Millennial changes in North American wildfire and soil activity over the last glacial cycle

Fischer, Hubertus; Schupbach, Simon; Gfeller, Gideon; Bigler, Matthias; Rothlisberger, Regine; Erhardt, Tobias; Stocker, Thomas F; Mulvaney, Robert ORCID: https://orcid.org/0000-0002-5372-8148; Wolff, Eric W. 2015 Millennial changes in North American wildfire and soil activity over the last glacial cycle. Nature Geosciences, 8 (9). 723-727. https://doi.org/10.1038/ngeo2495

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Abstract/Summary

Climate changes in the North Atlantic region during the last glacial cycle were dominated by the slow waxing and waning of the North American ice sheet as well as by intermittent, millennial-scale Dansgaard–Oeschger climate oscillations. However, prior to the last deglaciation, the responses of North American vegetation and biomass burning to these climate variations are uncertain. Ammonium in Greenland ice cores, a product from North American soil emissions and biomass burning events, can help to fill this gap. Here we use continuous, high-resolution measurements of ammonium concentrations between 110,000 to 10,000 years ago from the Greenland NGRIP and GRIP ice cores to reconstruct North American wildfire activity and soil ammonium emissions. We find that on orbital timescales soil emissions increased under warmer climate conditions when vegetation expanded northwards into previously ice-covered areas. For millennial-scale interstadial warm periods during Marine Isotope Stage 3, the fire recurrence rate increased in parallel to the rapid warmings, whereas soil emissions rose more slowly, reflecting slow ice shrinkage and delayed ecosystem changes. We conclude that sudden warming events had little impact on soil ammonium emissions and ammonium transport to Greenland, but did result in a substantial increase in the frequency of North American wildfires.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1038/ngeo2495
Programmes:	BAS Programmes > BAS Programmes 2015 > Ice Dynamics and Palaeoclimate
ISSN:	17520894
Additional Keywords:	climate change
Date made live:	21 Sep 2015 08:22 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/511166

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1038/ngeo2495

Programmes:

BAS Programmes > BAS Programmes 2015 > Ice Dynamics and Palaeoclimate

ISSN:

17520894

Additional Keywords:

climate change

Date made live:

21 Sep 2015 08:22 +0 (UTC)