Vehicles' carbon emissions dip
The rate of CO2 emissions from new U.S. cars and light trucks has dropped for the first time in 20 years, but total emissions have continued to rise since 1990, according to a new report from the advocacy group Environmental Defense.
The authors analyzed CO2 emissions data from the U.S. Department of Energy's Energy Information Administration through 2005, the most recent data that are available. Overall, automobile emissions have risen 73% since 1973. A pattern of increased driving since that time contributed to the increase, as did a drop in average fuel economy since 1988, the authors note. From 2004 to 2005, the average emission rates of new vehicles dropped 3%, a change that the authors attribute in part to tighter fuel economy standards for light trucks.
