Metzl
Nicolas
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Nicolas
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ArticleCorrection to “Using altimetry to help explain patchy changes in hydrographic carbon measurements”(American Geophysical Union, 2009-12-09) Rodgers, Keith B. ; Key, Robert M. ; Gnanadesikan, Anand ; Sarmiento, Jorge L. ; Aumont, Olivier ; Bopp, Laurent ; Doney, Scott C. ; Dunne, John P. ; Glover, David M. ; Ishida, Akio ; Ishii, Masao ; Jacobson, Andrew R. ; Monaco, Claire Lo ; Maier-Reimer, Ernst ; Mercier, Herlé ; Metzl, Nicolas ; Perez, Fiz F. ; Rios, Aida F. ; Wanninkhof, Rik ; Wetzel, Patrick ; Winn, Christopher D. ; Yamanaka, Yasuhiro
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ArticleGlobal carbon budget 2017(Copernicus Publications on behalf of the European Geosciences Union, 2018-03-12) Le Quere, Corinne ; Andrew, Robbie M. ; Friedlingstein, Pierre ; Sitch, Stephen ; Pongratz, Julia ; Manning, Andrew C. ; Korsbakken, Jan Ivar ; Peters, Glen P. ; Canadell, Josep G. ; Jackson, Robert B. ; Boden, Thomas A. ; Tans, Pieter P. ; Andrews, Oliver D. ; Arora, Vivek K. ; Bakker, Dorothee ; Barbero, Leticia ; Becker, Meike ; Betts, Richard A. ; Bopp, Laurent ; Chevallier, Frédéric ; Chini, Louise Parsons ; Ciais, Philippe ; Cosca, Catherine E. ; Cross, Jessica N. ; Currie, Kim I. ; Gasser, Thomas ; Harris, Ian ; Hauck, Judith ; Haverd, Vanessa ; Houghton, Richard A. ; Hunt, Christopher W. ; Hurtt, George ; Ilyina, Tatiana ; Jain, Atul K. ; Kato, Etsushi ; Kautz, Markus ; Keeling, Ralph F. ; Klein Goldewijk, Kees ; Körtzinger, Arne ; Landschützer, Peter ; Lefèvre, Nathalie ; Lenton, Andrew ; Lienert, Sebastian ; Lima, Ivan D. ; Lombardozzi, Danica ; Metzl, Nicolas ; Millero, Frank J. ; Monteiro, Pedro M. S. ; Munro, David R. ; Nabel, Julia E. M. S. ; Nakaoka, Shin-ichiro ; Nojiri, Yukihiro ; Padin, X. Antonio ; Peregon, Anna ; Pfeil, Benjamin ; Pierrot, Denis ; Poulter, Benjamin ; Rehder, Gregor ; Reimer, Janet ; Rödenbeck, Christian ; Schwinger, Jorg ; Séférian, Roland ; Skjelvan, Ingunn ; Stocker, Benjamin D. ; Tian, Hanqin ; Tilbrook, Bronte ; Tubiello, Francesco N. ; van der Laan-Luijkx, Ingrid T. ; van der Werf, Guido R. ; van Heuven, Steven ; Viovy, Nicolas ; Vuichard, Nicolas ; Walker, Anthony P. ; Watson, Andrew J. ; Wiltshire, Andrew J. ; Zaehle, Sonke ; Zhu, DanAccurate 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. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on land-cover change data and bookkeeping models. The global atmospheric CO2 concentration is measured directly and its rate of growth (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 (2007–2016), EFF was 9.4 ± 0.5 GtC yr−1, ELUC 1.3 ± 0.7 GtC yr−1, GATM 4.7 ± 0.1 GtC yr−1, SOCEAN 2.4 ± 0.5 GtC yr−1, and SLAND 3.0 ± 0.8 GtC yr−1, with a budget imbalance BIM of 0.6 GtC yr−1 indicating overestimated emissions and/or underestimated sinks. For year 2016 alone, the growth in EFF was approximately zero and emissions remained at 9.9 ± 0.5 GtC yr−1. Also for 2016, ELUC was 1.3 ± 0.7 GtC yr−1, GATM was 6.1 ± 0.2 GtC yr−1, SOCEAN was 2.6 ± 0.5 GtC yr−1, and SLAND was 2.7 ± 1.0 GtC yr−1, with a small BIM of −0.3 GtC. GATM continued to be higher in 2016 compared to the past decade (2007–2016), reflecting in part the high fossil emissions and the small SLAND consistent with El Niño conditions. The global atmospheric CO2 concentration reached 402.8 ± 0.1 ppm averaged over 2016. For 2017, preliminary data for the first 6–9 months indicate a renewed growth in EFF of +2.0 % (range of 0.8 to 3.0 %) based on national emissions projections for China, USA, and India, and projections of gross domestic product (GDP) corrected for recent changes in the carbon intensity of the economy for the rest of the world. This living data update documents changes in the methods and data sets used in this new global carbon budget compared with previous publications of this data set (Le Quéré et al., 2016, 2015b, a, 2014, 2013). All results presented here can be downloaded from https://doi.org/10.18160/GCP-2017 (GCP, 2017).
