Gibbs' previous findings asserted that the carbon debt incurred from cutting down a tropical forest could take several centuries or even millennia to repay through carbon savings produced from the resultant biofuels.
On the other hand, planting biofuel croplands on degraded landland that has been previously cultivated but is now providing very low productivity due to salinity, soil erosion, nutrient leaching, etc.could have an overall positive environmental impact, Gibbs said.
"In a sense that would be restoring the land to a higher potential to provide environmental services for people," she added.
Both Brazil and Indonesia contain significant areas of degraded landin Brazil, the total area may be as large as Californiathat could be replanted with crops, thereby decreasing the burden on forested land. "But this is challenging without new policies or economic incentives to encourage establishing crops on these lands," Gibbs said.
This is because farmers who convert degraded land to cropland must shoulder the costs of fertilizer and learn improved soil management practices to make the lands productive, whereas farmers who clear forested land often avoid these burdens.
"Government subsidies, environmental certification schemes or carbon markets could provide incentives to grow crops on degraded rather than forest lands," Gibbs said.
However, in some cases, allowing the degraded land to be returned to its natural, forested state might be the wisest use of the land, absorbing more carbon and providing ecological services such as flood mitigation, rainwater recycling and habitat for endangered species, Gibbs said.
"There are tradeoffs in all these decisions that need to be made on a case-by-case basis," she s
|Contact: Louis Bergeron|