Modelling terrestrial nitrous oxide emissions and implications for climate feedback
Article first published online: 24 AUG 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 196, Issue 2, pages 472–488, October 2012
How to Cite
New Phytologist (2012)196: 472–488
- Issue published online: 17 SEP 2012
- Article first published online: 24 AUG 2012
- Manuscript Accepted: 8 JUL 2012
- Manuscript Received: 18 MAY 2012
- National Natural Science Foundation of China. Grant Numbers: 40975096, 40871032, 41175128
- climate feedback;
- CO 2 ;
- dynamic global vegetation model;
- greenhouse gas;
- nitrogen cycle;
- nitrous oxide (N2O)
- Ecosystem nitrous oxide (N2O) emissions respond to changes in climate and CO2 concentration as well as anthropogenic nitrogen (N) enhancements. Here, we aimed to quantify the responses of natural ecosystem N2O emissions to multiple environmental drivers using a process-based global vegetation model (DyN-LPJ).
- We checked that modelled annual N2O emissions from nonagricultural ecosystems could reproduce field measurements worldwide, and experimentally observed responses to step changes in environmental factors. We then simulated global N2O emissions throughout the 20th century and analysed the effects of environmental changes.
- The model reproduced well the global pattern of N2O emissions and the observed responses of N cycle components to changes in environmental factors. Simulated 20th century global decadal-average soil emissions were c. 8.2–9.5 Tg N yr−1 (or 8.3–10.3 Tg N yr−1 with N deposition). Warming and N deposition contributed 0.85 ± 0.41 and 0.80 ± 0.14 Tg N yr−1, respectively, to an overall upward trend. Rising CO2 also contributed, in part, through a positive interaction with warming.
- The modelled temperature dependence of N2O emission (c. 1 Tg N yr−1 K−1) implies a positive climate feedback which, over the lifetime of N2O (114 yr), could become as important as the climate–carbon cycle feedback caused by soil CO2 release.