Science News reports on Holly Gibbs talk on biofuels and land clearing at AAAS:

Two papers published last year suggested that clearing tropical forests to plant biofuel crops might actually worsen climate change, but that planting biofuels crops on “degraded” land – such as abandoned agricultural land – offers a net benefit to climate.

Gibbs analyzed satellite images taken from 1980 to 2000 to try to answer the question of whether tropical crops are largely being planted on deforested or degraded land. She found that the majority of new crops were planted on freshly deforested rather than degraded land.

Gibbs said she could not tell from her data whether the new crops were planted for food or fuel. But she added, “What we know is that biofuel use is definitely fueling deforestation.” She said when biofuel prices increase, the amount of deforestation increases as well. She said she would personally estimate that between one-third to two-thirds of deforestation over the past couple of years has been due to the planting of biofuel crops.

“If we run our cars on biofuels produced in the tropics, chances are good that we are effectively burning rainforests in our gas tanks,” Gibbs said.