*Input contributed by Ben Poulter (NASA Goddard), with excerpts cross-posted from NOAA.gov and globalcarbonproject.org*

The 2020 Global Carbon Budget was released by the Global Carbon Project team of scientists in December 2020. The annual budget is an assessment of the sources of carbon dioxide emissions from fossil fuels and deforestation, the growth of CO₂ in the atmosphere, and the uptake from terrestrial and ocean processes. The newest edition, uses a wide range of global observational datasets from in-situ monitoring and remote sensing, combined with data from process-models, the Global Carbon Project provides a multi-decadal perspective on the carbon cycle up to the most recent full calendar year, 2019, also providing a forecast for the following year, 2020.

Summarizing the major findings from this budget, Dr. Ben Poulter from NASA Goddard, one of the members of the the team, stated, 'The economic effects of COVID19 caused fossil fuel emissions to decrease by 7% in 2020, but we continue to see atmospheric CO₂ concentrations increase, by 2.5 ppm, or about 5.3 PgC. This means that the remaining carbon budget to avoid 1.5 or 2 degrees warming continues to shrink, and that we need to continue to monitor the land, ocean, and atmosphere to understand where fossil fuel CO₂ ends up'.

The U.S. Carbon Cycle Science Program Office has been collaborating with the Global Carbon Project since 2007. The Global Carbon Project is a Global Research Project of Future Earth and a research partner of the World Climate Programme (WCRP). As part of its mandate to promote international cooperation around global change research, the USGCRP coordinates activities with Future Earth and WCRP and contributes to their core funding.

Key Highlights of the 2020 budget:      

-          For 2019, total emissions were 11.5 GtC (Gt=billion tonnes), the growth of CO2 in the atmosphere was 5.4 GtC (or 2.54 ppm), uptake by the oceans was 2.6 GtC and by the land 3.1 GtC.

-          Fossil fuel emissions in 2019 grew by 0.1% over 2018 emissions, distributed among coal (39%), oil (34%), natural gas (21%), cement (4%) and other sources (1.5%).

-          Atmospheric carbon dioxide concentrations in 2019 reached 409.9 ppm.

-          The 2019 land sink (3.1 GtC) was slightly lower than the decadal mean of 3.4 GtC.

-          The budget imbalance, an indicator of the budget uncertainty, grew to 0.3 GtC from the decadal mean of 0.1 GtC, meaning that unexplained sources of interannual variability in sources or sinks remain.

-          Because of COVID-19 related economic changes, the forecast for 2020 emissions expects approximately 7% decline in global fossil fuel emissions. But this depends on the recovery trajectory followed by industrialized nations.

'The Global Carbon Budget is produced by more than 80 researchers working from universities and research institutions in 15 countries working under the umbrella of the Global Carbon Project. This edition of the annual update includes contributions from multiple organizations and research groups around the world that generate original measurements and data used to complete the global carbon budget (NOAA 2020)', including many U.S. scientists and the work of U.S. Carbon Cycle Science Program or Carbon Cycle Interagency Working Group (CCIWG) member agencies and departments.

For instance, many NASA observations and models were used to formulate the 2020 budget. These include:

-          MODIS (Aqua/Terra)

-          GFED (fire emissions and deforestation fires)

-          LPJ (land surface carbon exchange)

-          Landsat (in LUHv2)

-          LUHv2 (land-cover change)

-          CASA (land surface carbon exchange)

-          ODIAC (surface fossil fuel emissions)

-          MERRA-2 (GMAO Reanalysis)

-          CGADIP (NASA contribution to aircraft CO2 concentrations)

-          OCO-2 XCO2

-         Different science teams such as those of the NASA Carbon Monitoring System (CMS), Interdisciplinary Sciences, OCO-2 Science, ABOVE, MODIS Science Teams. NASA Earth Science programs such as Land Cover Change, Carbon Cycle and Ecosystems Office, Airborne Sciences provide funding mechanisms for this work to be carried out.

