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Global carbon budget 2018

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Le Quere, C and Andrew, RM and Friedlingstein, P and Sitch, S and Hauck, J and Pongratz, J and Pickers, PA and Korsbakken, JI and Peters, GP and Canadell, JG and Arneth, A and Arora, VK and Barbero, L and Bastos, A and Bopp, L and Chevallier, F and Chini, LP and Ciais, P and Doney, SC and Gkritzalis, T and Goll, D and Harris, I and Haverd, V and Hoffman, FM and Hoppema, M and Houghton, R and Hurtt, G and Ilyina, T and Jain, A and Johannessen, T and Jones, C and Kato, E and Keeling, R and Klein Goldewijk, K and Landschutzer, P and Lefevre, N and Lienert, S and Liu, Z and Lombardozzi, D and Metzl, N and Munro, DR and Nabel, JEMS and Nakaoka, SI and Neill, C and Olsen, A and Ono, T and Patra, P and Peregon, A and Peters, W and Peylin, P and Pfeil, B and Pierrot, D and Poulter, B and Rehder, G and Resplandy, L and Robertson, E and Rocher, M and Rodenbeck, C and Schuster, U and Skjelvan, I and Seferian, R and Steinhoff, T and Sutton, A and Tans, P and Tian, H and Tilbrook, B and Tubiello, F and van der Laan-Luijkx, IT and van der Werf, GR and Viovy, N and Walker, A and Wiltshire, A and Wright, R and Zaehle, S and Zheng, B, Global carbon budget 2018, Earth System Science Data, 10, (4) pp. 2141-2194. ISSN 1866-3508 (2018) [Refereed Article]


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© Author(s) 2018. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) http://creativecommons.org/licenses/by/4.0/

DOI: doi:10.5194/essd-10-2141-2018

Abstract

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere – the "global carbon budget" – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFF) are based on energy statistics and cement production data, while emissions from land use and land-use change (ELUC), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2008–2017), EFF was 9.4±0.5 GtC yr−1, ELUC 1.5±0.7 GtC yr−1, GATM 4.7±0.02 GtC yr−1, SOCEAN 2.4±0.5 GtC yr−1, and SLAND 3.2±0.8 GtC yr−1, with a budget imbalance BIM of 0.5 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For the year 2017 alone, the growth in EFF was about 1.6 % and emissions increased to 9.9±0.5 GtC yr−1. Also for 2017, ELUC was 1.4±0.7 GtC yr−1, GATM was 4.6±0.2 GtC yr−1, SOCEAN was 2.5±0.5 GtC yr−1, and SLAND was 3.8±0.8 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 405.0±0.1 ppm averaged over 2017. For 2018, preliminary data for the first 6–9 months indicate a renewed growth in EFF of +2.7 % (range of 1.8 % to 3.7 %) based on national emission projections for China, the US, the EU, and India and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. The analysis presented here shows that the mean and trend in the five components of the global carbon budget are consistently estimated over the period of 1959–2017, but discrepancies of up to 1 GtC yr−1 persist for the representation of semi-decadal variability in CO2 fluxes. A detailed comparison among individual estimates and the introduction of a broad range of observations show (1) no consensus in the mean and trend in land-use change emissions, (2) a persistent low agreement among the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent underestimation of the CO2 variability by ocean models, originating outside the tropics. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018, 2016, 2015a, b, 2014, 2013). All results presented here can be downloaded from https://doi.org/10.18160/GCP-2018.

Item Details

Item Type:Refereed Article
Keywords:global carbon budget, CO2 emissions, carbon cycle, climate change
Research Division:Earth Sciences
Research Group:Atmospheric Sciences
Research Field:Climate Change Processes
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Change Models
UTAS Author:Tilbrook, B (Dr Bronte Tilbrook)
ID Code:132051
Year Published:2018
Web of Science® Times Cited:54
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2019-04-17
Last Modified:2019-05-06
Downloads:3 View Download Statistics

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