Provocative NASA study puts road traffic ahead of power plants as cause of climate change near-term

(Picture of auto traffic from Flickr and photographer Lynac)

A new study from NASA’s Goddard Institute for Space Studies says tailpipe emissions will cause the most global warming over the next decade. Next comes heating homes by burning wood and cow dung in poor countries. Third is methane from cows.

Electric power is further down the list, though it will be the prime source of warming by century’s end, the study predicts. The provocative study, by a team led by NASA’s Nadine Unger, was published this month in the Proceedings of the National Academy of Sciences.

Policy implications
Does this mean we should turn away from fighting the coal industry and focus more on electric cars, high-speed rail and aid to third-world countries? Possibly. We may have a little more time than we thought to shut off coal – as far as global warming is concerned.

But this is just one study. It will need to be confirmed by others.

And the reason behind the findings is troubling. It all has to do with the release of aerosols that block the incoming sunlight and have a temporary cooling effect. Tailpipe emissions don’t have much of those, while coal-fired plants do. Some aerosols, such as sulfates and organic carbon, have a very short-term cooling effect (they are rained down in just a few days), while greenhouse gases stay aloft for decades.

Of course this is a double-edged sword. Aerosols have a known harmful effect on human health and on the environment. That’s why industrialized countries have been phasing them out.

A choice we don’t want to make
Do we have to choose between climate change and our health? Unger says, “no,” that we need to phase out unhealthy aerosols, but that an immediate focus on transportation will give us the biggest bang for our buck in the next decade.

A sound way to proceed is by attacking all sources – tailpipes, burning of wood and dung, cattle-produced methane AND power plants. If we can remove many of the sources of greenhouse gases, we won’t need unhealthy particles in the air to block out the sun.

To read about the study and see graphs go to NASA’s Web site.

See Q&A with Unger. (Caution: Don’t be biased by her picture. She’s a pretty blonde.)

If you want to read the study abstract.

(Sources: NASA, Proceedings of the National Academy of Sciences, fastcompany.com)