I was disappointed to read Dan Murphy’s article Meat of the Matter: Are we burned out on ethanol? I understand that there are lots of reasons one may support or oppose bioethanol production, but Murphy does agriculture a disservice by perpetuating misinformation on agriculturally derived greenhouse gas emissions (GHG’s). The conclusions of the so-called “highly regarded” report referenced by Murphy, which claims corn grain ethanol actually increases GHG’s relative to gasoline, have been repeatedly and soundly refuted. I suggest the author read the review article published by Kim et al., in Bioenergy Research 2014, that summarized 21 life cycle assessment studies on corn production greenhouse gas emissions in the U.S. Not surprisingly, the study found a wide range of corn production systems ranging from GHG emitters to corn production systems that sequester carbon and reduce atmospheric GHG’s.
In sum, if corn is grown using current best management practices such as conservation tillage, and judicious fertilizer use, corn grain bioethanol is far superior to gasoline in terms of GHG emissions. The misinformation situation is the exact same problem faced by us livestock producers – when manure is managed correctly and rations are right, beef production can be environmentally protective. Nonetheless, the media will usually focus on worst-case livestock production scenarios and extrapolate the consequences to include all animal agriculture.
With bioethanol GHG’s, it’s not complicated – your engine’s GHG emissions from burning corn grain ethanol are simply a recycling of photosynthetically derived carbon that was already in the atmosphere several months to a year previous. Conversely, emissions from fossil fuels like gasoline or diesel constitute the release of additional carbon to the atmosphere, carbon that has been buried deep in the earth for an average of 300 million years, the average age of crude oil carbon. Fossil fuel emissions result in 19 lbs of carbon dioxide released for each gallon of gasoline burned which collectively sums to 2.7 trillion tons of additional carbon pumped into the atmosphere annually.
Today’s farmers use five gallons of gasoline per acre to produce over 500 gallons of ethanol, not to mention an additional ton and a half of DDG’s. In addition, the newly emerging cellulosic-based ethanol from feedstocks such as corn stover or perennial grasses like switchgrass, have an even better GHG potential. Agriculture has a positive story to tell regarding GHG’s. Let’s not lower ourselves by reverting to the misinformation tactics and sensationalism employed by agriculture’s detractors.
Kurt D. Thelen