A new study has looked at how converting land to grow biofuel crops impacts greenhouse gas emissions. Researchers at the DOE Argonne National Laboratory found that in the past analyses only looked at the changes in the amount of carbon stored in the soil and vegetation of these converted lands that were previously forests, grasslands or pastureland.

Argonne environmental analyst Hao Cai, environmental scientist Jiali Wang and climate scientist Yan Feng observe a U.S. map that plots the albedo effects observed across various agro-ecological zones. (Image by Wes Agresta/Argonne National Laboratory.)

So the research team studied the reflectivity effects of converting land, or the “albedo,” which is the amount of incoming solar energy that gets reflected back into space. These changes, combined with other factors, then contribute to climate changes in GHG emissions according to the researchers. The study was published in the The Royal Chemistry Society’s Energy & Environmental Science.

The results of the study show that when a piece of land is changed to produce a biofuel crop, albedo effects changed as well. When looking at only albedo change effects, the team found that land converted to producing corn ethanol had a net cooling effect on the climate. However, when the land was converted to grow several next generation biofuels including miscanthus and swithgrass, the albedo showed a warming effect. However, when the researches looked at carbon stock changes (another factor in climate change) in addition to albedo, corn and switchgrass ethanol showed net warming effects associated with land use change while miscanthus grass ethanol exhibits a net cooling effect.

The work outlines the importance of considering changes in reflectivity when assessing land use change-induced effects of biofuel production on climate. “Our analysis is helping build a fuller picture of the climate effects of biofuel feedstock production,” said Hao Cai, an Argonne environmental analyst and lead author of the study.