Abstract
Abstract. Biomass burning influences global atmospheric chemistry by releasing greenhouse gases and climate-forcing aerosols. There is controversy about the magnitude and timing of Holocene changes in biomass burning emissions from millennial to centennial timescales and, in particular, about the possible impact of ancient civilizations. Here we present a 5 kyr record of fire activity proxies levoglucosan, black carbon, and ammonium measured in the RECAP (Renland ice cap) ice core, drilled in coastal eastern Greenland, and therefore affected by processes occurring in the high North Atlantic region. Levoglucosan and ammonium fluxes are high from 5 to 4.5 kyr BP (thousand years before 2000 CE) followed by an abrupt decline, possibly due to monotonic decline in Northern Hemisphere summer insolation. Levoglucosan and black carbon show an abrupt decline at 1.1 kyr BP, suggesting a decline in the wildfire regime in Iceland due to the extensive land clearing caused by Viking colonizers. All fire proxies reach a minimum during the second half of the last century, after which levoglucosan and ammonium fluxes increase again, in particular over the last 200 years. We find that the fire regime reconstructed from RECAP fluxes seems mainly related to climatic changes; however over the last millennium human activities might have influenced wildfire frequency/occurrence substantially.
Highlights
Extensive wildfires, at high latitudes, have recently generated worldwide attention and raised concerns about the impacts of humans and climate change on fire regimes
The RECAP levoglucosan flux is significantly correlated with reconstructed Northern Hemisphere temperature (r = 0.46, p < 0.001) as well as with RECAP δ18O (r = 0.33, p < 0.01); the RECAP black carbon (BC) flux is significantly correlated with NH temperature (r = 0.32, p < 0.001) and with RECAP δ18O (r = 0.29, p < 0.01)
From back-trajectory analysis and the comparison with regional fire reconstructions based on charcoal records, we find that the most likely source area of impurities arriving at Renland is the high North Atlantic region and comprehends the Greenland Ice Sheet, the coasts of Greenland, and Iceland
Summary
At high latitudes, have recently generated worldwide attention and raised concerns about the impacts of humans and climate change on fire regimes. During summer 2020 wildfires over the Arctic Circle emitted 35 % more CO2 than the previous year, with a significant contributor being peatland fires (Witze, 2020). Little is known about the patterns and driving forces of fire activity in the past. Quantitative observations of wildfires are severely limited both in time and space, and coverage in global datasets based on satellite observations began in 1974 (Chuvieco et al, 2019). Fire is influenced by human activities, vegetation, and climate, and it is a key Earth system process (Bowman et al, 2009; Keywood et al, 2013). As a major component of the carbon cycle, fire interacts with the climate system by re-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
