The great New York Yankee baseball catcher, Yogi Berra, had many clever sayings. Among them, “You can observe a lot by just watching!” and “It’s tough to make predictions, especially about the future!” In 2007, the U.S. EPA was given the tough task of predicting Land Use Changes (LUC) due to RFS2 induced corn ethanol demand and predicting soil carbon and soil nitrous oxide emissions when land use changed. But it was required by the RFS2 legislation, so they had no choice.
This requirement spurred others to try their hand at corn ethanol LUC modeling too. In 2008, Timothy Searchinger from Princeton University was one of the first to weigh in. He predicted that producing 15 billion gallons of corn ethanol by 2015 would require an additional 27 million acres of new cropland, and soil carbon losses from those forest and grassland converted to cropland would be a ton and a quarter per acre per year for the next 30 years. This soil organic carbon (SOC) loss rate was about four times faster than many soil scientist measured during the first five decades of the 1900s and resulted in a LUC GHG penalty of 104 grams per megajoule! More than doubling corn ethanol lifecycle GHG emissions! The California Air Resources Board estimated a 30 gram per megajoule penalty in 2009. It took the EPA until 2010 to finish their analysis, and they settled on a 28 gram per megajoule penalty from 21 million acres of forest and grassland conversions that caused soil carbon losses of one-third ton per acre per year. All three of these estimations of LUC GHG penalties meant that corn ethanol lifecycle GHGs were higher than fossil gasoline.
Hundreds of experts testified during the EPA analysis and the common narrative was that RFS2 induced corn ethanol requirements would: 1) significantly increase corn prices, 2) require in excess of 20 million more acres of cropland, 3) significantly reduce corn exports, triggering international land use changes, 4) constrict meat and milk production, 5) inflate food prices, and 6) stagnate, or even drop future U.S. average corn yields because newly converted land is less productive. Environmental group and public support for corn ethanol fuel evaporated overnight.
Baseline of Land Use Change relevant statistics in the five-year period leading up to RFS2:
But as the years went by, it soon became apparent that the extent of forest and grassland conversions had been far overestimated. In fact, there has been little or no change in cropland planted area in the U.S.
Other dire predictions were far off base too. U.S. corn exports did not decline, meat and milk production steadily increased, corn yields have continued to steadily increase, and food price inflation over the five-year period ending in 2018 has been less than half of the five-year period ending in 2007.
A comparison of the two five-year periods:
Old Yogi’s words ring true, “It’s tough to make predictions, especially about the future!”
What happened? How could all those experts be so wrong?
And even now, in spite of all these facts, Lark et al. modeled a 44 gram per megajoule corn ethanol LUC GHG penalty in the spring of 2022.
Yogi would say, “It’s like déjà vu all over again!”
Perhaps the traditional approach to LUC modeling needs refinement?
In October 2022, the International Energy Agency Bioenergy Task Force published a report titled “Towards an Improved Assessment of Indirect Land-Use Change.” This IEA task force argues that the traditional LUC modeling approach in use, described as the “trade and market response narrative,” has failed to accurately predict corn ethanol land use change, and when an alternative modeling approach is used, described as the “internal adjustment response narrative,” a negligible LUC impact is predicted. Very similar to the facts on the ground.
In 1918, Max Planck, the great German Theoretical Physicist, won a Nobel Prize for revolutionizing human understanding of atomic and subatomic processes. He is also famous for postulating “Planck’s Principle.” Planck's principle is the view that scientific change occurs not because individual scientists change their mind, but rather that successive generations of scientists have different views. Planck’s principal is often paraphrased as “science progresses one funeral at a time.”
It is my hope that these International Energy Agency Bioenergy Task Force recommendations are taken seriously and the “trade and market response narrative” LUC modeling approach will be in the morgue soon. The land use impacts of the RFS2 induced corn ethanol build-out is no longer theoretical, we just need to compare the relevant LUC data from pre and post RFS2.
