N2O changes from the Last Glacial Maximum to the preindustrial – Part 2: terrestrial N2O emissions and carbon–nitrogen cycle interactions ...

• Main Authors: Joos, Fortunat, Spahni, Renato, Stocker, Benjamin, Lienert, Sebastian, Müller, Jurek, Fischer, Hubertus, Schmitt, Jochen, Prentice, I. Colin, Otto-Bliesner, Bette, Liu, Zhengyu
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2020
• Subjects: ice core
• Online Access: https://dx.doi.org/10.3929/ethz-b-000429152; http://hdl.handle.net/20.500.11850/429152

Carbon–nitrogen (C–N) interactions regulate N availability for plant growth and for emissions of nitrous oxide (N2O) and the uptake of carbon dioxide. Future projections of these terrestrial greenhouse gas fluxes are strikingly divergent, leading to major uncertainties in projected global warming. Here we analyse the large increase in terrestrial N2O emissions over the past 21 000 years as reconstructed from ice-core isotopic data and presented in part 1 of this study. Remarkably, the increase occurred in two steps, each realized over decades and within a maximum of 2 centuries, at the onsets of the major deglacial Northern Hemisphere warming events. The data suggest a highly dynamic and responsive global N cycle. The increase may be explained by an increase in the flux of reactive N entering and leaving ecosystems or by an increase in N2O yield per unit N converted. We applied the LPX-Bern dynamic global vegetation model in deglacial simulations forced with Earth system model climate data to investigate N2O ... : Biogeosciences, 17 (13) ...