'NOAA research efforts also contributed significantly to this global assessment. GOMO provided funding support for ocean carbon observation data collected by researchers at NOAA’s Atlantic Oceanographic and Meteorological Laboratory and Pacific Marine Environmental Laboratory. NOAA’s Global Monitoring Laboratory provided atmospheric carbon dioxide concentration data. Contributors to the 2020 paper include Simone Alin (NOAA-PMEL), David R. Munro (NOAA-GML/CIRES), Kevin O’Brien (NOAA-PMEL/CICOES) Denis Pierrot (NOAA-AOML), Adrienne Sutton (NOAA-PMEL), Pieter Tans (NOAA-GML), Rik Wanninkhof (NOAA-AOML), and Nick Bates (BIOS). NOAA’s Global Greenhouse Gas Reference Network, part of the Global Monitoring Lab provides atmospheric data for the Global Carbon Budget. The 2020 data show that the average rate of increase of CO₂ in the atmosphere has been higher in the last decade (2010-2019) than at any other time in recorded history....NOAA’s Global Ocean Monitoring and Observing Program (GOMO) provides funding support for ocean carbon observation data that is used to determine the ocean sink, or amount of carbon absorbed by the ocean. A global collaboration called SOCAT (Surface Ocean CO₂ Atlas) collects all surface water CO₂ levels annually and is the cornerstone to quantify ocean CO₂ uptake that is critical to the Global Carbon Budget. GOMO funded investigators provide over half the data for the SOCAT database, which is comprised of over 27 million observations spanning over six decades. In response to the atmospheric CO₂ increase, the uptake by the ocean has increased as well; ocean CO₂ uptake is influenced by oceanic processes and varies seasonally and decadally. The uptake has led to increasing levels of surface ocean acidification. The release of this year’s Global Carbon Budget comes ahead of the fifth anniversary of the adoption of the UN Paris Climate Agreement, which aims to reduce the emission of greenhouse gases to limit global warming. Cuts of around 0.3 to 0.6 Gt C (or 1 to 2 Gt of CO₂) are needed each year on average between 2020 and 2030 to limit climate change in line with its goals. The magnitude of emission reductions, its verification, and impact on climate change depends, to a significant extent, on the ocean and land continuing to sequester CO₂.  This requires a robust atmospheric, ocean and terrestrial CO₂ observing system (NOAA, 2020).'

Follow the highlights and the links below for details. Also see the updated Global Carbon Atlas.

The primary reference for Carbon Budget 2020 is:

Global Carbon Budget 2020, by Pierre Friedlingstein, Michael O'Sullivan, Matthew W. Jones, Robbie M. Andrew, Judith Hauck, Are Olsen, Glen P. Peters, Wouter Peters, Julia Pongratz, Stephen Sitch, Corinne Le Quéré, Josep G. Canadell, Philippe Ciais, Robert B. Jackson, Simone Alin, Luiz E. O. C. Aragão, Almut Arneth, Vivek Arora, Nicholas R. Bates, Meike Becker, Alice Benoit-Cattin, Henry C. Bittig, Laurent Bopp, Selma Bultan, Naveen Chandra, Frédéric Chevallier, Louise P. Chini, Wiley Evans, Liesbeth Florentie, Piers M. Forster, Thomas Gasser, Marion Gehlen, Dennis Gilfillan, Thanos Gkritzalis, Luke Gregor, Nicolas Gruber, Ian Harris, Kerstin Hartung, Vanessa Haverd, Richard A. Houghton, Tatiana Ilyina, Atul K. Jain, Emilie Joetzjer, Koji Kadono, Etsushi Kato, Vassilis Kitidis, Jan Ivar Korsbakken, Peter Landschützer, Nathalie Lefèvre, Andrew Lenton, Sebastian Lienert, Zhu Liu, Danica Lombardozzi, Gregg Marland, Nicolas Metzl, David R. Munro, Julia E. M. S. Nabel, Shin-Ichiro Nakaoka, Yosuke Niwa, Kevin O'Brien, Tsuneo Ono, Paul I. Palmer, Denis Pierrot, Benjamin Poulter, Laure Resplandy, Eddy Robertson, Christian Rödenbeck, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Adam J. P. Smith, Adrienne J. Sutton, Toste Tanhua, Pieter P. Tans, Hanqin Tian, Bronte Tilbrook, Guido van der Werf, Nicolas Vuichard, Anthony P. Walker, Rik Wanninkhof, Andrew J. Watson, David Willis, Andrew J. Wiltshire, Wenping Yuan, Xu Yue, and Sönke Zaehle (2020), Earth System Science Data, 12, 3269–3340, 2020, DOI: 10.5194/essd-12-3269-2020.

Other Citation instruction: Global Carbon Project (2020) Carbon budget and trends 2020. [www.globalcarbonproject.org/carbonbudget] published on 11 December 2020, along with any other original peer-reviewed papers and data sources as appropriate.

