Isotopic constraints on marine and terrestrial N2O emissions during the last deglaciation

Schilt, Adrian; Brook, Edward J.; Bauska, Thomas K.; Baggenstos, Daniel; Fischer, Hubertus; Joos, Fortunat; Petrenko, Vasilii V.; Schaefer, Hinrich; Schmitt, Jochen; Severinghaus, Jeffrey P.; Spahni, Renato; Stocker, Thomas F. (2014). Isotopic constraints on marine and terrestrial N2O emissions during the last deglaciation. Nature, 516(7530), pp. 234-237. Macmillan Journals Ltd. 10.1038/nature13971

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Nitrous oxide (N2O) is an important greenhouse gas and ozone-depleting substance that has anthropogenic as well as natural marine and terrestrial sources. The tropospheric N2O concentrations have varied substantially in the past in concert with changing climate on glacial–interglacial and millennial timescales. It is not well understood, however, how N2O emissions from marine and terrestrial sources change in response to varying environmental conditions. The distinct isotopic compositions of marine and terrestrial N2O sources can help disentangle the relative changes in marine and terrestrial N2O emissions during past climate variations. Here we present N2O concentration and isotopic data for the last deglaciation, from 16,000 to 10,000 years before present, retrieved from air bubbles trapped in polar ice at Taylor Glacier, Antarctica. With the help of our data and a box model of the N2O cycle, we find a 30 per cent increase in total N2O emissions from the late glacial to the interglacial, with terrestrial and marine emissions contributing equally to the overall increase and generally evolving in parallel over the last deglaciation, even though there is no a priori connection between the drivers of the two sources. However, we find that terrestrial emissions dominated on centennial timescales, consistent with a state-of-the-art dynamic global vegetation and land surface process model that suggests that during the last deglaciation emission changes were strongly influenced by temperature and precipitation patterns over land surfaces. The results improve our understanding of the drivers of natural N2O emissions and are consistent with the idea that natural N2O emissions will probably increase in response to anthropogenic warming.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Physics Institute > Climate and Environmental Physics
08 Faculty of Science > Physics Institute

UniBE Contributor:

Schilt, Adrian; Fischer, Hubertus; Joos, Fortunat; Schmitt, Jochen; Spahni, Renato and Stocker, Thomas

Subjects:

500 Science > 530 Physics
500 Science > 550 Earth sciences & geology

ISSN:

0028-0836

Publisher:

Macmillan Journals Ltd.

Language:

English

Submitter:

Doris Rätz

Date Deposited:

09 Jan 2015 08:41

Last Modified:

10 Sep 2015 10:24

Publisher DOI:

10.1038/nature13971

BORIS DOI:

10.7892/boris.61467

URI:

https://boris.unibe.ch/id/eprint/61467

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