FUKUOKA, Japan — Old cars have a poor reputation for being “gas guzzlers” which just make global warming worse. However, a surprising new study reveals trading in your old car for a brand new electric vehicle may actually be doing more harm than good. Researchers in Japan say choosing to keep and drive your older gasoline-powered car longer leads to fewer emissions entering the environment.
A team from Kyushu University says most of the debate over gasoline and electric cars focuses on fuel efficiency and the CO2 emissions they produce. While electricity and hydrogen are cleaner energy sources, the study finds it still takes a lot of energy to build these vehicles. Specifically, researchers find keeping older fuel efficient cars on the road longer reduces CO2 emissions significantly more than speeding up the global transition to green technology.
“The faster you replace a car, the more CO2 it emits. It’s no different with electric cars, because when the demand for new cars increases, it shoots up manufacturing emissions,” says Shigemi Kagawa, a professor in Kyushu University’s Faculty of Economics, in a university release.
A car’s life is way too short
In Japan, car production and replacement is a staggeringly rapid process. Researchers find the average life of a car, from the production plant to the scrapyard, is just 13 years. Moreover, brand new cars only stay with their first owner for seven years.
This rapid turnover means factories are constantly pumping out more harmful emissions as more and more cars (even electric ones) roll off the assembly line. The team adds that, in Japan, the nation’s mass-consumption economy and costly vehicle inspection system also contribute to this environmental dilemma.
“The carbon footprint of a car goes far beyond just the fuel it uses. To produce alternative fuel cars intended to reduce emissions from driving, you need iron, nuts, and bolts for construction, factories for assembly, and mega-containerships for transport. All these points in the supply chain produce CO2.”
When looking at Japan’s greenhouse gas production, cars contribute to about nine percent of total emissions — with 40 percent of this amount due to gasoline combustion from driving new cars and 24 percent coming from the manufacturing process of these vehicles.
“Our hypothesis is that driving current internal combustion engine vehicles a little longer during the transition to green vehicles is a viable strategy to help the environment,” Kagawa explains.
How long should you keep your car?
The team used economic statistics to examine Japan’s population of both newly registered and used cars between 1990 and 2016. The data allowed them to model how “replacement behavior” impacts the nation’s carbon footprint.
The results reveal that if car owners keep their vehicles on the road 10 percent longer before sending them to the scrapyard, the overall carbon footprint of cars would decrease by 30.7 million tons. That’s the equivalent of a one-percent decrease in CO2 emissions. Researchers say the reason of this is manufacturing new vehicles actually produces more greenhouse gases than continuing to drive existing cars — even if they use gasoline.
The environment would also see a benefit if owners of brand new cars kept their vehicles longer before trading them in. Study authors say there would be a one-percent drop in carbon footprint if new car owners hold on to their rides 10 percent longer.
“What this means is that we can reduce CO2 emissions just by keeping and driving cars longer,” Kagawa concludes. “Moreover, if the car we keep is relatively new and fuel-efficient, the effect is greater. So the next time you are thinking of getting a new car, perhaps consider if your current car has a few more kilometers left in it.”
The study appears in the Journal of Industrial Ecology.