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Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere 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 a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates as well as consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover-change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models forced by observed climate, CO2, and land-cover change (some including nitrogen-carbon interactions). We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2005-2014), EFF was 9.0 ± 0.5 GtC yrg'1, ELUC was 0.9 ± 0.5 GtC yrg'1, GATM was 4.4 ± 0.1 GtC yrg'1, SOCEAN was 2.6 ± 0.5 GtC yrg'1, and SLAND was 3.0 ± 0.8 GtC yrg'1. For the year 2014 alone, EFF grew to 9.8 ± 0.5 GtC yrg'1, 0.6 % above 2013, continuing the growth trend in these emissions, albeit at a slower rate compared to the average growth of 2.2 % yrg'1 that took place during 2005-2014. Also, for 2014, ELUC was 1.1 ± 0.5 GtC yrg'1, GATM was 3.9 ± 0.2 GtC yrg'1, SOCEAN was 2.9 ± 0.5 GtC yrg'1, and SLAND was 4.1 ± 0.9 GtC yrg'1. GATM was lower in 2014 compared to the past decade (2005-2014), reflecting a larger SLAND for that year. The global atmospheric CO2 concentration reached 397.15 ± 0.10 ppm averaged over 2014. For 2015, preliminary data indicate that the growth in EFF will be near or slightly below zero, with a projection of g'0.6 [range of g'1.6 to +0.5] %, based on national emissions projections for China and the USA, and projections of gross domestic product corrected for recent changes in the carbon intensity of the global economy for the rest of the world. From this projection of EFF and assumed constant ELUC for 2015, cumulative emissions of CO2 will reach about 555 ± 55 GtC (2035 ± 205 GtCO2) for 1870-2015, about 75 % from EFF and 25 % from ELUC. This living data update documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this data set (Le Quéré et al., 2015, 2014, 2013). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP-2015).

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.dsr.2006.07.006 Byline: N. Metzl, C. Brunet, A. Jabaud-Jan, A. Poisson, B. Schauer Keywords: Carbon dioxide; Southern Ocean; Air-sea CO.sub.2 fluxes; Seasonality Abstract: The seasonal variability of the carbon dioxide (CO.sub.2) system in the Southern Ocean, south of 50[degrees]S, is analysed from observations obtained in January and August 2000 during OISO cruises conducted in the Indian Antarctic sector. In the seasonal ice zone, SIZ (south of 58[degrees]S), surface ocean CO.sub.2 concentrations are well below equilibrium during austral summer. During this season, when sea-ice is not obstructing gas exchange at the air-sea interface, the oceanic CO.sub.2 sink ranges from -2 to -4mmol/m.sup.2/d in the SIZ. In the permanent open ocean zone, POOZ (50-58[degrees]S), surface oceanic fugacity fCO.sub.2 increases from summer to winter. The seasonal fCO.sub.2 variations (from 10 to 30[mu]atm) are relatively low compared to seasonal amplitudes observed in the subtropics or the subantarctic zones. However, these variations in the POOZ are large enough to cross the atmospheric level from summer to winter. Therefore, this region is neither a permanent CO.sub.2 sink nor a permanent CO.sub.2 source. In the POOZ, air-sea CO.sub.2 fluxes calculated from observations are about -1.1mmol/m.sup.2/d in January (a small sink) and 2.5mmol/m.sup.2/d in August (a source). These estimates obtained for only two periods of the year need to be extrapolated on a monthly scale in order to calculate an integrated air-sea CO.sub.2 flux on an annual basis. For doing this, we use a biogeochemical model that creates annual cycles for nitrate, inorganic carbon, total alkalinity and fCO.sub.2. The changing pattern of ocean CO.sub.2 summer sink and winter source is well reproduced by the model. It is controlled mainly by the balance between summer primary production and winter deep vertical mixing. In the POOZ, the annual air-sea CO.sub.2 flux is about -0.5mol/m.sup.2/yr, which is small compared to previous estimates based on oceanic observations but comparable to the small CO.sub.2 sink deduced from atmospheric inverse methods. For reducing the uncertainties attached to the global ocean CO.sub.2 sink south of the Polar Front the regional results presented here should be synthetized with historical and new observations, especially during winter, in other sectors of the Southern Ocean. Author Affiliation: Laboratoire d'Oceanographie et du Climat: Experimentation et Approches Numeriques, Institut Pierre Simon Laplace, CNRS-UMR 7159, Universite P. et M. Curie, Case 100, 4, place Jussieu-75252 Paris Cedex 5, France Article History: Received 16 August 2005; Revised 14 June 2006; Accepted 14 July 2006