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ArticleSea–air CO2 fluxes in the Southern Ocean for the period 1990–2009(Copernicus Publications on behalf of the European Geosciences Union, 2013-06-19) Lenton, Andrew ; Tilbrook, Bronte ; Law, R. M. ; Bakker, Dorothee C. E. ; Doney, Scott C. ; Gruber, Nicolas ; Ishii, Masao ; Hoppema, Mario ; Lovenduski, Nicole S. ; Matear, Richard J. ; McNeil, B. I. ; Metzl, Nicolas ; Mikaloff Fletcher, Sara E. ; Monteiro, Pedro M. S. ; Rodenbeck, C. ; Sweeney, Colm ; Takahashi, TaroThe Southern Ocean (44–75° S) plays a critical role in the global carbon cycle, yet remains one of the most poorly sampled ocean regions. Different approaches have been used to estimate sea–air CO2 fluxes in this region: synthesis of surface ocean observations, ocean biogeochemical models, and atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Southern Ocean sea–air CO2 fluxes between 1990–2009. Using all models and inversions (26), the integrated median annual sea–air CO2 flux of −0.42 ± 0.07 Pg C yr−1 for the 44–75° S region, is consistent with the −0.27 ± 0.13 Pg C yr−1 calculated using surface observations. The circumpolar region south of 58° S has a small net annual flux (model and inversion median: −0.04 ± 0.07 Pg C yr−1 and observations: +0.04 ± 0.02 Pg C yr−1), with most of the net annual flux located in the 44 to 58° S circumpolar band (model and inversion median: −0.36 ± 0.09 Pg C yr−1 and observations: −0.35 ± 0.09 Pg C yr−1). Seasonally, in the 44–58° S region, the median of 5 ocean biogeochemical models captures the observed sea–air CO2 flux seasonal cycle, while the median of 11 atmospheric inversions shows little seasonal change in the net flux. South of 58° S, neither atmospheric inversions nor ocean biogeochemical models reproduce the phase and amplitude of the observed seasonal sea–air CO2 flux, particularly in the Austral Winter. Importantly, no individual atmospheric inversion or ocean biogeochemical model is capable of reproducing both the observed annual mean uptake and the observed seasonal cycle. This raises concerns about projecting future changes in Southern Ocean CO2 fluxes. The median interannual variability from atmospheric inversions and ocean biogeochemical models is substantial in the Southern Ocean; up to 25% of the annual mean flux, with 25% of this interannual variability attributed to the region south of 58° S. Resolving long-term trends is difficult due to the large interannual variability and short time frame (1990–2009) of this study; this is particularly evident from the large spread in trends from inversions and ocean biogeochemical models. Nevertheless, in the period 1990–2009 ocean biogeochemical models do show increasing oceanic uptake consistent with the expected increase of −0.05 Pg C yr−1 decade−1. In contrast, atmospheric inversions suggest little change in the strength of the CO2 sink broadly consistent with the results of Le Quéré et al. (2007).
