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PreprintSkill metrics for confronting global upper ocean ecosystem-biogeochemistry models against field and remote sensing data( 2008-03-04) Doney, Scott C. ; Lima, Ivan D. ; Moore, J. Keith ; Lindsay, Keith ; Behrenfeld, Michael J. ; Westberry, Toby K. ; Mahowald, Natalie M. ; Glover, David M. ; Takahashi, TaroWe present a generalized framework for assessing the skill of global upper ocean ecosystem-biogeochemical models against in-situ field data and satellite observations. We illustrate the approach utilizing a multi-decade (1979-2004) hindcast experiment conducted with the Community Climate System Model (CCSM-3) ocean carbon model. The CCSM-3 ocean carbon model incorporates a multi-nutrient, multi-phytoplankton functional group ecosystem module coupled with a carbon, oxygen, nitrogen, phosphorus, silicon, and iron biogeochemistry module embedded in a global, threedimensional ocean general circulation model. The model is forced with physical climate forcing from atmospheric reanalysis and satellite data products and time-varying atmospheric dust deposition. Data-based skill metrics are used to evaluate the simulated time-mean spatial patterns, seasonal cycle amplitude and phase, and subannual to interannual variability. Evaluation data include: sea surface temperature and mixed layer depth; satellite derived surface ocean chlorophyll, primary productivity, phytoplankton growth rate and carbon biomass; large-scale climatologies of surface nutrients, pCO2, and air-sea CO2 and O2 flux; and time-series data from the Joint Global Ocean Flux Study (JGOFS). Where the data is sufficient, we construct quantitative skill metrics using: model-data residuals, time-space correlation, root mean square error, and Taylor diagrams.
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ArticleNorth Pacific carbon cycle response to climate variability on seasonal to decadal timescales(American Geophysical Union, 2006-07-04) McKinley, Galen A. ; Takahashi, Taro ; Buitenhuis, Erik T. ; Chai, Fei ; Christian, James R. ; Doney, Scott C. ; Jiang, Mingshun ; Lindsay, Keith ; Moore, J. Keith ; Le Quere, Corinne ; Lima, Ivan D. ; Murtugudde, Raghu ; Shi, L. ; Wetzel, PatrickClimate variability drives significant changes in the physical state of the North Pacific, and thus there may be important impacts of climate variability on the upper ocean carbon balance across the basin. We address this issue by considering the response of seven biogeochemical ocean models to climate variability in the North Pacific. The models’ upper ocean pCO2 and air-sea CO2 flux respond similarly to climate variability on seasonal to decadal timescales. Modeled seasonal cycles of pCO2 and its temperature and non-temperature driven components at three contrasting oceanographic sites capture the basic features found in observations [Takahashi et al., 2002, 2006; Keeling et al., 2004; Brix et al., 2004]. However, particularly in the Western Subarctic Gyre, the models have difficulty representing the temporal structure of the total pCO2 cycle because it results from the difference of these two large and opposing components. In all but one model, the airsea CO2 flux interannual variability (1σ) in the North Pacific is smaller (ranges across models from 0.03 to 0.11 PgC/yr) than in the Tropical Pacific (ranges across models from 0.08 to 0.19 PgC/yr), and the timeseries of the first or second EOF of the air-sea CO2 flux has a significant correlation with the Pacific Decadal Oscillation (PDO). Though air-sea CO2 flux anomalies are correlated with the PDO, their magnitudes are small (up to ±0.025 PgC/yr (1σ)). Flux anomalies are damped because anomalies in the key drivers of pCO2 (temperature, dissolved inorganic carbon (DIC) and alkalinity) are all of similar magnitude and have strongly opposing effects that damp total pCO2 anomalies.
