A new study shows that corn-based ethanol may be worse for the climate than gasoline

Ethanol, made from corn grown on millions of acres of U.S. farmland, has become the nation’s main renewable fuel, touted as a low-carbon alternative to traditional gasoline and a key component of the country’s efforts to reduce greenhouse gas emissions.

But new studypublished this week, finds that corn-based ethanol can be worse for the climate than fossil-based gasoline, and has other environmental downsides.

“We thought and hoped it would be a climate solution and reduce and replace our dependence on gasoline,” said Tyler Lark, a researcher at the Nelson Institute for Environmental Research at the University of Wisconsin, Madison, and lead author of the study. “It turns out it’s no better for the climate than gasoline, which it seeks to replace, and faces a variety of other impacts.”

A study published in the Proceedings of the National Academy of Sciences examines specifically the impact of the Renewable Fuel Standard (RFS), which was first adopted by Congress in 2005 and updated in 2007 (RFS2). The standard requires blenders to add billions of gallons of renewable fuel annually to the country’s transportation fuel supplies, creating the world’s largest biofuel program.

At the time, lawmakers and supporters hailed the standard as a great victory for the climate and part of a concerted effort to reduce dependence on foreign oil.

But 15 years after that, his promises have not yet been fulfilled, critics say, and a growing body of research shows that corn ethanol not reduced demand for fossil fuels, as expected, but instead forced to convert meadows and forests into agricultural land, both domestically and internationally, emitting carbon in the process.

In a new study, Lark and colleagues found that after the RFS went into effect, farmers increased corn production by nearly 7 million hectares each year, causing land conversion to sowing, “so the carbon intensity of corn ethanol produced under the RFS, is no less than gasoline and probably at least 24% higher. ” Policies, the study said, have also led to increased fertilizer use, water pollution and habitat loss.

У preliminary studysince 2019, Lark and his colleagues have found that expanding arable land in the United States, mainly for corn and soybeans, has led to increased greenhouse gas emissions, but has not linked this expansion to RFS.

After the current standard came into force in 2007, the Environmental Protection Agency, which is responsible for implementing the program, determined that corn ethanol meets the requirement that any renewable fuel under the program must demonstrate a 20 percent reduction in greenhouse gas emissions. gases compared to gasoline.

But the following year, researchers published the study in a journal Science predicting that corn ethanol will double greenhouse gas emissions in 30 years because demand for corn will push farmers to plow more carbon-rich forests and meadows. This is a study provoked a long debate about the benefits of carbon ethanol.

In subsequent years, the U.S. Department of Agriculture and researchers from well-known agricultural universities conducted research showing that corn-based ethanol reduced greenhouse gas emissions by 40-45 percent.

In response to a new document from the Renewable Fuel Association (RFA) pointed to these studies and said: “The claims in this report simply do not correspond to reality and facts on the ground, and the newspaper is more like a fiction novel than real academic literature.”

Tim Poshukinger, a researcher at Princeton University, author Science A 2008 study that predicts doubling greenhouse gas emissions in 30 years says a study the RFA uses to support the climatic benefits of ethanol does not properly address land use change, or it underestimates carbon emissions from the conversion of forests and meadows into respect.

“Their numbers are invented from solid fabric,” Searchhucker said.

The RFA notes that cornfields have not expanded since the standard was introduced, but the study’s authors say they have instead proven “against the fact.”

“What matters is what would have been without RFS, without this ethanol boom,” Lark said. “Without this policy, there would have been a significant reduction in corn.”

The goal of RFS and RFS2 was to make other types of renewable fuels, especially cellulosic ethanol from plant and wood fibers, increasingly becoming part of the fuel mix. But this has not yet happened. Instead, the basis of the program was corn.

The Biden administration is going to review the “Renewable Volume Commitment” – the percentage of renewable fuel required by the fuel mixture under the law – in the coming months. The Senate Committee on the Environment and Public Works is scheduled hold a hearing on Wednesday RFU.

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Aaron Smith, a co-author of the study and professor of agricultural economics at the University of California at Davis, said they decided to analyze the impact of RFS now, in part because of upcoming reviews and possible changes to the program.

“The law says we need to look at the impact of RFS on the environment,” Smith said. “And what struck us was the impact of carbon.”

John Reilly, honored co-director of the Massachusetts Institute of Technology’s Joint Program on Global Change Science and Policy and a longtime researcher with the Department of Agriculture, called the study “impressive work” that is likely to spark further debate between environmental groups and the biofuels industry. .

“The real supposed advantage of RFS2 was to stimulate the production of second-generation biofuels from cellulosic material, which should have been much more environmentally friendly,” said Reilly. “In this regard, the regulations are an impressive failure. If further research confirms the results of this study on corn ethanol, then RFS2 will suffer an impressive failure on two fronts ”. A new study shows that corn-based ethanol may be worse for the climate than gasoline

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