Other papers relevant to the Carbon Budget 2020:

Temporary reduction in daily global CO₂ emissions during the COVID-19 forced confinement by Corinne Le Quéré, Robert B. Jackson, Matthew W. Jones, Adam J. P. Smith, Sam Abernethy, Robbie M. Andrew, Anthony J. De-Gol, David R. Willis, Yuli Shan, Josep G. Canadell, Pierre Friedlingstein, Felix Creutzig & Glen P. Peters (2020), Nature Climate Change, 2020. DOI: 10.1038/s41558-020-0797-x.

Current and future global climate impacts resulting from COVID-19 by Piers M. Forster, Harriet I. Forster, Mat J. Evans, Matthew J. Gidden, Chris D. Jones, Christoph A. Keller, Robin D. Lamboll, Corinne Le Quéré, Joeri Rogelj, Deborah Rosen, Carl-Friedrich Schleussner, Thomas B. Richardson, Christopher J. Smith & Steven T. Turnock (2020), Nature Climate Change, 2020. DOI: 10.1038/s41558-020-0883-0.

Near-real-time monitoring of global CO₂ emissions reveals the effects of the COVID-19 pandemic by Zhu Liu, Philippe Ciais, Zhu Deng, Ruixue Lei, Steven J. Davis, Sha Feng, Bo Zheng, Duo Cui, Xinyu Dou, Biqing Zhu, Rui Guo, Piyu Ke, Taochun Sun, Chenxi Lu, Pan He, Yuan Wang, Xu Yue, Yilong Wang, Yadong Lei, Hao Zhou, Zhaonan Cai, Yuhui Wu, Runtao Guo, Tingxuan Han, Jinjun Xue, Olivier Boucher, Eulalie Boucher, Frédéric Chevallier, Katsumasa Tanaka, Yiming Wei, Haiwang Zhong, Chongqing Kang, Ning Zhang, Bin Chen, Fengming Xi, Miaomiao Liu, François-Marie Bréon, Yonglong Lu, Qiang Zhang, Dabo Guan, Peng Gong, Daniel M. Kammen, Kebin He & Hans Joachim Schellnhuber (2020), Nature Communications, 2020. DOI: 10.1038/s41467-020-18922-7.

Timely estimates of India's annual and monthly fossil CO₂ emissions by Robbie M. Andrew (2020), Earth System Science Data, 2020. DOI: 10.5194/essd-12-2411-2020.

Access to paper

• Friedlingstein et al. ESSD paper is available from:
  https://doi.org/10.5194/essd-12-3269-2020.

For data sources refer to Data.

