Addressing carbon on land is essential for stabilizing greenhouse gas concentrations

Pacific Northwest National Laboratory: Putting a price tag on carbon dioxide emitted by different land use practices could dramatically change the way that land is used - forests become increasingly valuable for storing carbon and overall carbon emissions reductions become cheaper, according to research presented today at the annual meeting of the American Association for the Advancement of Science.

"Without valuing the carbon in land, we risk losing large swaths of unmanaged ecosystems to agricultural crops and biofuels," said speaker Leon Clarke of the Joint Global Change Research Institute in College Park, Md., a collaboration between the Department of Energy's Pacific Northwest National Laboratory in Richland, Wash., and the University of Maryland.

Most analyses of future global carbon dioxide output mainly consider carbon emissions from fossil fuels and industrial processes, or otherwise include only parts of the global carbon cycle. This could lead to dramatic changes in how people use land as they cut down trees to grow food and bioenergy crops, according to some studies. This study is the first to value carbon in all natural and human systems.

The scientists found that addressing the land-based carbon is essential for stabilizing greenhouse gases at low levels. Overall, land contains 2,000 billion tons of carbon, compared to the 750 billion tons in the atmosphere. In addition, forests hold more carbon than grazing does. Converting land from forest to food or bioenergy crops releases carbon into the atmosphere. Conversely, turning agricultural land back into forests tucks carbon away on land, reducing it in the atmosphere…..