Papers on the ocean carbon dioxide sink

This is a list of papers on the measurements of ocean uptake of atmospheric carbon dioxide. The list is not complete, and will most likely be updated in the future in order to make it more thorough and more representative.

The oceanic sink for anthropogenic CO2 from 1994 to 2007 – Gruber et al. (2019). “…we find a global increase in the anthropogenic CO₂ inventory of 34 ± 4 petagrams of carbon (Pg C) between 1994 and 2007. This is equivalent to an average uptake rate of 2.6 ± 0.3 Pg C year⁻¹ and represents 31 ± 4% of the global anthropogenic CO₂ emissions over this period.” [FULL TEXT]

Rapid anthropogenic changes in CO2 and pH in the Atlantic Ocean: 2003–2014 – Woosley et al. (2016). “The results show a significant increase in basin-wide anthropogenic carbon storage in the North Atlantic, which absorbed 4.4 ± 0.9 Pg C decade⁻¹ from 2003 to 2014 compared to 1.9 ± 0.4 Pg C decade⁻¹ for the 1989–2003 period. … The uptake of carbon results in a decrease in pH of ~0.0021 ± 0.0007 year⁻¹ for surface waters during the last 10 years, in line with the atmospheric increase in CO₂.” [FULL TEXT]

The oceanic anthropogenic CO2 sink: Storage, air-sea fluxes, and transports over the industrial era – DeVries (2014). “The OCIM-estimated oceanic C_ant storage is 160–166 PgC in 2012, and the oceanic C_ant uptake rate averaged over the period 2000–2010 is 2.6 PgC yr⁻¹ or about 30% of current anthropogenic CO₂ emissions. This result implies a residual (primarily terrestrial) C_ant sink of about 1.6 PgC yr⁻¹ for the same period.” [FULL TEXT]

Changing controls on oceanic radiocarbon: New insights on shallow-to-deep ocean exchange and anthropogenic CO2 uptake – Graven et al. (2012). “Observed oceanic Δ¹⁴C and its changes between the 1980s–90s and 2000s indicate that shallow-to-deep exchange is too efficient in ECCO and too sluggish in CCSM. These findings suggest that mean global oceanic uptake of anthropogenic CO₂ between 1990 and 2007 is bounded by the ECCO-based estimate of 2.3 Pg C yr⁻¹ and the CCSM-based estimate of 1.7 Pg C yr⁻¹.” [FULL TEXT]

Estimation of Anthropogenic CO2 Inventories in the Ocean – Sabine & Tanhua (2010). “Today, the ocean carbon uptake rate estimates suggest that the ocean is not keeping pace with the CO2 emissions growth rate. Repeat occupations of the WOCE/JGOFS survey lines consistently show increases in carbon inventories over the last decade, but have not yet been synthesized enough to verify a slowdown in the carbon storage rate.” [FULL TEXT]

Climatological mean and decadal change in surface ocean pCO₂, and net sea–air CO₂ flux over the global oceans – Takahashi et al. (2009) “A climatological mean distribution for the surface water pCO₂ over the global oceans in non-El Niño conditions has been constructed with spatial resolution of 4° (latitude) ×5° (longitude) for a reference year 2000 based upon about 3 million measurements of surface water pCO₂ obtained from 1970 to 2007. … The annual mean for the contemporary net CO₂ uptake flux over the global oceans is estimated to be −1.6±0.9 Pg-C y⁻¹, which includes an undersampling correction to the direct estimate of −1.4±0.7 Pg-C y⁻¹. Taking the pre-industrial steady-state ocean source of 0.4±0.2 Pg-C y⁻¹ into account, the total ocean uptake flux including the anthropogenic CO₂ is estimated to be −2.0±1.0 Pg-C y⁻¹ in 2000.”

Tracking the Variable North Atlantic Sink for Atmospheric CO₂ – Watson et al. (2009) “Historically, observations have been too sparse to allow accurate tracking of changes in rates of CO₂ uptake over ocean basins, so little is known about how these vary. Here, we show observations indicating substantial variability in the CO₂ uptake by the North Atlantic on time scales of a few years. Further, we use measurements from a coordinated network of instrumented commercial ships to define the annual flux into the North Atlantic, for the year 2005, to a precision of about 10%.”

