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By Samuel R. Avro on Feb 15, 2009 with no responses

Study: Biofuels May Accelerate, Not Slow, Climate Change

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Tropical forests are the world's most efficient storehouses for carbon, harboring more than 340 billion tons, according to Gibbs' research.

A biofuel boom, which would cause farmers to seek more space to plant crops, can do more harm than good for the environment, says a Stanford University researcher.

“If we run our cars on biofuels produced in the tropics, chances will be good that we are effectively burning rainforests in our gas tanks,” warned Holly Gibbs of Stanford’s Woods Institute for the Environment.

She fears that farmers will raze tropical rainforests in an effort to cash in on the upsurge in demand for biofuels.

An environmental disaster may be “just around the corner without more thoughtful energy policies that consider potential ripple effects on tropical forests,” she added.

Gibbs studied 20 years worth of satellite photographs taken of the tropical regions, and found that 50 percent of new land for growing crops came from intact rainforestes with another 30 percent coming from disturbed rainforests.

“If biofuels are grown in place of forests, we’re actually going to end up emitting a huge amount of carbon. When trees are cut down to make room for new farmland, they are usually burned, sending their stored carbon to the atmosphere as carbon dioxide. That creates what’s called a carbon debt,” Gibbs said. “This is because the carbon lost from deforestation is much greater than the carbon saved from using the current-generation biofuels.”

She hopes that her findings will cause decision-makers to factor in the effects that growing biofuels without a well thought-out plan can have on the environment, and to compensate with new policies.

Gibbs said that high-yield crops like sugar can take up to 120 years to repay the carbon debt. Lower yield crops such as corn and soybeans may take up to 1,500 years.

Tropical forests are the world’s most efficient storehouses for carbon, harboring more than 340 billion tons, according to Gibbs’ research. This is equivalent to more than 40 years worth of global carbon dioxide emissions from burning fossil fuels.

Holly Gibbs wants to see an incentive for farmers to grow their crops on degraded land, instead of using forested land.

On the other hand, planting biofuel croplands on degraded land—land 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.

Both Brazil and Indonesia contain significant areas of degraded land—in Brazil, the total area may be as large as California—that 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,” She said.

She presented her research in Chicago on Saturday, February 14, at the annual meeting of the American Association for the Advancement of Science. The symposium was titled “Biofuels, Tropical Deforestation, and Climate Policy: Key Challenges and Opportunities.”