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Biomass burning plays an important role in climate-forcing and atmospheric chemistry. The drivers of fire activity over the past two centuries, however, are hotly debated and fueled by poor constraints on the magnitude and trends of preindustrial fire regimes. As a powerful tracer of biomass burning, reconstructions of paleoatmospheric carbon monoxide (CO) can provide valuable information on the evolution of fire activity across the preindustrial to industrial transition. Here too, however, significant disagreements between existing CO records currently allow for opposing fire histories. In this study, we reconstruct a continuous record of Antarctic ice core CO between 1821 and 1995 CE to overlap with direct atmospheric observations. Our record indicates that the Southern Hemisphere CO burden ([CO]) increased by 50% from a preindustrial mixing ratio of ca. 35 ppb to ca. 53 ppb by 1995 CE with more variability than allowed for by state-of-the-art chemistry-climate models, suggesting that historic CO dynamics have been not fully accounted for. Using a 6-troposphere box model, a 40 to 50% decrease in Southern Hemisphere biomass-burning emissions, coincident with unprecedented rates of early 20th century anthropogenic land-use change, is identified as a strong candidate for this mismatch.
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Chemical, elemental, and isotopic measurements of the archived HT95 (Hans Tausen 1995) ice core from northern Greenland spanning the past ~5600 years
The specific goal of this project was to develop a more complete and quantitative understanding of natural and anthropogenic drivers of biomass burning over the Common Era. To do so, new high-resolution measurements of a broad range of chemical, elemental, and isotopic species were analyzed on the archived HT95 core using the continuous flow analysis system at the Desert Research Institute in 2023. These new measurements of the Hans Tausen 1995 (HT95) ice core, which was provided by collaborators at the University of Copenhagen, were used along with existing ice-core datasets to underpin atmospheric modeling to understand past emissions of black carbon from biomass burning and anthropogenic activities over the past 250 years (Zhang et al., 2024). The HT95 ice core was collected in 1995 and extends to ~3670 BCE.
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- Award ID(s):
- 2102917
- PAR ID:
- 10644605
- Publisher / Repository:
- NSF Arctic Data Center
- Date Published:
- Format(s):
- Medium: X Other: text/xml
- Sponsoring Org:
- National Science Foundation
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