the fast growth of emerging economies, less prone to become green as fast as, say, EU, will lead to a sustainable and even increasing use of fossil fuels.
The best scenario, in my opinion: fossil fuel prices skyrocketing + some political agreements to boost smart subsidies where there are needed, to make renewables cheaper than coal. As Google.org says, RE<C (where "RE" is renewables and "C" is coal.)
60% of EU budget goes to farmers subsidies. USA subsidizes also monocrops such as corn (leading to massive use of corn syrup, packaged food, boosting obesity.)
So less subsidies to lobbies and more to renewables. And more electric cars on the roads.
I've driven some cool EV's and I only say this: it's really fun. Waiting for the 4 new Renaults to come in 2011-2012 and, specially, a smaller-cheaper version of the Tesla Model S.
All that said, I don't own a car.
Which is why I explain the rest. Read the RE<C and be cool.
Tomle: even if we account that all EVs are filled by electricity that comes from coal, their efficiency decreases dramatically the amount of CO2 into the atmosphere. It's just CO2 from production, not from constantly burning. Cities are also better off, without smog and several diseases. Less geoestrategic issues and probably less was, but you probably don't care.
And if you live somewhere like Spain, where in windy days daily electric production for the whole country increases from around 30% wind energy to a mix that reaches sometimes 50%, you are likely to pay way less for moving and be way more sustainable than with your tar sands clunker.
If you do want links with data for all the things I say here, I can look at them for you. I write about this, so I know what I'm saying.