Table 1.
Net changes due to the RFS
| Land use | GHG emissions | Environmental indicators | |||||||
| Corn area (Mha y−1) | Cropland area (Mha) | Nitrous oxide (TgCO2e y−1) | Ecosystem carbon (TgCO2e) | N applied (Gg-N y−1) | P applied (Gg-P y−1) | Nitrate leaching (Gg-N y−1) | P runoff (Mg-P y−1) | Soil erosion (Gg y−1) | |
| Crop rotation Δ | 2.8 | — | 2.8 | — | 480.0 | 21.3 | 87.1 | 203.2 | 222.9 |
| 95% CI lower limit | 2.4 | — | 2.3 | — | 377.3 | 1.2 | 56.9 | −27.7 | 11.6 |
| 95% CI upper limit | 3.1 | — | 3.2 | — | 577.0 | 41.2 | 117.7 | 449.3 | 423.6 |
| Cropland extent Δ | — | 2.1 | 1.3 | 397.7 | 237.3 | 48.2 | 47.9 | 439.0 | 633.9 |
| 95% CI lower limit | — | 1.8 | 1.0 | 313.3 | 190.5 | 38.4 | 33.5 | 273.6 | 485.9 |
| 95% CI upper limit | — | 2.5 | 1.5 | 481.7 | 281.8 | 57.7 | 62.1 | 592.6 | 780.6 |
| Combined total Δ | 2.8 | 2.1 | 4.1 | 397.7 | 717.2 | 69.5 | 135.0 | 642.2 | 856.7 |
| 95% CI lower limit | 2.4 | 1.8 | 3.5 | 313.3 | 626.7 | 58.9 | 111.6 | 476.9 | 697.6 |
| 95% CI upper limit | 3.1 | 2.5 | 4.5 | 481.7 | 806.5 | 79.5 | 157.8 | 798.0 | 1,011.4 |
| BAU baseline | 31.7 | 88.4 | 48.6 | — | 9,545.5 | 1,986.4 | 2,535.5 | 19,939.3 | 18,038.7 |
| %Δ from BAU | 8.7% | 2.4% | 8.3% | — | 7.5% | 3.5% | 5.3% | 3.2% | 4.7% |
| %Δ per BGY | 1.6% | 0.4% | 1.5% | — | 1.4% | 0.6% | 1.0% | 0.6% | 0.9% |
%Δ from BAU = percent change from BAU; i.e., the incremental effect of the 2007 expansion of the RFS; %Δ per BGY = percent change per BGY increase in ethanol demand.