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Published December 2021 | Supplemental Material + Published
Journal Article Open

The Carbon Cycle of Southeast Australia During 2019–2020: Drought, Fires, and Subsequent Recovery

Byrne, B. ORCID icon
Liu, J. ORCID icon
Lee, M. ORCID icon
Yin, Y. ORCID icon
Bowman, K. W. ORCID icon
Miyazaki, K. ORCID icon
Norton, A. J. ORCID icon
Joiner, J. ORCID icon
Pollard, D. F. ORCID icon
Griffith, D. W. T. ORCID icon
Velazco, V. A. ORCID icon
Deutscher, N. M. ORCID icon
Jones, N. B. ORCID icon
Paton-Walsh, C. ORCID icon

Abstract

2019 was the hottest and driest year on record for southeast Australia leading to bushfires of unprecedented extent. Ecosystem carbon losses due to drought and fire are believed to have been substantial, but have not been well quantified. Here, we utilize space-based measurements of trace gases (TROPOspheric Monitoring Instrument XCO, Orbiting Carbon Observatory 2 X_(CO₂)) and up-scaled GPP (FluxSat GPP) to quantify the carbon cycle anomalies resulting from drought and fire in southeast Australia during the 2019–2020 growing season. We find that biomass burning released 113–236 TgC of CO₂ while drought and fire-induced anomalies in net ecosystem exchange reduced growing season carbon uptake by an additional 19–52 TgC of CO₂. These carbon losses were concentrated during the spring and early summer, when hot-dry conditions were most severe. A shift to cooler conditions with above average rainfall during February is found to result in a partial recovery and greening in unburned ecosystems, but not in fire-impacted areas. The net 2019–2020 carbon loss substantially exceeded interannual variations in net uptake over 2010–2019 estimated from top-down constraints (∼5σ anomaly), and exceeded Australia's annual fossil fuel emissions (∼104 TgC year⁻¹). Top-down constraints show that the regional carbon budget is strongly regulated by climate variability, and suggest that cool-wet conditions are required for a rapid recovery of carbon stocks. This has implications for the regional carbon budget as more frequent climate-change-driven heat and drought events may increase the frequency of fire events and the recovery time of ecosystems, threatening the carbon stocks of the region.

Additional Information

© 2021 Jet Propulsion Laboratory, California Institute of Technology. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Issue Online: 09 December 2021. Version of Record online: 09 December 2021. Manuscript accepted: 18 October 2021. Manuscript revised: 08 October 2021. Manuscript received: 01 May 2021. B. Byrne was supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, administered by Universities Space Research Association under contract with the NASA. B. Byrne and J. Liu were supported by the NASA OCO2/3 science team program NNH17ZDA001N-OCO2. K. W. Bowman was supported by the NASA Carbon Monitoring System (CMS) project (NNH16ZDA001N-CMS). J. Joiner was supported by the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) and Arctic Boreal Vulnerability Experiment (ABoVE) programs. Y. Yin was partially supported by the NASA ECOSTRESS Science Team Project (80NSSC20K0078). The research carried out at the Jet Propulsion Laboratory, California Institute of Technology, was under a contract with the National Aeronautics and Space Administration. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at the Ames Research Center. ODIAC project is supported by the Greenhouse Gas Observing SATellite (GOSAT) project, National Institute for Environmental Studies (NIES), Japan. Wollongong TCCON measurements over the period of this study are supported by the Australian Research Council (ARC) grants DP160101598 and LE0668470, while N. M. Deutscher was supported by an ARC Future Fellowship, FT180100327. The authors would like to thank Tom Oda for guidance on fossil fuel statistics. The authors also thank the editor and reviewers for valuable comments that greatly improved this study. The authors declare no conflicts of interest relevant to this study. Data Availability Statement. The gridded daily estimates of ΔNEE and biomass burning emissions from this study can be downloaded from (https://doi.org/10.48577/jpl.rrk6-7453). GFED data were downloaded from https://www.globalfiredata.org/. GFAS data were downloaded from https://apps.ecmwf.int/datasets/. GFAS is generated using Copernicus Atmosphere Monitoring Service Information 2020, neither the European Commission nor ECMWF is responsible for any use that may be made of the information it contains. TCCON data were obtained from the TCCON Data Archive, hosted by CaltechDATA (https://tccondata.org). We downloaded version 10 of the ACOS OCO-2 lite files from the CO₂ Virtual Science Data Environment (https://co2.jpl.nasa.gov/). OCO-2 data were produced by the OCO-2 project at the Jet Propulsion Laboratory, California Institute of Technology, and obtained from the OCO-2 data archive maintained at the NASA Goddard Earth Science Data and Information Services Center. FluxSat data were downloaded from https://avdc.gsfc.nasa.gov/pub/tmp/FluxSat_GPP/. MODIS land cover data was downloaded from the EOSDIS Land Processes DAAC. ETOPO1 elevation data was downloaded from https://www.ngdc.noaa.gov. ERA5-Land data are obtained from the Climate Data Store (https://cds.climate.copernicus.eu). TROPOMI CO data were downloaded from http://www.tropomi.eu/data-products/carbon-monoxide. CrIS CO is provided by the NASA TRoposperhic Ozone and its Precursors from Earth System Sounding (TROPESS) and available from https://tes.jpl.nasa.gov. MODIS NIRv was calculated from MODIS NBAR measurements (MCD43A4), which were downloaded from the LP DAAC. TROPOMI L2 SIF data were downloaded from ftp://fluo.gps.caltech.edu/data/tropomi/ungridded/SIF740nm. OCO-2 L2 SIF data are available from the GES DISC (https://disc.gsfc.nasa.gov). BHD CO/CO₂ and LAU CO data were downloaded from the World Data Centre for Greenhouse Gases (https://gaw.kishou.go.jp/). LAU CO₂ data were obtained from the site PIs. Paul Krummel, Ray Langenfelds, and Zoe Loh are thanked for supplying the CGO CO/CO2 data. Australia fossil fuel combustion statistics were downloaded IEA's CO₂ Emissions from Fuel Combustion Highlights: https://www.iea.org/data-and-statistics/data-product/co2-emissions-from-fuel-combustion-highlights

Attached Files

Published - 2021AV000469.pdf

Supplemental Material - 2021av000469-sup-0001-supporting_information-s01.pdf

Supplemental Material - 2021av000469-sup-0002-original_version_of_manuscript-s02.pdf

Supplemental Material - 2021av000469-sup-0003-peer_review_history-s03.pdf

Supplemental Material - 2021av000469-sup-0004-_first_revision_of_manuscript-s04.pdf

Supplemental Material - 2021av000469-sup-0005-second_revision_of_manuscript__accepted_-s05.pdf

Supplemental Material - 2021av000469-sup-0006-author_response_to_peer_review_comments-s06.pdf

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2021av000469-sup-0002-original_version_of_manuscript-s02.pdf

Additional details

Identifiers Related works Funding Dates
Created:
August 22, 2023
Modified:
October 23, 2023