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ArticleSea–air CO2 fluxes in the Indian Ocean between 1990 and 2009(Copernicus Publications on behalf of the European Geosciences Union, 2013-11-06) Sarma, V. V. S. S. ; Lenton, Andrew ; Law, R. M. ; Metzl, Nicolas ; Patra, Prabir K. ; Doney, Scott C. ; Lima, Ivan D. ; Dlugokencky, Edward J. ; Ramonet, M. ; Valsala, V.The Indian Ocean (44° S–30° N) plays an important role in the global carbon cycle, yet it remains one of the most poorly sampled ocean regions. Several approaches have been used to estimate net sea–air CO2 fluxes in this region: interpolated observations, ocean biogeochemical models, atmospheric and ocean inversions. As part of the RECCAP (REgional Carbon Cycle Assessment and Processes) project, we combine these different approaches to quantify and assess the magnitude and variability in Indian Ocean sea–air CO2 fluxes between 1990 and 2009. Using all of the models and inversions, the median annual mean sea–air CO2 uptake of −0.37 ± 0.06 PgC yr−1 is consistent with the −0.24 ± 0.12 PgC yr−1 calculated from observations. The fluxes from the southern Indian Ocean (18–44° S; −0.43 ± 0.07 PgC yr−1 are similar in magnitude to the annual uptake for the entire Indian Ocean. All models capture the observed pattern of fluxes in the Indian Ocean with the following exceptions: underestimation of upwelling fluxes in the northwestern region (off Oman and Somalia), overestimation in the northeastern region (Bay of Bengal) and underestimation of the CO2 sink in the subtropical convergence zone. These differences were mainly driven by lack of atmospheric CO2 data in atmospheric inversions, and poor simulation of monsoonal currents and freshwater discharge in ocean biogeochemical models. Overall, the models and inversions do capture the phase of the observed seasonality for the entire Indian Ocean but overestimate the magnitude. The predicted sea–air CO2 fluxes by ocean biogeochemical models (OBGMs) respond to seasonal variability with strong phase lags with reference to climatological CO2 flux, whereas the atmospheric inversions predicted an order of magnitude higher seasonal flux than OBGMs. The simulated interannual variability by the OBGMs is weaker than that found by atmospheric inversions. Prediction of such weak interannual variability in CO2 fluxes by atmospheric inversions was mainly caused by a lack of atmospheric data in the Indian Ocean. The OBGM models suggest a small strengthening of the sink over the period 1990–2009 of −0.01 PgC decade−1. This is inconsistent with the observations in the southwestern Indian Ocean that shows the growth rate of oceanic pCO2 was faster than the observed atmospheric CO2 growth, a finding attributed to the trend of the Southern Annular Mode (SAM) during the 1990s.
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ArticleUsing altimetry to help explain patchy changes in hydrographic carbon measurements(American Geophysical Union, 2009-09-18) Rodgers, Keith B. ; Key, Robert M. ; Gnanadesikan, Anand ; Sarmiento, Jorge L. ; Aumont, Olivier ; Bopp, Laurent ; Doney, Scott C. ; Dunne, John P. ; Glover, David M. ; Ishida, Akio ; Ishii, Masao ; Jacobson, Andrew R. ; Monaco, Claire Lo ; Maier-Reimer, Ernst ; Mercier, Herlé ; Metzl, Nicolas ; Perez, Fiz F. ; Rios, Aida F. ; Wanninkhof, Rik ; Wetzel, Patrick ; Winn, Christopher D. ; Yamanaka, YasuhiroHere we use observations and ocean models to identify mechanisms driving large seasonal to interannual variations in dissolved inorganic carbon (DIC) and dissolved oxygen (O2) in the upper ocean. We begin with observations linking variations in upper ocean DIC and O2 inventories with changes in the physical state of the ocean. Models are subsequently used to address the extent to which the relationships derived from short-timescale (6 months to 2 years) repeat measurements are representative of variations over larger spatial and temporal scales. The main new result is that convergence and divergence (column stretching) attributed to baroclinic Rossby waves can make a first-order contribution to DIC and O2 variability in the upper ocean. This results in a close correspondence between natural variations in DIC and O2 column inventory variations and sea surface height (SSH) variations over much of the ocean. Oceanic Rossby wave activity is an intrinsic part of the natural variability in the climate system and is elevated even in the absence of significant interannual variability in climate mode indices. The close correspondence between SSH and both DIC and O2 column inventories for many regions suggests that SSH changes (inferred from satellite altimetry) may prove useful in reducing uncertainty in separating natural and anthropogenic DIC signals (using measurements from Climate Variability and Predictability's CO2/Repeat Hydrography program).
