How to Halve U.S. Transport Emissions by 2050

ARLINGTON, Virginia, May 29, 2003 (ENS) - By using a set of existing technologies and policies and building on them, it is possible to reduce U.S. carbon emissions from transportation 20 percent by 2015, and almost 50 percent by 2030, says a new report by the Pew Center on Global Climate Change.

Noting that transportation sources account for nearly a third of U.S. greenhouse gas emissions, the report, released today, says it is critical that U.S. climate change policy address transportation emissions. It identifies a number of policies and technologies that could achieve those goals.

"The U.S. is the owner of the world's largest transportation system, and reducing emissions from this system is critical to an effective greenhouse gas reduction strategy," said Eileen Claussen, president of the Pew Center on Global Climate Change. traffic

Traffic in midtown Manhattan (Photo by Ian Britton courtesy FreeFoto)
The report, "Reducing Greenhouse Gas Emissions From U.S. Transportation," written by David Greene of Oak Ridge National Laboratory and Andreas Schafer of the Massachusetts Institute of Technology, stresses that while policy options are available today, the long lead time needed to turn over the nation's vehicles dictates that policies for the future must be implemented now.

"I think the most important thing coming out of the study is that these things can be done by a combination of practical measures which we believe are conservative and that we know can be done without any serious negative impacts on transportation," Greene told ENS. "Some will be beneficial, some will marginally increase costs, some won't change the costs at all. They all have minor impacts on the transportation system."

The U.S. transportation system is the most mobile in the world and is a fundamental part of the health of the U.S. economy and its continued growth, the study says.

It is also the source of one fourth of the world's greenhouse gas emissions, spewing more CO2 than any other nation except China. Transportation accounts for seven of every 10 barrels of oil consumed in the United States.

"By attacking the problem from a variety of different aspects, you can almost cut greenhouse gas emissions in half," Greene said. "We think that's extremely significant. 'Transportation is too hard,' people say. We're saying that you can accomplish quite a bit. These are not drastic things. But you can't do with just one silver bullet." traffic

Traffic near Denver, Colorado (Photo courtesy NREL)
Many of the actions that would reduce emissions from transportation would also lower U.S. dependence on imported oil, the authors say.

Research and development and voluntary efforts will not be enough to do the job, they note. Mandatory policies will be necessary to introduce technological improvements into the marketplace.

Fuel cells and hydrogen hold out the promise of eliminating greenhouse gas emissions from this sector, the report says, but government must provide "clear policy direction in order to drive massive private investment by the fuel and vehicle industries."

The authors drew on existing literature for their conclusions. Their findings about light duty vehicles, for instance, came from a 2002 National Academy of Sciences study on the effectiveness and impact of Corporate Average Fuel Economy standards which found that light duty vehicles account for 75 percent of highway energy use and their total carbon emissions are now comparable to major industrialized countries like Germany and Japan.

But market ready technologies are currently available that will allow fuel economy on new cars and light trucks to be increased by 25 to 33 percent over the next-to 15 years without reducing the size or performance of the vehicles.

"We are adopting technologies capable of improving fuel economy standards, but we're using them to increase horsepower and the size and weight of trucks," Greene said. "Our study assumes no increase in their horsepower weight ratio, but no decline either.

Greene said that the current administration has made some moves in the right direction. The Congressional ban on the National Highway Traffic Safety Association (NHTSA) study of the issue of raising fuel economy standards has been lifted. And the NHTSA has proposed raising fuel economy standards by 1.5 miles per gallon.

"That sounds like a small amount, but you can't raise it that quickly anyway, so it's not as puny as it sounds," Greene said. "The question is whether they will go beyond that. That remains to be seen."

If global mobility is to continue to expand, especially in the developing world, a transition to other sources of energy must begin soon, the report states. "Decisions made in the next several years could determine whether the world's transportation systems follow a path of continued reliance on high carbon fossil fuels or take an alternative path toward more diverse, low carbon energy sources." fuel cell

The vehicle of the future may have a fuel cell using a microchannel fuel processor under the hood. Pacific Northwest National Laboratory has developed a fuel processor for this application. (Photo courtesy PNL )
The report notes that U.S. petroleum consumption decreased from 1973 to 1985, reversing the growth of U.S. petroleum demand. This was accomplished through a combination of increasing fuel economy, other energy efficiency improvements and the substitution of other fuels for petroleum outside the transportation sector.

This decrease proves it is possible to dramatically reduce dependence on outside oil, the report says, and a renewed effort in that direction would have many other benefits. Besides curbing greenhouse gases, it would reduce oil price volatility and strengthen the country's energy security.

"Some of the car manufacturers would like to do something about greenhouse gas, but they don't like fuel economy standards," Greene said. "What our study says is that if you don't, here are some other policies that will also work. Find something you can live with."

Greenhouse gas emissions consequences are now unaccounted for in public as well as private transportation decisions, the report states. "Taking climate change into account in these decisions would provide a major impetus to improve vehicle efficiency, substitute low carbon fuels, and increase transportation system efficiency."

By tackling a broad range of issues, Greene expects some report suggestions to be controversial. "What is really required is that the nation decides it wants to do something about climate change," he said. "There's not a hue and cry today to do something about it. That suggests that it may be a while. It may take more explaining about what it's all about."

To read the entire report, go to: