Carbon Dioxide maps zoom in on greenhouse gas sources

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 and leader of the project.

The maps and system, called Vulcan, show CO2 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 CO2 emissions at local levels on an hourly basis.

Researchers say the maps also 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 CO2 information by transforming data on local air pollution, such as carbon monoxide and nitrous oxide emissions, which are tracked by the 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."

Carbon dioxide is the most important human-produced gas contributing to global climate change. The United States accounts for about 25 percent of global CO2 emissions. The increased detail and accuracy of Vulcan will help lawmakers create policies to reduce CO2 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 CO2 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. The three-year project, which was funded by NASA 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.

To extract the CO2 information from the data on other pollutants, research scientists in the Office of Information Technology at Purdue developed a computational system to apply Gurney's methods to existing information. Once the data was converted to determine the CO2 emissions, it was combined with geographic information systems (GIS) data to layer the emissions onto roads and other infrastructure at the Earth's surface. The current emissions are based on information from 2002, but the Vulcan system will soon expand to more recent years.

Vulcan is expected to complement NASA's planned December 2008 launch of the Orbital Carbon Observatory satellite, which will measure the concentration of CO2 in the Earth's atmosphere.

The Vulcan data is available for anyone to download from the Web site at http://www.eas.purdue.edu/carbon/vulcan. Smaller summary data sets that offer a slice of the data and are easier to download also are available for non-scientists on the Vulcan Web site. These can be broken down into emission categories, such as industrial, residential, transportation, power producers, by fuel type, and are available by state, county, or cells as small as six miles (10 kilometers) across.

A video of the maps and simulations of the atmospheric fate of fossil fuel CO2 also can be viewed on YouTube at http://www.youtube.com/watch?v=eJpj8UUMTaI.

Source : http://www.eurekalert.org/