Fig. 2.
GHG emissions associated with the N fertilizer chain in China. Emission amounts for 1980–2010 were calculated using emission factors (Fig. 1) derived from a 2005 survey and annual N production and consumption records. Emission estimates for 2020 and 2030 consider four scenarios: scenario 1, business-as-usual; scenario 2, improved manufacturing technologies; scenario 3, improved manufacturing technologies plus controlled N use; and scenario 4, improved manufacturing technologies with reduced N use on croplands.