Running on empty

"If two scientists at Los Alamos National Laboratory are correct, people will still be driving gasoline-powered cars 50 years from now, churning out heat-trapping carbon dioxide into the atmosphere — and yet that carbon dioxide will not contribute to global warming.

The scientists, F. Jeffrey Martin and William L. Kubic Jr., are proposing a concept, which they have patriotically named Green Freedom, for removing carbon dioxide from the air and turning it back into gasoline.

The idea is simple. Air would be blown over a liquid solution of potassium carbonate, which would absorb the carbon dioxide. The carbon dioxide would then be extracted and subjected to chemical reactions that would turn it into fuel: methanol, gasoline or jet fuel.

There is, however, a major caveat that explains why no one has built a carbon-dioxide-to-gasoline factory: it requires a great deal of energy."