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ArticleGlobal Carbon Budget 2016(Copernicus Publications, 2016-11-14) Le Quere, Corinne ; Andrew, Robbie M. ; Canadell, Josep G. ; Sitch, Stephen ; Korsbakken, Jan Ivar ; Peters, Glen P. ; Manning, Andrew C. ; Boden, Thomas A. ; Tans, Pieter P. ; Houghton, Richard A. ; Keeling, Ralph F. ; Alin, Simone R. ; Andrews, Oliver D. ; Anthoni, Peter ; Barbero, Leticia ; Bopp, Laurent ; Chevallier, Frédéric ; Chini, Louise Parsons ; Ciais, Philippe ; Currie, Kim I. ; Delire, Christine ; Doney, Scott C. ; Friedlingstein, Pierre ; Gkritzalis, Thanos ; Harris, Ian ; Hauck, Judith ; Haverd, Vanessa ; Hoppema, Mario ; Klein Goldewijk, Kees ; Jain, Atul K. ; Kato, Etsushi ; Körtzinger, Arne ; Landschützer, Peter ; Lefèvre, Nathalie ; Lenton, Andrew ; Lienert, Sebastian ; Lombardozzi, Danica ; Melton, Joe R. ; Metzl, Nicolas ; Millero, Frank J. ; Monteiro, Pedro M. S. ; Munro, David R. ; Nabel, Julia E. M. S. ; Nakaoka, Shin-ichiro ; O'Brien, Kevin ; Olsen, Are ; Omar, Abdirahman M. ; Ono, Tsuneo ; Pierrot, Denis ; Poulter, Benjamin ; Rödenbeck, Christian ; Salisbury, Joseph E. ; Schuster, Ute ; Schwinger, Jorg ; Séférian, Roland ; Skjelvan, Ingunn ; Stocker, Benjamin D. ; Sutton, Adrienne J. ; Takahashi, Taro ; Tian, Hanqin ; Tilbrook, Bronte ; van der Laan-Luijkx, Ingrid ; van der Werf, Guido R. ; Viovy, Nicolas ; Walker, Anthony P. ; Wiltshire, Andrew J. ; Zaehle, SonkeAccurate 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 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 and 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, respectively, 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. 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 (2006–2015), EFF was 9.3 ± 0.5 GtC yr−1, ELUC 1.0 ± 0.5 GtC yr−1, GATM 4.5 ± 0.1 GtC yr−1, SOCEAN 2.6 ± 0.5 GtC yr−1, and SLAND 3.1 ± 0.9 GtC yr−1. For year 2015 alone, the growth in EFF was approximately zero and emissions remained at 9.9 ± 0.5 GtC yr−1, showing a slowdown in growth of these emissions compared to the average growth of 1.8 % yr−1 that took place during 2006–2015. Also, for 2015, ELUC was 1.3 ± 0.5 GtC yr−1, GATM was 6.3 ± 0.2 GtC yr−1, SOCEAN was 3.0 ± 0.5 GtC yr−1, and SLAND was 1.9 ± 0.9 GtC yr−1. GATM was higher in 2015 compared to the past decade (2006–2015), reflecting a smaller SLAND for that year. The global atmospheric CO2 concentration reached 399.4 ± 0.1 ppm averaged over 2015. For 2016, preliminary data indicate the continuation of low growth in EFF with +0.2 % (range of −1.0 to +1.8 %) based on national emissions projections for China and USA, and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. In spite of the low growth of EFF in 2016, the growth rate in atmospheric CO2 concentration is expected to be relatively high because of the persistence of the smaller residual terrestrial sink (SLAND) in response to El Niño conditions of 2015–2016. From this projection of EFF and assumed constant ELUC for 2016, cumulative emissions of CO2 will reach 565 ± 55 GtC (2075 ± 205 GtCO2) for 1870–2016, 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., 2015b, a, 2014, 2013). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP_2016).
