STORY AT-A-GLANCE
- Carbon neutrality refers to a product that has net zero carbon emissions. The manufacture and use of corn-based ethanol has expanded based on the assumption that it’s carbon neutral and therefore far better for the environment than gasoline. However, several studies have shown that such assumptions are categorically false
- A 2016 study found corn grown for ethanol only offset 37% of carbon dioxide emissions produced by burning biofuels, resulting in net-positive carbon dioxide emissions that are greater than gasoline
- One of the primary reasons why growing corn for ethanol has a net-positive CO2 impact is because farmers are plowing up native grasslands to make more room for corn; 60 tons of carbon dioxide are released into the environment per acre of grassland plowed
- Ignoring water consumption further underestimates CO2 emissions from land-use change by 28%. When corn plants’ water needs are considered, corn ethanol is worse for the environment than gasoline
- A five-year study published in 2022 concluded the CO2 emissions from corn-based ethanol are at least 24% greater than that of gasoline. On top of that, it has led to increased fertilizer use, resulting in greater water pollution and a growing dead zone in the Gulf of Mexico
Carbon neutrality is the holy grail of the biofuel industry. It refers to a product that has net zero carbon emissions. In the case of ethanol, the corn or soybeans grown to produce it would have to remove as much carbon dioxide from the environment as is given off when the ethanol is burned.
The manufacture and use of ethanol in the U.S. has been allowed to expand based on the assumption that it’s carbon neutral and therefore far better for the environment than gasoline. However, a 2016 study1 by professor John DeCicco, Ph.D., at the University of Michigan, showed that such assumptions were categorically false.
Ethanol Is Far From Carbon Neutral
What DeCicco and his team discovered was that biofuels such as corn ethanol are associated with a net increase in carbon dioxide emissions — even more so than gasoline. It turns out that the crops only offset 37% of carbon dioxide emissions produced by burning biofuels. At the time, DeCicco explained:2
“The name of the game is to speed up how much CO2 [carbon dioxide] you remove from the air … The best way to begin removing more CO2 from the air is to grow more trees and leave them. Prior to settlement, Michigan was heavily forested.
A state like Michigan could do much more to balance out the tailpipe emissions of CO2 by reforesting than by repurposing the corn and soybeans grown in the state into biofuels. That is just a kind of shell game that’s not working.”
Granted, DeCicco’s study was funded by the American Petroleum Institute, which obviously has reason to want to discredit the sustainability of biofuels. However, the research reiterates what other, more independent researchers have found before.
Ethanol Raises Net Carbon Emissions
For example, in 2014, the Environmental Working Group (EWG) released a report titled “Ethanol’s Broken Promise,”3 which reached similar conclusions as DeCicco’s study. It too concluded that corn ethanol is worse for the environment than gasoline.
One of the primary reasons why growing corn for ethanol has a net-positive carbon impact is because farmers are plowing up native grasslands to make more room for corn. The failure to take this change in land use into account is how proponents of biofuels have been able to perpetuate the myth that it’s carbon neutral.
According to EWG, more than 8 million acres of grassland and wetlands were converted to corn between 2008 and 2011 alone, and every time an acre of grassland is plowed, 60 tons of carbon dioxide are released into the environment.4
So, while the ethanol fuel program was designed to reduce carbon emissions, the loss of grasslands does just the opposite. Estimates showing corn ethanol’s positive influence on the environment have also failed to consider the water needed to grow the corn.
“Ignoring water constraints underestimates emissions from land-use change by 28%,” EWG reported.5 According to agricultural economists at Purdue University, when corn plants’ water needs are considered, corn ethanol is worse for the environment than gasoline.6
The EWG also cited data debunking the false claim that ethanol has no impact on the price of corn and other agricultural commodities. According to scientists with the National Academies, the radical change in the proportion of corn used for ethanol resulted in the price of corn rising by 20% and 40% between 2007 and 2009 alone. This is partly why anti-hunger organizations have been so against corn-based ethanol.
The Many Downsides of Biofuels
A five-year study7,8 published in Proceedings of the National Academy of Science (PNAS) in February 2022 also came down hard on…
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