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ArticleGlobal ocean carbon uptake : magnitude, variability and trends(Copernicus Publications on behalf of the European Geosciences Union, 2013-03-22) Wanninkhof, Rik ; Park, Geun-Ha ; Takahashi, Taro ; Sweeney, Colm ; Feely, Richard A. ; Nojiri, Yukihiro ; Gruber, Nicolas ; Doney, Scott C. ; McKinley, Galen A. ; Lenton, Andrew ; Le Quere, Corinne ; Heinze, Christoph ; Schwinger, Jorg ; Graven, Heather ; Khatiwala, SamarThe globally integrated sea–air anthropogenic carbon dioxide (CO2) flux from 1990 to 2009 is determined from models and data-based approaches as part of the Regional Carbon Cycle Assessment and Processes (RECCAP) project. Numerical methods include ocean inverse models, atmospheric inverse models, and ocean general circulation models with parameterized biogeochemistry (OBGCMs). The median value of different approaches shows good agreement in average uptake. The best estimate of anthropogenic CO2 uptake for the time period based on a compilation of approaches is −2.0 Pg C yr−1. The interannual variability in the sea–air flux is largely driven by large-scale climate re-organizations and is estimated at 0.2 Pg C yr−1 for the two decades with some systematic differences between approaches. The largest differences between approaches are seen in the decadal trends. The trends range from −0.13 (Pg C yr−1) decade−1 to −0.50 (Pg C yr−1) decade−1 for the two decades under investigation. The OBGCMs and the data-based sea–air CO2 flux estimates show appreciably smaller decadal trends than estimates based on changes in carbon inventory suggesting that methods capable of resolving shorter timescales are showing a slowing of the rate of ocean CO2 uptake. RECCAP model outputs for five decades show similar differences in trends between approaches.
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ArticleOceanic sources, sinks, and transport of atmospheric CO2(American Geophysical Union, 2009-02-18) Gruber, Nicolas ; Gloor, Emanuel ; Mikaloff Fletcher, Sara E. ; Doney, Scott C. ; Dutkiewicz, Stephanie ; Follows, Michael J. ; Gerber, Markus ; Jacobson, Andrew R. ; Joos, Fortunat ; Lindsay, Keith ; Menemenlis, Dimitris ; Mouchet, Anne ; Muller, Simon A. ; Sarmiento, Jorge L. ; Takahashi, TaroWe synthesize estimates of the contemporary net air-sea CO2 flux on the basis of an inversion of interior ocean carbon observations using a suite of 10 ocean general circulation models (Mikaloff Fletcher et al., 2006, 2007) and compare them to estimates based on a new climatology of the air-sea difference of the partial pressure of CO2 (pCO2) (Takahashi et al., 2008). These two independent flux estimates reveal a consistent description of the regional distribution of annual mean sources and sinks of atmospheric CO2 for the decade of the 1990s and the early 2000s with differences at the regional level of generally less than 0.1 Pg C a−1. This distribution is characterized by outgassing in the tropics, uptake in midlatitudes, and comparatively small fluxes in thehigh latitudes. Both estimates point toward a small (∼ −0.3 Pg C a−1) contemporary CO2 sink in the Southern Ocean (south of 44°S), a result of the near cancellation between a substantial outgassing of natural CO2 and a strong uptake of anthropogenic CO2. A notable exception in the generally good agreement between the two estimates exists within the Southern Ocean: the ocean inversion suggests a relatively uniform uptake, while the pCO2-based estimate suggests strong uptake in the region between 58°S and 44°S, and a source in the region south of 58°S. Globally and for a nominal period between 1995 and 2000, the contemporary net air-sea flux of CO2 is estimated to be −1.7 ± 0.4 Pg C a−1 (inversion) and −1.4 ± 0.7 Pg C a−1 (pCO2-climatology), respectively, consisting of an outgassing flux of river-derived carbon of ∼+0.5 Pg C a−1, and an uptake flux of anthropogenic carbon of −2.2 ± 0.3 Pg C a−1 (inversion) and −1.9 ± 0.7 Pg C a−1 (pCO2-climatology). The two flux estimates also imply a consistent description of the contemporary meridional transport of carbon with southward ocean transport throughout most of the Atlantic basin, and strong equatorward convergence in the Indo-Pacific basins. Both transport estimates suggest a small hemispheric asymmetry with a southward transport of between −0.2 and −0.3 Pg C a−1 across the equator. While the convergence of these two independent estimates is encouraging and suggests that it is now possible to provide relatively tight constraints for the net air-sea CO2 fluxes at the regional basis, both studies are limited by their lack of consideration of long-term changes in the ocean carbon cycle, such as the recent possible stalling in the expected growth of the Southern Ocean carbon sink.
