"Geo Metro XFi engin combined a shorter duration cam, leaner fuel map, two ring pistons, and a higher final drive gear model to achieve 43 city, 51 highway per the revised 2007 EPA mileage standards."

"2008 Prius 48 mpg-U.S. (4.9 L/100 km / 57.7 mpg-imp) for city driving, 45 mpg-U.S. (5.23 L/100 km / 54 mpg-imp) for highway driving"

As I see it, there are three options:

1.) Reduced standard of living to support growing global popluation.
2.) Technology supporting growing population and standard of living.
3.) Reduced global population to support growing standard of living, either voluntarily or by the traditional methods of famine, disease, and war.

We are pursuing a mix of the first and second options, and Mother Nature is working out the details of how to implement the third. For some reason, the voluntary significant reduction of the global population is not approved for discussion.