Holocene changes in biomass burning in the boreal Northern Hemisphere, reconstructed from anhydrosugar fluxes in an Arctic sediment profile

Afeng Chen; Lianjiao Yang; Liguang Sun; Yuesong Gao; Zhouqing Xie

doi:10.1016/j.scitotenv.2023.161460

Holocene changes in biomass burning in the boreal Northern Hemisphere, reconstructed from anhydrosugar fluxes in an Arctic sediment profile

Sci Total Environ. 2023 Apr 1:867:161460. doi: 10.1016/j.scitotenv.2023.161460. Epub 2023 Jan 7.

Authors

Afeng Chen¹, Lianjiao Yang¹, Liguang Sun¹, Yuesong Gao², Zhouqing Xie³

Affiliations

¹ Institute of Polar Environment & Anhui Key Laboratory of Polar Environment and Global Change, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China.
² Institute of Polar Environment & Anhui Key Laboratory of Polar Environment and Global Change, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China. Electronic address: yuesgao@ustc.edu.cn.
³ Institute of Polar Environment & Anhui Key Laboratory of Polar Environment and Global Change, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China. Electronic address: zqxie@ustc.edu.cn.

PMID: 36626988
DOI: 10.1016/j.scitotenv.2023.161460

Abstract

The rapid warming of Arctic is causing increased fire activities in the boreal Northern Hemisphere (NH), leading to unprecedent changes in the global carbon cycling, human health and ecosystems. Understanding the interaction between fire and climate in this far north region is crucial for predicting future changes of wildfires. However, fire records over geological time scales are still scarce in the high latitudes of NH to provide comprehensive pictures of the fire history in this region. Here, we used the flux of levoglucosan (Lev) and its isomers in a sediment profile YN from Svalbard, high Arctic, as proxies for the changes in biomass burning from ∼9-2 kyr BP (thousand years before present). Backward trajectories and comparison with charcoal syntheses from various regions confirmed that the Lev transport to the profile site is sourced from the fire activities in the boreal NH, especially in northern Europe and northern Siberia. The Lev flux exhibited a slight overall decreasing trend at ∼3 %/kyr (p = 0.09) over the study period, as well as centennial maxima at ∼9, 8-7, 6, 5, and 4-3 kyr BP (p = 0.06). On sub-orbital scales, the long-term decrease in fire activities corresponded to trends of summer temperature in the extratropics of the NH (p = 0.01, r = 0.42), reflecting their regulation of fuel availability and flammability. On centennial to sub-millennial time scales, high levels of biomass burning were associated with periods of increased North Atlantic ice-rafted debris (p = 0.02, r = 0.38), which were indicative of cold and dry conditions over most of the source regions, reflecting the impacts of dryness on fuel flammability. The results suggested that enhanced Arctic amplification on centennial time scales may reduce biomass burning in most of the boreal NH, although fires in some mid-latitude regions may be facilitated.

Keywords: Anhydrosugar; Arctic; Climate change; Fire history; Holocene; Levoglucosan; Northern Hemisphere; Ny-Ålesund.