Thursday, February 24, 2022

This essay was authored by Professor Silvia Secchi

Is ethanol really green? No, and I told you so.

Portrait of Silvia Secchi

Those who listen to the We All Want Clean Water podcast have heard me say three times that ethanol is not “green”, excepting of course cream de mint and Old Style at a Wrigleyville tavern on March 17. So I beg your forgiveness for being so repetitive, but it is really important for the public to understand, which is why Dr. Jones has graciously agreed to give me some space to talk about it here.

Why is the issue coming up again now? First, the Renewable Fuel Standard, which mandates the amount of corn ethanol to be blended with gasoline, and therefore heavily influences the corn market, requires the Environmental Protection Agency to decide this year what the mandate level is going to be going forward, and the mandate has minimum requirements on the reductions in greenhouse gas (GHG) emissions from ethanol. For context, we use over half of Iowa’s corn crop for ethanol (almost 40% nationally) so this is a big deal. Secondly, California’s Low Carbon Fuel Standard gives preferential treatment to fuels with lower GHG emissions, and Iowa’s ethanolians are quite keen to get a bigger slice of this California green pie (one really has to wonder why they aren’t clamoring with the same enthusiasm to meet the demands of California’s meat consumers). Third, the next farm bill is coming up and with all the focus on carbon payments and agriculture’s role in fighting climate change (for a modest subsidy, of course), it would not look good to expose ethanol as causing climate change instead of reducing it. It might make some people wonder why we keep subsidizing its main input, King Corn. So, whether you are a climate denier or not, it pays to produce a “green” fuel, at least until recently.

It so happens that last week a stellar group of researchers from several land grant institutions published a paper in the prestigious journal Proceedings of the National Academies of Science (PNAS) which showed that ethanol causes more GHG emissions than gasoline, and it also has a bunch of other bad effects because of its impact on American land use. As an aside, many of you know I have this nasty habit of criticizing land grant research, though of course I have produced some myself. This one made me eat my hat and I’d be happy to do so on a daily basis if the land grant universities regularly did such good work on agricultural issues. Bring it. 


Now, I was fine with the hat indigestion since the paper proved that, well over a decade ago, I was correct in pointing out that the environmental effects of ethanol would be terrible for Iowa, the Midwest and beyond. Let me tell you, nothing makes a professor happier than to be proven right, even when the journal publishing those results now rejected one of my papers then. We predicted that the ethanol mandate would have negative consequences on water quality and other environmental indicators such as soil carbon. These effects occur via two channels. First, farmers plant more corn after corn, instead of the usual corn-soybeans rotations, and may also increase the rates of fertilizer applications to increase yield or reduce the risk of yield loss. This is what we call intensification. Second, we anticipated that we would see land use change from conservation set asides such as the Conservation Reserve Program and from pastures and grasslands into cropland. The increases in land rental rates would make conservation more expensive and grazing less attractive. This is what we call extensification. Our focus was predicting changes that had not yet happened and on water quality, the PNAS study looks at whether the changes we predicted actually happened at the national scale and comprehensively considers both water and GHG emissions. Lo and behold, they find that the water got worse and that more land went into annual crop production and corn specifically so higher ethanol production actually caused more carbon to be released in the atmosphere than if we had used gasoline. The study is remarkable because it shows that these effects in the US alone are enough to make ethanol a loss not just for the taxpayers who have been subsidizing it directly or indirectly for decades, but also for the climate.

The effects in other parts of the world are likely to have been much more devastating. For example, people in Southeast Asia have cut down peatland rain forests to plant oil palms to produce biodiesel. Since those forests store a lot of carbon, and the first thing that needs to be done before planting the palms is to burn the peat, the “forgotten fossil fuel”, a 2008 Science paper estimated that it would take over 400 years for the carbon released in the atmosphere from the change in land use to be paid back by the reductions in emissions from the biodiesel from the oil palms. Similarly, if we grow more corn for ethanol in the US, and less soybeans, then Brazil will grow more soybeans. Brazil may use land that was used as pasture for the soybeans and cut down Amazonian rain forest for grazing. Since the Amazon is a very good carbon sink, this causes more net GHG emissions from corn ethanol compared with gasoline. The problems are  that 1) it is not easy to determine how much of the price change (and associated land use change) is coming from ethanol and how much is coming from say China’s increased demand for pork, and 2) the data on land use change can have errors. The industry has been using this uncertainty for years to argue that there was not enough evidence on the ground, and was funding its own studies which – predictably – prove the opposite. Another aside – I wish all the ethanol shills from the land grants would disclose if they have received industry funding when they speak about it. Some work on global impacts - based by necessity on coarse data – found that global GHG emissions were lower but the PNAS study has much more granular data, and includes effects on water quality.  

We always knew fuel ethanol was a pyrrhic choice, at least for the public, one that gave us more degraded water for an at-best modest climate benefit. However, if you’re one of the lucky few to own some Iowa farmland, the benefit has been sensational, as land prices have increased in lockstep with RFS-mandated ethanol production levels. The ethanolians have never been visionaries, but they are at least smart enough to see that the PNAS paper could turn the tide; they’ve predictably circled their wagons and are so furiously spreading their BS on the frozen Iowa landscape that there’s hardly room for Iowa’s hog manure.

The national security crutch argument for ethanol has been kicked away by fracking, and now the dirtier water-for-cleaner air argument has been drowned in the PNAS bathtub. Couple this with the fact that cellulosic ethanol is now passed out and still five years away after fifty years, corn ethanol has conclusively been proven to be a lose-lose-lose proposition. There’s no reason to build pipelines for an already shattered pipe dream.