Global Challenges/Chemistry Solutions

Future Cities: The right choices on transportation can shrink your own personal carbon footprint

January 25, 2011

Cars in traffic
Travelling by car contributes to global warming much more than travelling by bus, motorcycle, or train.
Credit: iStock

Summary

Planes and trains. Cars and trucks. People and
policymakers are measuring almost all kinds of
transportation with a yardstick called global warming.
A study published in the American Chemical
Society’s journal, Environmental Science &
Technology
, offers new insights into how people can
shrink their own personal carbon footprints by
selecting specific modes of transportation. It provides
a comparison of how different means of transportation
impact global warming.

Planes and trains. Cars and trucks. People and policymakers are measuring almost all kinds of transportation with a yardstick called global warming. A study published in the American Chemical Society’s journal, Environmental Science & Technology, offers new insights into how people can shrink their own personal carbon footprints by selecting specific modes of transportation. It provides a comparison of how different means of transportation impact global warming. For the first time, the researchers include the climate effects of all long- and short-lived gases, aerosols and clouds — not just carbon dioxide — from transport worldwide. Their findings? Driving a car increases global temperatures in the long run more than making the same long-distance journey by air. 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. Here is lead scientist Jens Borken-Kleefeld, of the International Institute for Applied Systems Analysis in Austria.

“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. Car travel, on the contrary, emits more carbon dioxide than air travel per passenger mile. And as carbon dioxide remains in the atmosphere longer than the other gases, cars have a more harmful impact on climate change in the long term.”

But the study also noted that passenger trains and buses cause four to five times less impact than automobile travel for every mile a passenger travel. The findings point to a simple prescription for shrinking your carbon footprint: Take public transportation rather than drive.

Smart Chemists/Innovative Thinking

Smart chemists. Innovative thinking. That’s the key to solving global challenges of the 21st Century. Be sure to check our previous Global Challenges podcast episodes by visiting www.acs.org/globalchallenges. Today’s podcast was written by Mark Sampson. I’m Adam Dylewski at the American Chemical Society in Washington, DC.

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Jens Borken-Kleefeld,
International Institute for
Applied Systems Analysis