27 Jul 2022
27 Jul 2022
Status: this preprint is currently under review for the journal BG.

Carbon emissions and radiative forcings from tundra wildfires in the Yukon-Kuskokwim River Delta, Alaska

Michael Moubarak1, Seeta Sistla2, Stefano Potter3, Susan M. Natali3,, and Brendan M. Rogers3, Michael Moubarak et al.
  • 1Department of Biology, Hamilton College, Clinton, NY 13323, United States
  • 2Department of Natural Resources and Environmental Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, United States
  • 3Woodwell Climate Research Center, Falmouth, MA 02540, United States
  • Equal last authorship

Abstract. Tundra environments are experiencing elevated levels of wildfire, and the frequency is expected to keep increasing due to accelerating climate change in the Arctic. Tundra wildfires can release globally significant amounts of greenhouse gasses that influence the Earth’s radiative balance. Here we develop a novel method for estimating carbon loss and the resulting radiative forcings of gaseous and aerosol emissions from 2015 tundra wildfires in the Yukon-Kuskokwim Delta (YKD), AK. We paired burn depth measurements using two vegetative reference points that survived the fire event —Sphagnum fuscum and Dicranum spp.— with measurements of local organic matter and soil carbon properties to estimate total ecosystem organic matter and carbon loss. We used remotely-sensed data of fire severity from Landsat 8 to scale our measured losses to the entire fire-affected area, with an estimated total loss of 2.04 Tg of organic matter and 0.91 Tg of carbon, and an average loss of 3.76 kg m-2 of organic matter and 1.68 kg m-2 of carbon in the 2015 YKD wildfires. To demonstrate the impact of these fires on Earth’s radiation budget, we developed a simple but comprehensive framework to estimate the radiative forcing from Arctic wildfires. We synthesized existing research on the lifetime and radiative forcings of gaseous and aerosol emissions of CO2, N2O, CH4, O3 and its precursors, and fire aerosols. The model shows a net positive cumulative mean radiative forcing of 3.67 W m-2 using RCP 4.5 and 3.37 W m-2 using RCP 8.5 at 80 years post-fire, which was dominated by CO2 emissions. Our results highlight the climate impact of tundra wildfires, which positively reinforce climate warming and increased fire frequency through the radiative forcings of their gaseous emissions.

Michael Moubarak et al.

Status: open (until 07 Sep 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Michael Moubarak et al.

Data sets

Yukon-Kuskokwim River Delta 2015 fire burn depth measurements and unburned soil and vegetation organic matter and carbon content collected in 2019 Michael Moubarak, Seeta Sistla, Susan M. Natali

Model code and software

Radiative forcings of gaseous emissions Michael Moubarak

Michael Moubarak et al.


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Short summary
Tundra wildfires are increasing in frequency and severity with climate change. We show using a combination of field measurements and computational modeling that tundra wildfires result in a positive feedback to climate change by emitting significant amounts of long-lived greenhouse gasses. With these effects, attention to tundra fires is necessary for mitigating climate change.