The project was funded by NASA and the U.S. Department of Energy with additional support from the Purdue Showalter Trust and Indianapolis-based Knauf Insulation. U.S. Sen. Richard Lugar, R-Ind., who is involved in energy policy and recently launched the Lugar Energy Initiative, said: "I congratulate Purdue for this important initiative. As we proceed with the climate change debate in the United States and with international negotiations, it's imperative that we have the best science to monitor emissions and to make it accessible to the public." Simon Ilyushchenko, an engineer at Google, volunteered his time to create the Vulcan layer. Google engineers are allowed to donate 20 percent of their time, or one day of their workweek, to a cause or project of their choice. As he sought information about climate change, Ilyushchenko said it was difficult to find detailed data at the level of an individual's impact and how different locations compare to one another. He became interested in the Vulcan project after it was first released as a tool for the scientific community in April 2007. "Vulcan had great information, but was not easy for a non-scientist to analyze and understand," Ilyushchenko said.

"Integrating the data with Google Earth was a way to advance public understanding of fossil fuel energy usage. Dynamic maps of the data, broken down by the different sources of emissions, easily show where people burn more gasoline from driving or where they use more fuel for heating and cooling homes and businesses." Carbon dioxide is the most important human-produced gas contributing to global climate change, Gurney said. The United States accounts for about 25 percent of the global emissions. The Vulcan layer on Google Earth shows carbon dioxide emissions in metric tons at the state level, county level and per capita. It also breaks down emissions by the different sectors responsible for the emissions, including aircraft, commercial, electricity production, industrial, residential and transport. Peter Griffith, director of NASA's Carbon Cycle and Ecosystems Office and coordinator of the North American Carbon Program, has followed the progress of the Vulcan project. "One of the goals of the U.S. Climate Change Science Program is to assist with scientifically based formulation of policy and decision making," he said.

"By allowing non-specialists to see changes in carbon dioxide emissions in time and across broad areas, we're helping them to understand critical information for climate change policy decisions." Vulcan project data will complement NASA's Orbiting Carbon Observatory, a satellite set to launch later this month that will precisely quantify levels of atmospheric carbon dioxide. Vulcan integrates data including imagery of the Earth's surface captured by the NASA-built Landsat 5 satellite, carbon dioxide emissions data from the U.S. Environmental Protection Agency and U.S. Department of Energy, and population data from the U.S. Census Bureau. The current emissions are based on information from 2002, but the Vulcan system will soon expand to more recent years. Gurney's team would like to fill in information from 1985 to the present and then update the data every six months, he said. "This is the first step," Gurney said. "We'll keep adding more information to enrich it. We hope to eventually get feedback from the public about energy use and activity that allows us to include even more detailed information. This would create a network of businesses and individuals that would become part of the Vulcan system and part of the scientific effort."

Scott Miller, director of sustainability and product affairs at Knauf Insulation, said the Vulcan project helps individuals understand why emissions are higher in some areas than others through examination of the different sectors and how long commutes, older housing and industrial areas come into play. "Vulcan allows consumers to understand their potential impact on climate change and how seemingly small changes could impact the emissions in their area," he said. "For example, buildings represent about 40 percent of our nation's greenhouse gas inventory, and changes such as improved insulation can contribute to a reduction in that inventory." Gurney said the Google Earth content will continually grow as the detail of the data-gathering effort improves. Next the team plans to gather even finer detail with the goal of being able to have emissions data at the street level.

The team also plans to expand Vulcan to other countries, beginning with Canada and Mexico. In addition to the national-level effort, the Purdue team is currently performing a pilot study on the city of Indianapolis, named Hestia after the Greek goddess of the hearth fire, in which carbon dioxide emissions are estimated down to the individual building level. Supported by Knauf Insulation and Purdue's Showalter Trust, Hestia project results are expected to be released by late this year.