Scientists plan to map carbon dioxide emissions in Los Angeles and Phoenix. (Arizona State University )
Climate scientists are creating a three-dimensional carbon dioxide emissions map of the city of Los Angeles that will detail greenhouse gas emissions for individual buildings, road segments and power generators over time.
The mapping project is part of an effort by Arizona State University researchers to eventually map all major cities in the United States to help guide climate policymakers.
In a report published Tuesday in the journal Environmental Science & Technology, atmospheric scientist Kevin Gurney and colleagues described how they recently completed a similar map for the city of Indianapolis.
Authors said it was the first such finely detailed account of an urban area and its fossil fuel carbon emissions. Prior maps and analysis have covered larger areas, or have taken a more general approach.
The mapping system, called Hestia, after the Greek goddess of the hearth and home, uses computer modeling, traffic conditions, local air pollution reports, tax assessment records and other public data. Eventually, authors say, the maps will incorporate data from satellites, as well as measurements taken on the ground and by aircraft.
In addition to studying Los Angeles, researchers have also begun work on a map of Phoenix.
"Cities have had little information with which to guide reductions in greenhouse gas emissions -- and you can't reduce what you can't measure," said Gurney, an associate professor at ASU's School of Life Sciences and senior scientist with the Global Institute of Sustainability.
"With Hestia, we can provide cities with a complete, three-dimensional picture of where, when and how carbon dioxide emissions are occuring," he said.
Though carbon dioxide is not the only greenhouse gas, it is the most significant because it remains in the atmosphere for hundreds or thousands of years.
Study authors said their focus on mapping major cities had to do with demographics. Just over 50% of the world's population lived in cities in 2010 and that segment was expected to grow to 68% by 2050.
"These results may also help overcome current barriers to the United States joining an international climate change treaty," Gurney said. "Many countries are unwilling to sign a treaty when greenhouse gas emission reductions cannot be independently verified."