Diesel cars may promote more global warming than gasoline cars

More auto news. A Stanford researcher has found that although diesel cars obtain 25 to 35 percent better mileage and emit less carbon dioxide than similar gasoline cars, they can emit 25 to 400 times more soot per kilometer. The warming due to soot may more than offset the cooling due to reduced carbon dioxide emissions over several decades. Laws that favor diesel cars over standard gasoline, therefore, may be doing more harm than good.