NASA: Cars Greatest Net Contributor to Climate Change
Alex Steffen, 22 Feb 10
A new NASA study concludes that cars are the biggest net contributor to climate change:
Cars, buses, and trucks release pollutants and greenhouse gases that promote warming, while emitting few aerosols that counteract it. In contrast, the industrial and power sectors release many of the same gases—with a larger contribution to radiative forcing—but they also emit sulfates and other aerosols that cause cooling by reflecting light and altering clouds...
In their analysis, motor vehicles emerged as the greatest net contributor to atmospheric warming now and in the near term, with a total radiative forcing of 199 mWm-2 in 2020. The researchers found that the burning of household biofuels—primarily wood and animal dung for home heating and cooking—contribute the second most warming. And raising livestock, particularly methane-producing cattle, contribute the third most. The industrial sector releases such a high proportion of sulfates and other cooling aerosols that it actually contributes a significant amount of cooling to the system. And biomass burning—which occurs mainly as a result of tropical forest fires, deforestation, savannah and shrub fires—emits large amounts of organic carbon particles that block solar radiation.
Now, obviously, if we want to slash net emissions to zero in the next few decades, we'll need to eliminate or offset all of our emissions, including the ones that cause comparatively less warming (or "forcing"). Less bad does not mean good.
But this adds more evidence to the idea that our first target, especially in the U.S., should be cars and trucks. And we already know that the way to solve the problem of cars is to build better cities.
You could rewrite the headline here to say, "NASA confirms that bright green cities are essential to climate action."
If the raising of livestock is really the third largest contributer to climate change, then that's another good reason to eat less (or no) meat. Particularly cattle.
Posted by: John G. on 23 Feb 10
Why isn' the airlines whom exhaust a trememdous amount at sky level, not ground level never included??
Posted by: DLM on 24 Feb 10
Another report to make drivers feel guilty, please let me correct it: cars are not ruining the planet, it's their use of fossil fuels that do.
If all cars were running on solar energy, they would be climate neutral. Our goal shall be to make cars able to run on renewables, not to give up motorized individual transport.
Posted by: elji on 25 Feb 10
"If all cars were running on solar energy, they would be climate neutral."
That's an absurd statement.
From manufacturing to road-building to health care costs, cars have massive climate, environmental and social impacts beyond their tailpipe emissions. Even if they ran on fairy dust, cars would have a massive impact on the planet.
And, of course, they mostly run on oil, and will for the foreseeable future.
Posted by: Alex Steffen on 28 Feb 10
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