A Better Alternative
What would make the petroleum savings significant, according to the Berkeley team, is to produce the ethanol not from corn but from cellulose.
“Ethanol can be, if it’s made the right way with cellulosic technology, a really good fuel for the United States,” said Alex Farrell, assistant professor of energy and resources at Berkeley. “At the moment, cellulosic technology is just too expensive. If that changes – and the technology is developing rapidly – then we might see cellulosic technology enter the commercial market within five years.”
The cellulosic ethanol is made by fermenting the fibrous content of plants, and it can be made from most plant materials including farm waste – though materials such as switchgrass and willow trees work best.
Whether using corn or other plant materials, it is clear that the agricultural world has a significant impact on the environment. Another study (not associated with those reviewed by the Berkeley team) suggests that farmers can reduce greenhouse gases in ways not connected to ethanol.
Climate scientists from the Lawrence Livermore National Laboratory in California say croplands managed with certain techniques can actually lower local temperatures.
“Nearly all models used to predict climate change either ignore agriculture altogether or assume that farmers behave the same way through time,” said David Lobell, lead author of the study’s paper. “In reality, farmers are changing rapidly in response to new technologies, growth in demand, and other factors. This study suggests that these changes may have important cooling effects, especially at local scales.”
Croplands tend to reflect more sunlight than other land covers, which causes the cooling of local temperatures.
In recent decades, farmers have increased the amount of irrigation to crops and tend to plant more than one crop annually in a given field. Also, farmers tend to plow fields less than they used to, which makes the land more reflective.
These findings indicate that the connection between farming and global warming may not be as clear-cut as thought. Before, carbon levels were the main focus of trying to reduce global warming.
“This study illustrates that carbon is not the only important way that agriculture affects climate, and so focusing only on carbon may lead to an under- or over-evaluation of agriculture’s role,” Lobell concluded.
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