Time to replace corn with trees.
By Tom Evslin
From his Nov. 11 column Fractals of Change
40% of US corn is used to produce ethanol. According to numbers from the US Department of Energy, substituting a gallon of ethanol for a gallon of gasoline avoids an average of a little over 6 lbs. of “net” CO2 emissions. The fossil fuel needed to grow, transport, and distill the corn is counted; but the CO2 which comes from the burning ethanol is ignored since it was recently captured by the corn – that’s why we call these “net” emissions. Using these calculations, an acre grows enough corn to save 1.38 metric tons of CO2 annually.
However, an acre of Midwest farmland planted in trees removes about 3.5 metric tons from the atmosphere each year. The trees are 250% more effective at CO2 reduction than corn!
From an environmental point of view, it would be a huge gain if all the ethanol-producing acres were turned into forests. 39 million acres of trees would remove 136MMTCO2 (million metric tons of CO2) annually from the atmosphere, 82MMTCO2 more than would be saved if all that corn were turned into ethanol. The trees will keep sequestering CO2 virtually forever. The ethanol only helps so long as there is gasoline use for it to replace. It doesn’t do anything for cars parked while their owners work at home or for electric cars.
From an economic point of view, with ethanol prices below the cost of production, the farmers and refiners are in an unsustainable business. They were lured into producing ethanol by government mandates requiring at least 10% ethanol in most gasoline even though ethanol is more expensive to produce than the gasoline it replaces on a cents per mile basis. The Farm Bureau says “A Pull Back in Corn Acres Is Needed”. They explain that ethanol demand, which had already flatlined before the pandemic, is now in steep decline because Americans are driving less. Prices for ethanol are well below the cost of production. Ethanol refineries are shutting down; farmers are worried that they’ll have nowhere to sell their crop.
From a political point of view, there are three and a half years until Iowa has its next first-in-the-nation primary. The incoming Biden administration has promised to do significant green things without pinning itself down on specifics.
For environmental, economic, and political reasons, now is a very good time to start growing trees instead of corn (stalk2stem) in much of the Midwest. Obviously ethanol production isn’t going to stop all at once and there will be other uses beside growing trees for the land which will no longer be growing corn. Step one, however, is to end all further ethanol subsidies and start phasing out the ethanol mandate; we don’t want to mindlessly expand an already failing program.
There will be a net loss of farm and refinery jobs; trees require a lot less care than corn. But these jobs are doomed as the demand for ethanol continues to decline; an orderly transition to other crops is necessary. National and state programs to buy farmland and turn it into productive forests is as necessary for Midwest corn growers as it is for Vermont dairy farmers. The stalk2stem program can at least partially be financed by ending subsidies for further ethanol development. Growing trees is one of the cheapest ways of reducing greenhouse gasses (GHG). The wood products industry will grow with a new supply of high-grade lumber and wood can increasingly replace concrete structurally for additional GHG savings.
I look forward to hiking the Iowa woods.
According to a study by the Argonne National Lab quoted by the US Dept of Energy, there is an average 34% reduction in GHG when ethanol is substituted for gasoline. These are lifecycle numbers and take into account the energy which goes into growing the corn and refining it. Gasoline emits 19.4 lbs. of CO2 per gallon so substituting a gallon of ethanol for a gallon of gas saves a little over 6 lbs. of CO2. On average, each acre of corn turns into 462 gallons of ethanol annually. CO2 savings from an acre of corn is 3047 lbs. or about 1.38 metric tons per acre per year. According to the University of Minnesota, an acre of Midwest forest sequesters about 3.5 metric tons/year. The rest is just math.
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