Researchers define challenging carbon-emissions targets for U.S. auto industry

Jan 28, 2009

(PhysOrg.com) -- U.S. automakers must achieve an eightfold reduction in automobile-related carbon emissions to help stabilize the amount of heat-trapping carbon dioxide gas in the atmosphere by 2050, according to University of Michigan researchers.

A research team from the U-M Center for Sustainable Systems looked at what it would take for U.S. automakers to reduce passenger car-related carbon emissions to help stabilize carbon dioxide levels at a concentration of 450 parts per million by 2050, thereby averting many of the most serious consequences of human-caused climate change.

Currently, U.S. passenger vehicles emit about 160 grams of carbon for every mile driven, when tailpipe emissions and emissions associated with fuel production are included. To help stabilize emissions by 2050, that number must be reduce eightfold, to 20 grams per mile, according to center co-director Greg Keoleian of the U-M School of Natural Resources and Environment.

The U-M study appears in the Feb. 1 edition of the journal Environmental Science & Technology, an American Chemical Society publication. Keoleian said the study is the first to define specific targets needed to achieve sustainable U.S. passenger-vehicle transportation.

Reaching those carbon-reductions targets will require an aggressive combination of strategies, according to Keoleian and his co-authors, Hilary Grimes-Casey and Blair Willcox of the Center for Sustainable Systems.

Improving vehicle fuel efficiency, the widespread use of low-carbon fuel, and a change in U.S. driving habits have all been suggested as ways to reduce carbon emissions. But no single approach will suffice, Keoleian said.

Attempting to reach the emissions-reduction targets by adopting just one of these approaches would require: automobiles with an average fuel economy of 136 miles per gallon, an 83 percent market share for low-carbon ethanol, or a reduction in U.S. travel demand of 53 percent by 2050, according to computer-model simulations conducted by the U-M researchers.

"Any individual vehicle carbon-reduction strategy is not likely to be successful in the long term," Keoleian said. "To meet these targets, we need a combination approach that tackles all these factors simultaneously.

"Most importantly, we need a transformed energy system," he said. "Basically, we have to shift our emphasis on fossil-based fuels to renewable and, in the interim, there might be more of a role for nuclear. At the same time, we need to dramatically ramp up our fuel economy and reign in vehicle miles traveled."

In the United States, transportation accounts for about a third of all greenhouse-gas emissions, and automobiles are responsible for two-thirds of transportation-sector emissions.

Several automobile manufacturers have announced plans to build plug-in hybrid cars that can recharge at the nearest wall socket. Clearly, vehicles powered mainly by batteries produce fewer emissions than cars that rely solely on internal-combustion engines.

But if the wall-outlet electricity is generated at a coal-fired power plant, then plug-in hybrids merely shift a portion of the carbon emissions from the vehicle to the power plant. Achieving significant overall reductions in transportation-related carbon emissions will require big reductions in the use of fossil fuels for power generation, as well as for liquid vehicle fuels.

That means an increased reliance on wind, solar and other renewable energy sources, as well as nuclear power.

"If we don't transform our system for generating electricity, the plug-in hybrid electric vehicle will result in some reduction in emissions, but it's not going to be at the level which is needed to solve this problem," Keoleian said.

Provided by University of Michigan

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User comments : 13

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GrayMouser
2.6 / 5 (5) Jan 28, 2009
How about we set the limits to the maximum natural CO2 levels see historically?

You know, somewhere around 5000ppm to 10000ppm?
DGBEACH
2.3 / 5 (3) Jan 29, 2009
How will the population be able to BUY these vehicles during a prolonged depression? It would be easier and probably cheaper just to GIVE each American family an electric car in exchange for their old polluting ones.