Contributors to Global Carbon Budget 2020

• Pierre Friedlingstein (College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK and Laboratoire de Météorologie Dynamique, Institut Pierre-Simon Laplace, CNRS-ENS-UPMC-X, Département de Géosciences, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France)
• Michael O'Sullivan (Laboratoire de Météorologie Dynamique, Institut Pierre-Simon Laplace, CNRS-ENS-UPMC-X, Département de Géosciences, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France)
• Matthew W. Jones (Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK)
• Robbie M. Andrew (CICERO Center for International Climate Research, Oslo 0349, Norway)
• Judith Hauck (Alfred-Wegener-Institut Helmholtz-Zentum für Polar- und Meeresforschung, Postfach 120161, 27515 Bremerhaven, Germany)
• Are Olsen (Geophysical Institute, University of Bergen, Bergen, Norway and Bjerknes Centre for Climate Research, Bergen, Norway)
• Glen P. Peters (CICERO Center for International Climate Research, Oslo 0349, Norway)
• Wouter Peters (Wageningen University, Environmental Sciences Group, P.O. Box 47, 6700 AA, Wageningen, the Netherlands and University of Groningen, Centre for Isotope Research, 9747 AG, Groningen, the Netherlands)
• Julia Pongratz (Ludwig-Maximilians-Universität Munich, Luisenstr. 37, 80333 München, Germany and Max Planck Institute for Meteorology, 20146 Hamburg, Germany)
• Stephen Sitch (College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK)
• Corinne Le Quéré (Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK)
• Josep G. Canadell (CSIRO Oceans and Atmosphere, Canberra, ACT 2601, Australia)
• Philippe Ciais (Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91198 Gif-sur-Yvette, France)
• Robert B. Jackson (Department of Earth System Science, Woods Institute for the Environment, and Precourt Institute for Energy, Stanford University, Stanford, CA 94305-2210, USA)
• Simone Alin (National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory (NOAA/PMEL), 7600 Sand Point Way NE, Seattle, WA 98115, USA)
• Luiz E. O. C. Aragão (Remote Sensing Division, National Institute for Space Research, São José dos Campos, Brazil and College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK)
• Almut Arneth (Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research/Atmospheric Environmental Research, 82467 Garmisch-Partenkirchen, Germany)
• Vivek Arora (Canadian Centre for Climate Modelling and Analysis, Climate Research Division, Environment and Climate Change Canada, Victoria, BC, Canada)
• Nicholas R. Bates (Bermuda Institute of Ocean Sciences (BIOS), 17 Biological Lane, St. Georges, GE01, Bermuda and Department of Ocean and Earth Science, University of Southampton, European Way, Southampton SO14 3ZH, UK)
• Meike Becker (Geophysical Institute, University of Bergen, Bergen, Norway and Bjerknes Centre for Climate Research, Bergen, Norway)
• Alice Benoit-Cattin (Marine and Freshwater Research Institute, Fornubudir 5, 220 Hafnarfjordur, Iceland)
• Henry C. Bittig (Leibniz Institute for Baltic Sea Research Warnemuende (IOW), Seestrasse 15, 18119 Rostock, Germany)
• Laurent Bopp (Laboratoire de Météorologie Dynamique/Institut Pierre-Simon Laplace, CNRS, Ecole Normale Supérieure/Université PSL, Sorbonne Université, Ecole Polytechnique, Paris, France)
• Selma Bultan (Ludwig-Maximilians-Universität Munich, Luisenstr. 37, 80333 München, Germany)
• Naveen Chandra (Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, 236-0001, Japan and Center for Global Environmental Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan)
• Frédéric Chevallier (Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91198 Gif-sur-Yvette, France)
• Louise P. Chini (Department of Geographical Sciences, University of Maryland, College Park, MD 20742, USA)
• Wiley Evans (Hakai Institute, Heriot Bay, BC, Canada)
• Liesbeth Florentie (Wageningen University, Environmental Sciences Group, P.O. Box 47, 6700 AA, Wageningen, the Netherlands)
• Piers M. Forster (Priestley International Centre for Climate, University of Leeds, Leeds LS2 9JT, UK)
• Thomas Gasser (International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1 2361 Laxenburg, Austria)
• Marion Gehlen (Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91198 Gif-sur-Yvette, France)
• Dennis Gilfillan (Research Institute for Environment, Energy, and Economics, Appalachian State University, Boone, NC 28608, USA)
• Thanos Gkritzalis (Flanders Marine Institute (VLIZ), InnovOceanSite, Wandelaarkaai 7, 8400 Ostend, Belgium)
• Luke Gregor (Environmental Physics Group, ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics and Center for Climate Systems Modeling (C2SM), Zurich, Switzerland)
• Nicolas Gruber (Environmental Physics Group, ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics and Center for Climate Systems Modeling (C2SM), Zurich, Switzerland)
• Ian Harris (NCAS-Climate, Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK)
• Kerstin Hartung (Ludwig-Maximilians-Universität Munich, Luisenstr. 37, 80333 München, Germany and now at Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany)
• Vanessa Haverd (CSIRO Oceans and Atmosphere, Canberra, ACT 2601, Australia)
• Richard A. Houghton (Woods Hole Research Center (WHRC), Falmouth, MA 02540, USA)
• Tatiana Ilyina (Max Planck Institute for Meteorology, 20146 Hamburg, Germany)
