|Average global warming and smog scores of MY 2005 vehicles. Click to enlarge.|
The Union of Concerned Scientists (UCS) has released its biennial ranking of the greenest automakers, based on the average emissions of global warming (grams CO2-equivalent per mile) and smog-forming (grams NOx and NMOG per mile) pollutants from vehicles actually sold. For the fourth time in a row, Honda topped the organization’s rankings as the country’s greenest automaker.
Using government data, report author Don MacKenzie analyzed the performance of 10 classes of vehicles produced by the eight automakers which together represent 96% of the US car and light truck market for model year 2005—the latest year for which final data are available.
|Combined scores of the top six automakers since 1998. A higher score is worse. Click to enlarge.|
Toyota lost by only a nose, surging to second place by making significant cuts in global warming pollution, while Honda’s score, in turn, worsened compared to its 2003 performance. Only GM and Toyota saw their results improve from MY 2003 to MY 2005; the other automakers all experienced a worsening of their environmental scores. (Chart at right.)
Hyundai-Kia, Nissan and Volkswagen were in the middle of the pack, coming in third, fourth and fifth, respectively. Ford and General Motors, meanwhile, were at the back, and DaimlerChrysler placed last, earning the Rusty Tailpipe Award for the dirtiest automaker.
There is a huge gap between the cleanest and dirtiest automakers. The winners are using clean technology across their entire fleets. The losers are installing it piecemeal, or not at all.—Don MacKenzie, author of the report and a vehicles engineer with UCS
MacKenzie rated each automaker on how its vehicles compared to the industry average on global warming and smog-forming pollution. Cars and light trucks account for 25% of the nation’s global warming pollution and 20% of its smog-forming pollution.
Honda and Toyota had better-than-average global warming scores in every class in which they competed. Despite producing pickup trucks and large SUVs, Toyota’s use of emissions-cutting technology across its entire fleet helped it to pull up just behind Honda, which did not compete in these vehicle classes.
Toyota’s ranking shows that size is no excuse for a dirty fleet. All of the automakers have the technology today to make all of their vehicles, from two-seaters to four-by-fours, a lot cleaner. And given the Supreme Court ruling confirming carbon dioxide and other global warming emissions are pollutants, it’s likely that federal or state efforts will succeed in requiring automakers to put that technology to work.—Don MacKenzie
Ford was the cleanest of the Detroit automakers, finishing sixth. But if Ford had made the same progress cutting global warming pollution in its US fleet as it has with its European fleet, it would have finished in fifth.
GM, which placed last in UCS’ 2003 model rankings, moved past DaimlerChrysler by reducing its fleet’s smog-forming emissions. But the country’s largest automaker failed to improve its global warming pollution score since the last UCS automaker rankings. In model year 2005, GM sold the most vehicles rated at 15 mpg or worse in city driving.
DaimlerChrysler came in dead last with the worst scores for both smog and global warming pollution. Its cars and trucks emit 70% more smog-forming pollutants and nearly 30% more global warming pollutants per mile than those made by Honda.
The UCS analysis showed hybrids helped improve environmental performance while diesels generally held automakers back. Volkswagen’s diesel engines, for example, slightly improved its global warming score, but significantly dragged down its smog score. Hybrids, meanwhile, helped Toyota cut its global warming pollution fleetwide because the company produced them in large numbers. Honda and Ford, which produced fewer hybrids, did not see the same improvement.
The report also evaluated the impact of flex-fuel vehicles by calculating global warming emission averages for various levels of E85 usage: 2% (somewhat higher than actual usage), 50% (the level assumed by the government in the assignment of CAFE credits), and 100% (the maximum possible). The report concluded that flexible-fuel vehicles (FFVs) are currently doing more harm that good, as the increase in global warming pollution due to the fuel economy loophole for FFVs more than outweighs the theoretical savings due to alternative fuel usage.
The E85 currently available provides only a 16 percent reduction in global warming emissions compared with the gasoline it replaces, but automakers receive a 65 percent bonus on the credited fuel economy of FFVs. As a result, even if FFVs used E85 100 percent of the time, this would still not compensate for the fuel economy loophole. Manufacturers would do much more to reduce global warming emissions if they satisfied fuel economy standards by selling more efficient vehicles, rather than exploiting the dual-fuel loophole. In fact, if Nissan had actually produced a fleet of vehicles as efficient as it was given credit for, its global warming score would have been good enough to put it ahead of Hyundai-Kia in combined scores, into third place overall.