Traveling by car increases global temperatures more than by plane, but only in long term

August 4, 2010
Traveling by car contributes to global warming much more than traveling by bus, motorcycle, or train. Credit: iStock

Driving a car increases global temperatures in the long run more than making the same long-distance journey by air according to a new study. However, in the short run travelling by air has a larger adverse climate impact because airplanes strongly affect short-lived warming processes at high altitudes. The study appears in ACS' Environmental Science & Technology.

In the study, Jens Borken-Kleefeld and colleagues compare the impacts on global warming of different means of transport. The researchers use, for the first time, a suite of climate chemistry models to consider the climate effects of all long- and short-lived gases, aerosols and cloud effects, not just , resulting from transport worldwide.

They concluded that in the long run the global temperature increase from a car trip will be on average higher than from a plane of the same distance. However, in the first years after the journey, air travel increases four times more than car travel. Passenger trains and buses cause four to five times less impact than automobile travel for every mile a passenger travels. The findings prove robust despite the scientific uncertainties in understanding the earth's climate system.

"As planes fly at high altitudes, their impact on ozone and clouds is disproportionately high, though short lived. Although the exact magnitude is uncertain, the net effect is a strong, short-term, temperature increase," explains Dr. Jens Borken-Kleefeld, lead author of the study. "Car travel emits more carbon dioxide than air per passenger mile. As carbon dioxide remains in the atmosphere longer than the other gases, cars have a more harmful impact on change in the long term."

Explore further: Faster Climate Change Predicted as Air Quality Improves

More information: "Specific Climate Impact of Passenger and Freight Transport", Environmental Science & Technology.

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3 / 5 (2) Aug 04, 2010
First it needs to be established that CO2 causes global warming.

Despite all the fudging of data and the awarding of Nobel Prizes to Al Gore, the UN's IPCC, and an army of climateologists receiving federal research grant funds, . . .

That fact has not been established!

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
3 / 5 (1) Aug 04, 2010
The usual flaw in these studies is the comparison not of air verses road but of private verses commercial public transport eg it is safer to travel by commercial airliner than a private car but safety is comparable when travelling by private plane and less safe in an ultra-light private plane than a car. At least they acknowledge the train and bus but go on to compare cars with commercial jets anyway.

Likewise it is much safer to travel by bus and even safer by train, but nobody seems to compare trains with jet liners and cars with private planes.

When apples are compared with apples, things become far clearer and the bulk of the difference between road and air travel disappears.

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