How Does Ethanol Contribute to Global Warming?

How Does Ethanol Contribute to Global Warming?

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How does ethanol contribute to global warming?

DOE Sources of CO2The yellow dots on this map are ethanol plants. They are sources of CO2 emissions, a major  greenhouse gas contributing to global warming.

Corn ethanol contributes to global warming through several pathways:

Fossil fuel use

Ethanol requires fossil fuel at nearly every aspect of its production. Growing the corn involves fossil-fueled and greenhouse gas-emitting tractors, crop sprayers, and harvesting combines.

Industrially grown corn also requires high inputs of fossil-fuel based fertilizers. Fossil fuels are further required to truck the corn material to processing plants.

In ethanol production, fossil fuels are needed to grind, heat and cool the corn to make it ferment. Lastly, because ethanol cannot be transported in current fuel pipelines, ethanol has to be trucked everywhere.


When ethanol is burned in cars, acetaldehyde, nitrous oxide, methane and formadelyhde are released.  Some of these chemicals are released at levels higher than conventional gasoline.

Land use change

As more land is required for meeting ethanol and biofuel demands set by the U.S. and Europe, forests, rainforests and grasslands are torn up. These ecosystems hold carbon within their plant life, and when they are cut down, the carbon is released into the atmosphere. In fact, a study by Princeton University and the Nature Conservancy found that land use change from biofuel production will actually make carbon emissions worse for the next hundred years.