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ArticleAir-sea CO2 flux in the Pacific Ocean for the period 1990–2009(Copernicus Publications on behalf of the European Geosciences Union, 2014-02-06) Ishii, Masao ; Feely, Richard A. ; Rodgers, Keith B. ; Park, Geun-Ha ; Wanninkhof, Rik ; Sasano, D. ; Sugimoto, H. ; Cosca, Catherine E. ; Nakaoka, Shin-ichiro ; Telszewski, Maciej ; Nojiri, Yukihiro ; Mikaloff Fletcher, Sara E. ; Niwa, Y. ; Patra, Prabir K. ; Valsala, V. ; Nakano, Hideyuki ; Lima, Ivan D. ; Doney, Scott C. ; Buitenhuis, Erik T. ; Aumont, Olivier ; Dunne, John P. ; Lenton, Andrew ; Takahashi, TaroAir–sea CO2 fluxes over the Pacific Ocean are known to be characterized by coherent large-scale structures that reflect not only ocean subduction and upwelling patterns, but also the combined effects of wind-driven gas exchange and biology. On the largest scales, a large net CO2 influx into the extratropics is associated with a robust seasonal cycle, and a large net CO2 efflux from the tropics is associated with substantial interannual variability. In this work, we have synthesized estimates of the net air–sea CO2 flux from a variety of products, drawing upon a variety of approaches in three sub-basins of the Pacific Ocean, i.e., the North Pacific extratropics (18–66° N), the tropical Pacific (18° S–18° N), and the South Pacific extratropics (44.5–18° S). These approaches include those based on the measurements of CO2 partial pressure in surface seawater (pCO2sw), inversions of ocean-interior CO2 data, forward ocean biogeochemistry models embedded in the ocean general circulation models (OBGCMs), a model with assimilation of pCO2sw data, and inversions of atmospheric CO2 measurements. Long-term means, interannual variations and mean seasonal variations of the regionally integrated fluxes were compared in each of the sub-basins over the last two decades, spanning the period from 1990 through 2009. A simple average of the long-term mean fluxes obtained with surface water pCO2 diagnostics and those obtained with ocean-interior CO2 inversions are −0.47 ± 0.13 Pg C yr−1 in the North Pacific extratropics, +0.44 ± 0.14 Pg C yr−1 in the tropical Pacific, and −0.37 ± 0.08 Pg C yr−1 in the South Pacific extratropics, where positive fluxes are into the atmosphere. This suggests that approximately half of the CO2 taken up over the North and South Pacific extratropics is released back to the atmosphere from the tropical Pacific. These estimates of the regional fluxes are also supported by the estimates from OBGCMs after adding the riverine CO2 flux, i.e., −0.49 ± 0.02 Pg C yr−1 in the North Pacific extratropics, +0.41 ± 0.05 Pg C yr−1 in the tropical Pacific, and −0.39 ± 0.11 Pg C yr−1 in the South Pacific extratropics. The estimates from the atmospheric CO2 inversions show large variations amongst different inversion systems, but their median fluxes are consistent with the estimates from climatological pCO2sw data and pCO2sw diagnostics. In the South Pacific extratropics, where CO2 variations in the surface and ocean interior are severely undersampled, the difference in the air–sea CO2 flux estimates between the diagnostic models and ocean-interior CO2 inversions is larger (0.18 Pg C yr−1). The range of estimates from forward OBGCMs is also large (−0.19 to −0.72 Pg C yr−1). Regarding interannual variability of air–sea CO2 fluxes, positive and negative anomalies are evident in the tropical Pacific during the cold and warm events of the El Niño–Southern Oscillation in the estimates from pCO2sw diagnostic models and from OBGCMs. They are consistent in phase with the Southern Oscillation Index, but the peak-to-peak amplitudes tend to be higher in OBGCMs (0.40 ± 0.09 Pg C yr−1) than in the diagnostic models (0.27 ± 0.07 Pg C yr−1).
