This month, the Environmental Protection Agency once again proposed an uptick in the billions of gallons of biofuels—mostly corn ethanol and biodiesel—that Americans must put in their autos and other vehicles as we hit the travelling season of summer.
It was another triumph of politics over real environmental concern.
The new total of mandated biofuels under the latest revision of the Renewable Fuel Standard, or RFS, is nearly 700 million gallons more than last year. That is not as much as Congress called for, but still based on a badly flawed assumption: that biofuels produce lower emissions of CO2 and other greenhouse gases than petroleum-based fuels.
By now, EPA should know better, given the clear-cut evidence of how that assumption is wrong.
As with many scientific questions, the correct answer is, "it depends." The right answer comes from careful accounting that tracks both the flow of CO2 from the atmosphere down to the cropland that grows corn and soybeans and the flow of CO2 back up into the air from tailpipe emissions when biofuels are burned.
Once the books are properly audited, it turns out that the RFS puts more carbon into the air than gets removed by the crops used to make the renewable fuels that the policy requires.
Yet EPA still claims that the RFS is helping to reduce CO2 emissions.
This non-sense can be traced to another instance of Congressional overreach. When Congress expanded the biofuel mandate in 2007, lawmakers told EPA to use a conveniently rigged form of accounting when assessing the impact of the RFS.
Known as lifecycle assessment (LCA), this approach to keeping the books on carbon is complicated but only semi-scientific. Its results depend as much on the assumptions baked into LCA computer models as they do on real-world data.
The method is rigged in favor of biofuels because it assumes that they are automatically carbon neutral—that the amount of CO2 released when they are burned is the same as the total removed from the atmosphere when corn, soybeans or other energy crops are grown in the first place.
This dubious approach to carbon accounting was underwritten, and is still heavily promoted, by the federal Department of Energy. It was also embraced by green groups that teamed up with the biofuels industry to lobby for a greatly expanded biofuel mandate.
Unfortunately, they didn't pay attention to the principles given by the International Standards Organization (ISO) for use of their method. Those guidelines state that "there is no scientific basis for reducing LCA results to a single overall score or number, since weighting requires value choices."
Yet that's exactly what the law requires EPA to do. With the RFS, Congress created a regulation that enables politically convenient "value choices" when weighing the factors that shape how carbon footprint calculations come out.
Those who oppose the fuels are neither climate deniers nor tools of the oil and gas industry. More careful carbon accounting now seems accepted elsewhere in the Obama Administration, which did not claim emission savings from biofuels in its most recent list of carbon-cutting measures presented to the United Nations Framework Convention on Climate Change.
Science can tell us when biofuel production might be plausibly helpful for protecting the climate. That can only occur if growing a biofuel's feedstock greatly speeds up how quickly CO2 is removed from the air on a net basis.
But this beneficial balance doesn't happen for the corn ethanol and the soybean biodiesel that the RFS forces through America's fuel pumps in greater volumes each year.
So here we are, eleven years and counting since Congress decided to mandate renewable fuel—and the math is still bad.
With its latest RFS proposal, the agency saddled with carrying out this act of central planning is trying to chart a course between the fantasies of biofuel advocates and the realities of the marketplace. But any such course is still an ecological calamity that worsens CO2 emissions.
To deal with this distorted situation, Congress should repeal the RFS or at least scale it way back.
And it should eliminate the lifecycle requirements that foster bad bookkeeping and misleading claims about biofuel's environmental benefits
Environmental policies can be contentious at the best of times. We don’t need bad math to make the situation worse when we are struggling to make it better.
John M. DeCicco is a research professor at the University of Michigan Energy Institute, where his work addresses the environmental implications of energy use.