• Atul K. Jain (Department of Atmospheric Sciences, University of Illinois, Urbana, IL 61821, USA)
• Emilie Joetzjer (CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France)
• Koji Kadono (Japan Meteorological Agency, 1-3-4 Otemachi, Chiyoda-Ku, Tokyo 100-8122, Japan)
• Etsushi Kato (Institute of Applied Energy (IAE), Minato-ku, Tokyo 105-0003, Japan)
• Vassilis Kitidis (Plymouth Marine Laboratory (PML), Plymouth, PL13DH, United Kingdom)
• Jan Ivar Korsbakken (CICERO Center for International Climate Research, Oslo 0349, Norway)
• Peter Landschützer (Max Planck Institute for Meteorology, 20146 Hamburg, Germany)
• Nathalie Lefèvre (LOCEAN/IPSL laboratory, Sorbonne Université, CNRS/IRD/MNHN, Paris, France)
• Andrew Lenton (CSIRO Oceans and Atmosphere, Hobart, TAS, Australia)
• Sebastian Lienert (Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland)
• Zhu Liu (Department of Earth System Science, Tsinghua University, Beijing 100084, China)
• Danica Lombardozzi (National Center for Atmospheric Research, Climate and Global Dynamics, Terrestrial Sciences Section, Boulder, CO 80305, USA)
• Gregg Marland (Research Institute for Environment, Energy, and Economics, Appalachian State University, Boone, NC 28608, USA and Department of Geological and Environmental Sciences, Appalachian State University, Boone, NC 28608-2067, USA)
• Nicolas Metzl (LOCEAN/IPSL laboratory, Sorbonne Université, CNRS/IRD/MNHN, Paris, France)
• David R. Munro (Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80305, USA and National Oceanic and Atmospheric Administration/Global Monitoring Laboratory (NOAA/GML), Boulder, CO 80305, USA)
• Julia E. M. S. Nabel (Max Planck Institute for Meteorology, 20146 Hamburg, Germany)
• Shin-Ichiro Nakaoka (Center for Global Environmental Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan)
• Yosuke Niwa (Center for Global Environmental Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan and Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, 305-0052 Japan)
• Kevin O'Brien (Cooperative Institute for Climate, Ocean and Ecosystem Studies (CICOES), University of Washington, Seattle, WA 98105, USA and National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory (NOAA/PMEL), 7600 Sand Point Way NE, Seattle, WA 98115, USA)
• Tsuneo Ono (Japan Fisheries Research and Education Agency, 2-12-4 Fukuura, Kanazawa-Ku, Yokohama 236-8648, Japan)
• Paul I. Palmer (National Centre for Earth Observation, University of Edinburgh, Edinburgh EH9 3FF, UK and School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FF, UK)
• Denis Pierrot (National Oceanic and Atmospheric Administration/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML), Miami, FL 33149, USA)
• Benjamin Poulter (NASA Goddard Space Flight Center, Biospheric Sciences Laboratory, Greenbelt, MD 20771, USA)
• Laure Resplandy (Princeton University, Department of Geosciences and Princeton Environmental Institute, Princeton, NJ 08544, USA)
• Eddy Robertson (Met Office Hadley Centre, FitzRoy Road, Exeter EX1 3PB, UK)
• Christian Rödenbeck (Max Planck Institute for Biogeochemistry, P.O. Box 600164, Hans-Knöll-Str. 10, 07745 Jena, Germany)
• Jörg Schwinger (NORCE Norwegian Research Centre, Jahnebakken 5, 5007 Bergen, Norway and Bjerknes Centre for Climate Research, Bergen, Norway)
• Roland Séférian (CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France)
• Ingunn Skjelvan (NORCE Norwegian Research Centre, Jahnebakken 5, 5007 Bergen, Norway and Bjerknes Centre for Climate Research, Bergen, Norway)
• Adam J. P. Smith (Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK)
• Adrienne J. Sutton (National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory (NOAA/PMEL), 7600 Sand Point Way NE, Seattle, WA 98115, USA)
• Toste Tanhua (GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany)
• Pieter P. Tans (National Oceanic and Atmospheric Administration, Earth System Research Laboratory (NOAA ESRL), Boulder, CO 80305, USA)
• Hanqin Tian (School of Forestry and Wildlife Sciences, Auburn University, 602 Ducan Drive, Auburn, AL 36849, USA)
• Bronte Tilbrook (CSIRO Oceans and Atmosphere, Hobart, TAS, Australia and Australian Antarctic Partnership Program, University of Tasmania, Hobart, Australia)
• Guido van der Werf (Faculty of Science, Vrije Universiteit, Amsterdam, the Netherlands)
• Nicolas Vuichard (Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91198 Gif-sur-Yvette, France)
• Anthony P. Walker (Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Lab, Oak Ridge, TN 37831, USA)
• Rik Wanninkhof (National Oceanic and Atmospheric Administration/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML), Miami, FL 33149, USA)
• Andrew J. Watson (College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK)
• David Willis (University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK)
• Andrew J. Wiltshire (Met Office Hadley Centre, FitzRoy Road, Exeter EX1 3PB, UK)
• Wenping Yuan (School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Zhuhai Key Laboratory of Dynamics Urban Climate and Ecology, Sun Yat-sen University, Zhuhai, Guangdong 510245, China)
• Xu Yue (Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology (NUIST), Nanjing 210044, China)
• Sönke Zaehle (Max Planck Institute for Biogeochemistry, P.O. Box 600164, Hans-Knöll-Str. 10, 07745 Jena, Germany)