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ArticleGlobal Carbon Budget 2015(Copernicus Publications, 2015-12-07) Le Quere, Corinne ; Moriarty, Roisin ; Andrew, Robbie M. ; Canadell, Josep G. ; Sitch, Stephen ; Korsbakken, Jan Ivar ; Friedlingstein, Pierre ; Peters, Glen P. ; Andres, Robert J. ; Boden, Thomas A. ; Houghton, Richard A. ; House, Jo I. ; Keeling, Ralph F. ; Tans, Pieter P. ; Arneth, Almut ; Bakker, Dorothee C. E. ; Barbero, Leticia ; Bopp, Laurent ; Chang, J. ; Chevallier, Frédéric ; Chini, Louise Parsons ; Ciais, Philippe ; Fader, Marianela ; Feely, Richard A. ; Gkritzalis, Thanos ; Harris, Ian ; Hauck, Judith ; Ilyina, Tatiana ; Jain, Atul K. ; Kato, Etsushi ; Kitidis, Vassilis ; Klein Goldewijk, Kees ; Koven, Charles ; Landschutzer, Peter ; Lauvset, Siv K. ; Lefevre, N. ; Lenton, Andrew ; Lima, Ivan D. ; Metzl, Nicolas ; Millero, Frank J. ; Munro, David R. ; Murata, Akihiko ; Nabel, Julia E. M. S. ; Nakaoka, Shin-ichiro ; Nojiri, Yukihiro ; O'Brien, Kevin ; Olsen, Are ; Ono, Tsuneo ; Perez, Fiz F. ; Pfeil, Benjamin ; Pierrot, Denis ; Poulter, Benjamin ; Rehder, Gregor ; Rodenbeck, C. ; Saito, Shu ; Schuster, Ute ; Schwinger, Jorg ; Seferian, Roland ; Steinhoff, Tobias ; Stocker, Benjamin D. ; Sutton, Adrienne J. ; Takahashi, Taro ; Tilbrook, Bronte ; van der Laan-Luijkx, I. T. ; van der Werf, Guido R. ; van Heuven, Steven ; Vandemark, Douglas ; Viovy, Nicolas ; Wiltshire, Andrew J. ; Zaehle, Sonke ; Zeng, NingAccurate 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).
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ArticleAn assessment of the Atlantic and Arctic sea–air CO2 fluxes, 1990–2009(Copernicus Publications on behalf of the European Geosciences Union, 2013-01-29) Schuster, Ute ; McKinley, Galen A. ; Bates, Nicholas R. ; Chevallier, Frédéric ; Doney, Scott C. ; Fay, A. R. ; Gonzalez-Davila, M. ; Gruber, Nicolas ; Jones, S. ; Krijnen, J. ; Landschutzer, Peter ; Lefevre, N. ; Manizza, Manfredi ; Mathis, Jeremy T. ; Metzl, Nicolas ; Olsen, Are ; Rios, Aida F. ; Rodenbeck, C. ; Santana-Casiano, J. M. ; Takahashi, Taro ; Wanninkhof, Rik ; Watson, Andrew J.The Atlantic and Arctic Oceans are critical components of the global carbon cycle. Here we quantify the net sea–air CO2 flux, for the first time, across different methodologies for consistent time and space scales for the Atlantic and Arctic basins. We present the long-term mean, seasonal cycle, interannual variability and trends in sea–air CO2 flux for the period 1990 to 2009, and assign an uncertainty to each. We use regional cuts from global observations and modeling products, specifically a pCO2-based CO2 flux climatology, flux estimates from the inversion of oceanic and atmospheric data, and results from six ocean biogeochemical models. Additionally, we use basin-wide flux estimates from surface ocean pCO2 observations based on two distinct methodologies. Our estimate of the contemporary sea–air flux of CO2 (sum of anthropogenic and natural components) by the Atlantic between 40° S and 79° N is −0.49 ± 0.05 Pg C yr−1, and by the Arctic it is −0.12 ± 0.06 Pg C yr−1, leading to a combined sea–air flux of −0.61 ± 0.06 Pg C yr−1 for the two decades (negative reflects ocean uptake). We do find broad agreement amongst methodologies with respect to the seasonal cycle in the subtropics of both hemispheres, but not elsewhere. Agreement with respect to detailed signals of interannual variability is poor, and correlations to the North Atlantic Oscillation are weaker in the North Atlantic and Arctic than in the equatorial region and southern subtropics. Linear trends for 1995 to 2009 indicate increased uptake and generally correspond between methodologies in the North Atlantic, but there is disagreement amongst methodologies in the equatorial region and southern subtropics.