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ArticleSignificant biologically mediated CO2 uptake in the pacific arctic during the late open water season.(American Geophysical Union, 2019-01-10) Juranek, Laurie W. ; Takahashi, Taro ; Mathis, Jeremy T. ; Pickart, Robert S.Shifting baselines in the Arctic atmosphere‐sea ice‐ocean system have significant potential to alter biogeochemical cycling and ecosystem dynamics. In particular, the impact of increased open water duration on lower trophic level productivity and biological CO2 sequestration is poorly understood. Using high‐resolution observations of surface seawater dissolved O2/Ar and pCO2 collected in the Pacific Arctic in October 2011 and 2012, we evaluate spatial variability in biological metabolic status (autotrophy vs heterotrophy) as constrained by O2/Ar saturation (∆O2/Ar) as well as the relationship between net biological production and the sea‐air gradient of pCO2 (∆pCO2). We find a robust relationship between ∆pCO2 and ∆O2/Ar (correlation coefficient of −0.74 and −0.61 for 2011 and 2012, respectively), which suggests that biological production in the late open water season is an important determinant of the air‐sea CO2 gradient at a timeframe of maximal ocean uptake for CO2 in this region. Patchiness in biological production as indicated by ∆O2/Ar suggests spatially variable nutrient supply mechanisms supporting late season growth amidst a generally strongly stratified and nutrient‐limited condition.
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ArticleChanges in deep-water CO2 concentrations over the last several decades determined from discrete pCO2 measurements(Elsevier Ltd, 2013-02-09) Wanninkhof, Rik ; Park, Geun-Ha ; Takahashi, Taro ; Feely, Richard A. ; Bullister, John L. ; Doney, Scott C.Detection and attribution of hydrographic and biogeochemical changes in the deep ocean are challenging due to the small magnitude of their signals and to limitations in the accuracy of available data. However, there are indications that anthropogenic and climate change signals are starting to manifest at depth. The deep ocean below 2000 m comprises about 50% of the total ocean volume, and changes in the deep ocean should be followed over time to accurately assess the partitioning of anthropogenic carbon dioxide (CO2) between the ocean, terrestrial biosphere, and atmosphere. Here we determine the changes in the interior deep-water inorganic carbon content by a novel means that uses the partial pressure of CO2 measured at 20 °C, pCO2(20), along three meridional transects in the Atlantic and Pacific oceans. These changes are measured on decadal time scales using observations from the World Ocean Circulation Experiment (WOCE)/World Hydrographic Program (WHP) of the 1980s and 1990s and the CLIVAR/CO2 Repeat Hydrography Program of the past decade. The pCO2(20) values show a consistent increase in deep water over the time period. Changes in total dissolved inorganic carbon (DIC) content in the deep interior are not significant or consistent, as most of the signal is below the level of analytical uncertainty. Using an approximate relationship between pCO2(20) and DIC change, we infer DIC changes that are at the margin of detectability. However, when integrated on the basin scale, the increases range from 8–40% of the total specific water column changes over the past several decades. Patterns in chlorofluorocarbons (CFCs), along with output from an ocean model, suggest that the changes in pCO2(20) and DIC are of anthropogenic origin.
