Diesel burned to plant and harvest and transport the corn.
Coal burned to make electricity for converting corn to ethanol.
Ethanol, with current year carbon from atmospere, burned as fuel returns carbon to atmosphere. (Beer drinker drinks all the beer at the end of the year)
I see an increase in carbon released.
--I see an increase in carbon released.--
But the NET released (burned less recycled) is less.
Say now we are releasing X units. With biofuels we will be releaseing Y units where Y is greater than X. But we will be capturing Z units.
The net will be Y - Z which will be less than Z.