Producing a new car releases about 8 tons of carbon dioxide, according to the Sightline Institute. By comparison, burning through a gallon of gas releases about 20 pounds of carbon dioxide, according to the U.S. Environmental Protection Agency.Someone who drives the national average of 15,000 miles a year would generate about 1.5 fewer tons of carbon dioxide by replacing an 18 mpg clunker with a car that gets 22 mpg. That means the 8 tons of carbon dioxide imbedded in the new car would be worked off in about five years.The break-even point comes sooner if the mileage improvement is dramatic. For example, it would take less than a year to recoup the carbon cost of a 46-mpg Toyota Prius replacing a 12-mpg gas hog.
Is that worth what the program costs taxpayers -- $3B now?
If someone keeps this new car for, say, 8 years, and it only saves the carbon of 4 mpg for 3 of these years, then (as the above numbers work out to 20 lb carbon/gallon gas), then they only save 450 gallons for those three years, or only 9000 lbs-C (4.5 tons-C). Thus the whole program (with 245,000 new-car sales) has so far saved 1.1 M tons (imperial tons), or 1.0 MmtC.
In other words, this program is paying about $3000/mtC, a huge amount.
In other words, this is a very poor environmental program and mostly a give away to the middle class, who otherwise complain about pork and government handouts -- except when it benefits them.