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ArticleTwo decades of inorganic carbon dynamics along the West Antarctic Peninsula(Copernicus Publications on behalf of the European Geosciences Union, 2015-11-26) Hauri, Claudine ; Doney, Scott C. ; Takahashi, Taro ; Erickson, Matthew ; Jiang, G. ; Ducklow, Hugh W.We present 20 years of seawater inorganic carbon measurements collected along the western shelf and slope of the Antarctic Peninsula. Water column observations from summertime cruises and seasonal surface underway pCO2 measurements provide unique insights into the spatial, seasonal, and interannual variability in this dynamic system. Discrete measurements from depths > 2000 m align well with World Ocean Circulation Experiment observations across the time series and underline the consistency of the data set. Surface total alkalinity and dissolved inorganic carbon data showed large spatial gradients, with a concomitant wide range of Ωarag (< 1 up to 3.9). This spatial variability was mainly driven by increasing influence of biological productivity towards the southern end of the sampling grid and meltwater input along the coast towards the northern end. Large inorganic carbon drawdown through biological production in summer caused high near-shore Ωarag despite glacial and sea-ice meltwater input. In support of previous studies, we observed Redfield behavior of regional C / N nutrient utilization, while the C / P (80.5 ± 2.5) and N / P (11.7 ± 0.3) molar ratios were significantly lower than the Redfield elemental stoichiometric values. Seasonal salinity-based predictions of Ωarag suggest that surface waters remained mostly supersaturated with regard to aragonite throughout the study. However, more than 20 % of the predictions for winters and springs between 1999 and 2013 resulted in Ωarag < 1.2. Such low levels of Ωarag may have implications for important organisms such as pteropods. Even though we did not detect any statistically significant long-term trends, the combination of on\-going ocean acidification and freshwater input may soon induce more unfavorable conditions than the ecosystem experiences today.
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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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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).
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ArticleGlobal carbon budget 2013(Copernicus Publications., 2014-06-17) Le Quere, Corinne ; Peters, Glen P. ; Andres, Robert J. ; Andrew, Robbie M. ; Boden, Thomas A. ; Ciais, Philippe ; Friedlingstein, Pierre ; Houghton, Richard A. ; Marland, G. ; Moriarty, Roisin ; Sitch, Stephen ; Tans, Pieter P. ; Arneth, Almut ; Arvanitis, A. ; Bakker, Dorothee C. E. ; Bopp, Laurent ; Canadell, Josep G. ; Chini, Louise Parsons ; Doney, Scott C. ; Harper, Anna B. ; Harris, Ian ; House, Jo I. ; Jain, Atul K. ; Jones, S. D. ; Kato, Etsushi ; Keeling, Ralph F. ; Klein Goldewijk, Kees ; Kortzinger, A. ; Koven, Charles ; Lefevre, N. ; Maignan, F. ; Omar, A. ; Ono, Tsuneo ; Park, Geun-Ha ; Pfeil, Benjamin ; Poulter, Benjamin ; Raupach, Michael R. ; Regnier, P. ; Rodenbeck, C. ; Saito, Shu ; Schwinger, Jorg ; Segschneider, J. ; Stocker, Benjamin D. ; Takahashi, Taro ; Tilbrook, Bronte ; van Heuven, Steven ; Viovy, Nicolas ; Wanninkhof, Rik ; Wiltshire, Andrew J. ; Zaehle, SonkeAccurate 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, 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 for the first time in this budget 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). 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 (2003–2012), EFF was 8.6 ± 0.4 GtC yr−1, ELUC 0.9 ± 0.5 GtC yr−1, GATM 4.3 ± 0.1 GtC yr−1, SOCEAN 2.5 ± 0.5 GtC yr−1, and SLAND 2.8 ± 0.8 GtC yr−1. For year 2012 alone, EFF grew to 9.7 ± 0.5 GtC yr−1, 2.2% above 2011, reflecting a continued growing trend in these emissions, GATM was 5.1 ± 0.2 GtC yr−1, SOCEAN was 2.9 ± 0.5 GtC yr−1, and assuming an ELUC of 1.0 ± 0.5 GtC yr−1 (based on the 2001–2010 average), SLAND was 2.7 ± 0.9 GtC yr−1. GATM was high in 2012 compared to the 2003–2012 average, almost entirely reflecting the high EFF. The global atmospheric CO2 concentration reached 392.52 ± 0.10 ppm averaged over 2012. We estimate that EFF will increase by 2.1% (1.1–3.1%) to 9.9 ± 0.5 GtC in 2013, 61% above emissions in 1990, based on projections of world gross domestic product and recent changes in the carbon intensity of the economy. With this projection, cumulative emissions of CO2 will reach about 535 ± 55 GtC for 1870–2013, about 70% from EFF (390 ± 20 GtC) and 30% from ELUC (145 ± 50 GtC).