Wall Street Journal – February 8, 2008
This is a different twist over what I usually propose. In general, I am for increasing our use of ethanol and other biofuels to reduce our CO2 production as well as to reduce our reliance on fossil fuels from the Middle East. Most people are aware that one of the downsides to this issue is the pressure on food that results. This article points out that the conversion of non-agrarian land to crop land will result in a net spike of increased carbon dioxide release.
What the study doesn’t seem to discover is how much of this trend has already happened. As you drive across farm country, you will usually see stands of old woods interspersed within the farms that have been there for many decades (perhaps centuries). I have no data to point to except for observations as I travel in the Midwest, but it does not appear that a great number of these wooded areas are being cut down. My guess is that the expense from this effort offsets the profit that an already financially strapped farmer would enjoy.
The study also doesn’t point out the large amount of land that lies fallow. While this farming technique is not as popular as it once was, it appears to be far more popular in countries outside of the US. According to the 2002 census, almost 18% of the farm land in the US is idle.
A study published in the latest issue of Science finds that corn-based ethanol, a type of biofuel pushed heavily in the U.S., will nearly double the output of greenhouse-gas emissions instead of reducing them by about one-fifth by some estimates. A separate paper in Science concludes that clearing native habitats to grow crops for biofuel generally will lead to more carbon emissions.
The Energy Department expects U.S. ethanol production to reach about 7.5 billion gallons this year from 3.9 billion in 2005, encouraged by high prices and government support. The European Union has proposed that 10% of all fuel used in transportation should come from biofuels by 2020.
Land-use changes can have big and unintended consequences, such as food shortages and reduced biodiversity. For example, when forests or grasslands are converted for agricultural use, it leads to a large, quick release of carbon when the existing plant life is destroyed and the soil is tilled. Even if biofuels are grown on cropland previously used to grow food, farmers tend to then clear other forests and grasslands and grow the food elsewhere.
For example, an increasing amount of land in Brazil is being used to grow sugarcane for ethanol. Converting the undeveloped land into sugarcane fields releases CO2. It would take 17 years for the positive effect of using sugarcane ethanol from those fields instead of petroleum-based fuels to overcome the CO2 farming the land put into the air. Draining and clearing peatlands in Malaysia and Indonesia to grow palm oil emits so much CO2 that palm biodiesel from those fields would have to be burned for more than 420 years to counteract it.
You can read the entire article here.
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Filed under: Greenhouse gas