N2O emissions from the global agricultural nitrogen cycle – current state and future scenarios Potsdam Institute for Climate Impact Research (PIK), P.O. Box 60 12 03, 14412 Potsdam, Germany
31 Oct 2012
Received: 06 February 2012 – Published in Biogeosciences Discuss.: 13 March 2012 Abstract. Reactive nitrogen (Nr) is not only an important nutrient for plant growth,
thereby safeguarding human alimentation, but it also heavily disturbs natural
systems. To mitigate air, land, aquatic, and atmospheric pollution caused by
the excessive availability of Nr, it is crucial to understand the long-term
development of the global agricultural Nr cycle.
Revised: 19 September 2012 – Accepted: 20 September 2012 – Published: 31 October 2012
For our analysis, we combine a material flow model with a
land-use optimization model. In a first step we estimate the state of the Nr
cycle in 1995. In a second step we create four scenarios for the 21st century
in line with the SRES storylines.
Our results indicate that in 1995 only half of the Nr applied to croplands
was incorporated into plant biomass. Moreover, less than 10 per cent of
all Nr in cropland plant biomass and grazed pasture was consumed by humans. In our
scenarios a strong surge of the Nr cycle occurs in the first half of the
21st century, even in the environmentally oriented scenarios. Nitrous oxide
(N2O) emissions rise from 3 Tg N2O-N in 1995 to 7–9 in 2045 and 5–12 Tg
in 2095. Reinforced Nr pollution mitigation efforts are therefore required.
Citation: Bodirsky, B. L., Popp, A., Weindl, I., Dietrich, J. P., Rolinski, S., Scheiffele, L., Schmitz, C., and Lotze-Campen, H.: N2O emissions from the global agricultural nitrogen cycle – current state and future scenarios, Biogeosciences, 9, 4169-4197, doi:10.5194/bg-9-4169-2012, 2012.