The old ones could then be recycled, and the metal used for the newer ones!
MikeB
3 / 5 (4) Jan 29, 2009
Yeah!!! Where's my free car?!?
theophys
3 / 5 (3) Jan 30, 2009
I believe it was actauly proposed to have a credit sytem for those who want to exchange their old cars for newer, greener ones. Personally, I think we could use all the old Hummers in the military. Build a really big trebuchet and start launching the most useless civilian vehicle of all time at suspected terrorists. That'll send a message.
OdinsAcolyte
3.4 / 5 (5) Jan 30, 2009
I think we can significantly reduce noxious gases by ending the fraudulent carbon trade off program and stuffing a sock in the mouths of the politicians and semi-scientists who promote this heat scam agenda. Almost nobody believes it now. Folks are a lot wiser than they bargained for. We need to put the UN in a future balmy spot like the Siberian tundra and let them wait for the heat to hit.
MikeB
3 / 5 (4) Jan 30, 2009
Gore and Pachauri, and anyone else that is preaching the catastrophic catechism, remind me of kidnappers. You better bring the money, don't call the cops, or something very, very bad will happen to you and yours. Do it for your child... or else.

Does anyone else feel like our world is being held for ransom?
GrayMouser
3 / 5 (4) Jan 30, 2009
I believe it was actually proposed to have a credit system for those who want to exchange their old cars for newer, greener ones.

And the the ecological/carbon footprint of making those new cars? How is that accounted for against keeping the preexisting cars which now only have the footprint of their current existence?
Velanarris
3 / 5 (4) Jan 31, 2009
I believe it was actually proposed to have a credit system for those who want to exchange their old cars for newer, greener ones.

And the the ecological/carbon footprint of making those new cars? How is that accounted for against keeping the preexisting cars which now only have the footprint of their current existence?
This is especially relevant as the materials needed for plug in hybrids are rare earth metals typically found deep within mountain.

People complain enough about coal mining, you have no idea what palladium mining does to the environment. It's far more catastrophic for far fewer materials.

Materials that are not recyclable, highly toxic, (unlike CO2), and incredibly expensive to produce.
Noein
2.6 / 5 (5) Jan 31, 2009
"There's an infinite supply of coal, oil, and natural gas, and burning them doesn't have any effect on the environment at all, so there's no need to worry about anything. Just keep doing what you're doing, good citizens of America. Keep gobbling up that oil like good little piggies."

This message brought to you in part by a grant from Exxon.

Exxon -- clinging to yesterday's technology today
Noein
2 / 5 (4) Jan 31, 2009
People complain enough about coal mining, you have no idea what palladium mining does to the environment. It's far more catastrophic for far fewer materials.


Coal is clean and very nutritious. Coal bread, coal mashed potatoes, coal gravy...the culinary possibilities are endless! King coal has lots of excellent recipe ideas for using coal in everyday American dishes over at his website:

http://www.coalisclean.com
Velanarris
5 / 5 (2) Feb 02, 2009
Noein, I fail to see the relevance of your anti-coal tirade.
MikeB
5 / 5 (1) Feb 02, 2009
Coal lay in ledges under the ground since the Flood, until a laborer with pick and windlass brings it to the surface. We may will call it black diamonds. Every basket is power and civilization. For coal is a portable climate. ~Ralph Waldo Emerson
Who knew that Ralph was such a reprobate...
Emerson... come to Noein... he will bring you into the beautiful light of knowledge...
Micilin
not rated yet May 01, 2009
How about we figure out how to get there from here without bankrupting all of us. Academia produces targets but provides no operations management processes to attain those objectives. The government itself is not only on the verge of bankruptcy, it is one of the largest sources of pollution in the world.

For starters, the government should form its own energy cartel to compete with OPEC and completely eliminate our dependence on foreign oil and remove much of the flow of capital that currently funds militant Muslim conflicts all over the globe. It should not nationalize the oil companies but rather sell oil to them as OPEC does now. The revenues from such operations could be used to eliminate much of our debt and fund transportation and power generation projects that will produce measurable reductions in CO2 while creating a sustainable economy for future generations.