Vulcan System Details CO2 Emissions by the Hour

A new, high-resolution, interactive map of U.S. carbon dioxide emissions from fossil fuels has found that the emissions aren't all where we thought.

"For example, we've been attributing too many emissions to the northeastern United States, and it's looking like the southeastern U.S. is a much larger source than we had estimated previously," says Kevin Gurney, an assistant professor of earth and atmospheric science at Purdue University in West Lafayette, Ind., and leader of the project.

The maps and system, called Vulcan, show carbon dioxide emissions at more than 100 times more detail than was available before. Until now, data on carbon dioxide emissions were reported, in the best cases, monthly at the level of an entire state. The Vulcan model examines emissions at local levels on an hourly basis.

Researchers say the maps are more accurate than previous data because they are based on greenhouse gas emissions instead of estimates based on population in areas of the United States.

To create the Vulcan maps, the research team developed a method to extract the carbon dioxide information by transforming data on local air pollution, such as carbon monoxide and nitrous oxide emissions, which are tracked by the U.S. Environmental Protection Agency, the U.S. Department of Energy and other governmental agencies.

"These pollutants are important to determine the ozone levels and air quality in major cities, and they are tracked on an hourly basis," Gurney says. "We've been able to leverage that data to determine the levels of CO2 being produced."

The increased detail and accuracy of Vulcan will help lawmakers create policies to reduce emissions while also increasing scientists' understanding of the sources and fate of carbon dioxide, researchers say.

Gurney says the inventory system, which is named for the Roman god of fire, quantifies all of the carbon dioxide that results from the burning of fossil fuels such as coal and gasoline. It also tracks the hourly outputs at the level of factories, power plants, roadways, neighborhoods and commercial districts.

A preliminary analysis of the Vulcan data suggests that previous maps of U.S. fossil fuel emissions were inadequate for current scientific and policy-making needs, Gurney says.

"When you compare the old inventories to Vulcan, the new data show atmospheric CO2 differences that are as large as five parts per million in some U.S. regions in the late winter," he says. "The levels in the global atmosphere only rise one and a half part per million every year, so this is the equivalent of three years of global emissions in the atmosphere that isn't where we thought it was. This will be important for policy-makers and is enormous from a scientific point of view. It's shocking."

The three-year project, which was funded by National Aeronautics and Space Administration and the U.S. Department of Energy under the North American Carbon Program, involved researchers from Purdue University, Colorado State University, and Lawrence Berkeley National Laboratory.

Vulcan data is available for anyone to download from the Web site at http://www.eas.purdue.edu/carbon/vulcan.

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