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Publication - Dr Jo House

    Global Carbon Budget 2015

    Citation

    Le Quéré, C, Moriarty, R, Andrew, RM, Canadell, JG, Sitch, S, Korsbakken, JI, Friedlingstein, P, Peters, GP, Andres, RJ, Boden, TA, Houghton, RA, House, JI, Keeling, RF, Tans, P, Arneth, A, Bakker, DCE, Barbero, L, Bopp, L, Chang, J, Chevallier, F, Chini, LP, Ciais, P, Fader, M, Feely, RA, Gkritzalis, T, Harris, I, Hauck, J, Ilyina, T, Jain, AK, Kato, E, Kitidis, V, Goldewijk, KK, Koven, C, Landschützer, P, Lauvset, SK, Lefèvre, N, Lenton, A, Lima, ID, Metzl, N, Millero, F & others 2015, ‘Global Carbon Budget 2015’. Earth System Science Data, vol 7., pp. 349-396

    Abstract

    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 yr−1, ELUC was 0.9 ± 0.5 GtC yr−1, GATM was 4.4 ± 0.1 GtC yr−1, SOCEAN was 2.6 ± 0.5 GtC yr−1, and SLAND was 3.0 ± 0.8 GtC yr−1. For the year 2014 alone, EFF grew to 9.8 ± 0.5 GtC yr−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 % yr−1 that took place during 2005–2014. Also, for 2014, ELUC was 1.1 ± 0.5 GtC yr−1, GATM was 3.9 ± 0.2 GtC yr−1, SOCEAN was 2.9 ± 0.5 GtC yr−1, and SLAND was 4.1 ± 0.9 GtC yr−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 −0.6 [range
    of −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).

    Full details in the University publications repository