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ArticleGlobal carbon budget 2014(Copernicus Publications, 2015-05-08) Le Quere, Corinne ; Moriarty, Roisin ; Andrew, Robbie M. ; Peters, Glen P. ; Ciais, Philippe ; Friedlingstein, Pierre ; Jones, S. D. ; Sitch, Stephen ; Tans, Pieter P. ; Arneth, Almut ; Boden, Thomas A. ; Bopp, Laurent ; Bozec, Yann ; Canadell, Josep G. ; Chini, Louise Parsons ; Chevallier, Frédéric ; Cosca, Catherine E. ; Harris, Ian ; Hoppema, Mario ; Houghton, Richard A. ; House, Jo I. ; Jain, Atul K. ; Johannessen, T. ; Kato, Etsushi ; Keeling, Ralph F. ; Kitidis, Vassilis ; Klein Goldewijk, Kees ; Koven, Charles ; Landa, C. S. ; Landschutzer, Peter ; Lenton, Andrew ; Lima, Ivan D. ; Marland, G. ; Mathis, Jeremy T. ; Metzl, Nicolas ; Nojiri, Yukihiro ; Olsen, Are ; Ono, Tsuneo ; Peng, S. ; Peters, W. ; Pfeil, Benjamin ; Poulter, Benjamin ; Raupach, Michael R. ; Regnier, P. ; Rodenbeck, C. ; Saito, Shu ; Salisbury, Joseph E. ; Schuster, Ute ; Schwinger, Jorg ; Seferian, Roland ; Segschneider, J. ; Steinhoff, Tobias ; Stocker, Benjamin D. ; Sutton, Adrienne J. ; Takahashi, Taro ; Tilbrook, Bronte ; van der Werf, Guido R. ; Viovy, Nicolas ; Wang, Y.-P. ; Wanninkhof, Rik ; Wiltshire, Andrew J. ; Zeng, NingAccurate 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, consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuel combustion and cement production (EFF) are based on energy statistics and cement production data, respectively, 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 (2004–2013), EFF was 8.9 ± 0.4 GtC yr−1, ELUC 0.9 ± 0.5 GtC yr−1, GATM 4.3 ± 0.1 GtC yr−1, SOCEAN 2.6 ± 0.5 GtC yr−1, and SLAND 2.9 ± 0.8 GtC yr−1. For year 2013 alone, EFF grew to 9.9 ± 0.5 GtC yr−1, 2.3% above 2012, continuing the growth trend in these emissions, ELUC was 0.9 ± 0.5 GtC yr−1, GATM was 5.4 ± 0.2 GtC yr−1, SOCEAN was 2.9 ± 0.5 GtC yr−1, and SLAND was 2.5 ± 0.9 GtC yr−1. GATM was high in 2013, reflecting a steady increase in EFF and smaller and opposite changes between SOCEAN and SLAND compared to the past decade (2004–2013). The global atmospheric CO2 concentration reached 395.31 ± 0.10 ppm averaged over 2013. We estimate that EFF will increase by 2.5% (1.3–3.5%) to 10.1 ± 0.6 GtC in 2014 (37.0 ± 2.2 GtCO2 yr−1), 65% above emissions in 1990, based on projections of world gross domestic product and recent changes in the carbon intensity of the global economy. From this projection of EFF and assumed constant ELUC for 2014, cumulative emissions of CO2 will reach about 545 ± 55 GtC (2000 ± 200 GtCO2) for 1870–2014, about 75% from EFF and 25% from ELUC. This paper documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this living data set (Le Quéré et al., 2013, 2014). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP_2014).