Regional variability in peatland burning at mid-to high-latitudes during the Holocene

Date

2023

Authors

Sim, Thomas G.
Swindles, Graeme T.
Morris, Paul J.
Baird, Andy J.
Gallego-Sala, Angela V.
Wang, Yuwan
Blaauw, Maarten
Camill, Philip
Garneau, Michelle
Hardiman, Mark

Journal Title

Journal ISSN

Volume Title

Publisher

Quaternary Science Reviews

Abstract

Northern peatlands store globally-important amounts of carbon in the form of partly decomposed plant detritus. Drying associated with climate and land-use change may lead to increased fire frequency and severity in peatlands and the rapid loss of carbon to the atmosphere. However, our understanding of the patterns and drivers of peatland burning on an appropriate decadal to millennial timescale relies heavily on individual site-based reconstructions. For the first time, we synthesise peatland macrocharcoal records from across North America, Europe, and Patagonia to reveal regional variation in peatland burning during the Holocene. We used an existing database of proximal sedimentary charcoal to represent regional burning trends in the wider landscape for each region. Long-term trends in peatland burning appear to be largely climate driven, with human activities likely having an increasing influence in the late Holocene. Warmer conditions during the Holocene Thermal Maximum (∼9–6 cal. ka BP) were associated with greater peatland burning in North America's Atlantic coast, southern Scandinavia and the Baltics, and Patagonia. Since the Little Ice Age, peatland burning has declined across North America and in some areas of Europe. This decline is mirrored by a decrease in wider landscape burning in some, but not all sub-regions, linked to fire-suppression policies, and landscape fragmentation caused by agricultural expansion. Peatlands demonstrate lower susceptibility to burning than the wider landscape in several instances, probably because of autogenic processes that maintain high levels of near-surface wetness even during drought. Nonetheless, widespread drying and degradation of peatlands, particularly in Europe, has likely increased their vulnerability to burning in recent centuries. Consequently, peatland restoration efforts are important to mitigate the risk of peatland fire under a changing climate. Finally, we make recommendations for future research to improve our understanding of the controls on peatland fires.

Description

Records from the Global Charcoal Database supplemented this work and therefore we would like to thank the contributors and managers of this open-source resource. We also thank Annica Greisman, Jennifer Shiller, Fredrik Olsson and Simon van Bellen for contributing charcoal data to our analyses.

Keywords

Fire, Charcoal, Palaeofire, Palaeoenvironments, Data analysis, North America, Europe, Patagonia, Carbon balance, Drought

Citation

Sim, T. G., Swindles, G. T., Morris, P. J., Baird, A. J., Gallego-Sala, A. V., Wang, Y., … Zhang, H. (2023). Regional variability in peatland burning at mid-to highlatitudes during the Holocene. Quaternary Science Reviews, 305, 108020. https://doi.org/10.1016/j.quascirev.2023.108020.