Saturation of the Southern Ocean CO₂ Sink Due to Recent Climate Change – Le Quéré et al. (2007) “Based on observed atmospheric carbon dioxide (CO₂) concentration and an inverse method, we estimate that the Southern Ocean sink of CO₂ has weakened between 1981 and 2004 by 0.08 petagrams of carbon per year per decade relative to the trend expected from the large increase in atmospheric CO₂. We attribute this weakening to the observed increase in Southern Ocean winds resulting from human activities, which is projected to continue in the future.” [Full text]

An empirical estimate of the Southern Ocean air-sea CO₂ flux – McNeil et al. (2007) “Here we employ an independent method to estimate the Southern Ocean air-sea flux of CO₂ that exploits all available surface ocean measurements for dissolved inorganic carbon (DIC) and total alkalinity (ALK) beyond 1986. … Including the effects of sea ice, we estimate a Southern Ocean (>50°S) CO₂ sink of 0.4 ± 0.25 Pg C/yr. Our analysis also indicates a substantial CO₂ sink of 1.1 ± 0.6 Pg C/yr within the sub-Antarctic zone (40°S–50°S), associated with strong cooling and high winds. … This paper estimates for the first time basic seasonal carbon cycle parameters within the circumpolar Southern Ocean, which have up to now been extremely difficult to measure and sparse.” [Full text]

Inverse estimates of the oceanic sources and sinks of natural CO₂ and the implied oceanic carbon transport – Mikaloff Fletcher et al. (2007) “We use an inverse method to estimate the global-scale pattern of the air-sea flux of natural CO₂, i.e., the component of the CO₂ flux due to the natural carbon cycle that already existed in preindustrial times, on the basis of ocean interior observations of dissolved inorganic carbon (DIC) and other tracers, from which we estimate ΔC_gasex, i.e., the component of the observed DIC that is due to the gas exchange of natural CO₂. … We find a pattern of air-sea flux of natural CO₂ characterized by outgassing in the Southern Ocean between 44°S and 59°S, vigorous uptake at midlatitudes of both hemispheres, and strong outgassing in the tropics.” [Full text]

Decadal variability of the air-sea CO₂ fluxes in the equatorial Pacific Ocean – Feely et al. (2006) “In order to determine the interannual and decadal changes in the air-sea carbon fluxes of the equatorial Pacific, we developed seasonal and interannual relationships between the fugacity of CO₂ (fCO₂) and sea surface temperature (SST) from shipboard data that were applied to high-resolution temperature fields deduced from satellite data to obtain high-resolution large-scale estimates of the regional fluxes. … On average, the surface water fCO₂ in the equatorial region has been increasing at a rate similar to the atmospheric CO₂ increase. In addition, there appears to be a slight increase (∼27%) in the outgassing flux of CO₂ after the 1997–1998 Pacific Decadal Oscillation (PDO) regime shift.”

The Oceanic Sink for Anthropogenic CO₂ – Sabine et al. (2004) “Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO₂) sink for the period from 1800 to 1994 of 118 ± 19 petagrams of carbon. The oceanic sink accounts for 48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO₂ to the atmosphere of about 39 ± 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO₂ emissions stored in the ocean appears to be about one-third of the long-term potential.” [Full text]

Global sea–air CO₂ flux based on climatological surface ocean pCO₂, and seasonal biological and temperature effects – Takahashi et al. (2002) “Based on about 940,000 measurements of surface-water pCO₂ obtained since the International Geophysical Year of 1956–59, the climatological, monthly distribution of pCO₂ in the global surface waters representing mean non-El Niño conditions has been obtained with a spatial resolution of 4°×5° for a reference year 1995. The monthly and annual net sea–air CO₂ flux has been computed using the NCEP/NCAR 41-year mean monthly wind speeds. An annual net uptake flux of CO₂ by the global oceans has been estimated to be 2.2 (+22% or −19%) Pg C yr−1 using the (wind speed)2 dependence of the CO₂ gas transfer velocity of Wanninkhof (J. Geophys. Res. 97 (1992) 7373).” [Full text]

Interannual Variability in the North Atlantic Ocean Carbon Sink – Gruber et al. (2002) “We report an 18-year time series of upper-ocean inorganic carbon observations from the northwestern subtropical North Atlantic near Bermuda that indicates substantial variability in this sink. We deduce that the carbon variability at this site is largely driven by variations in winter mixed-layer depths and by sea surface temperature anomalies.” [Full text]

Uptake and Storage of Carbon Dioxide in the Ocean: The Global CO₂ Survey – Feely et al. (2001) “In this paper, we summarize our present understanding of the exchange of CO₂ across the air-sea interface and the storage of natural and anthropogenic CO₂ in the ocean’s interior.” [Full text]

Anthropogenic CO₂ in the Atlantic Ocean – Gruber (1998). “…In the North Atlantic, anthropogenic CO₂ has already invaded deeply into the interior; north of 50°N it has even reached the bottom. … An anthropogenic CO₂ inventory of about 22 ± 5 Gt C is estimated for the Atlantic north of the equator for 1982, and 18 ± 4 Gt C is estimated for the Atlantic south of the equator for 1989. The Princeton ocean biogeochemistry model predicts anthropogenic CO₂ inventories of 20.0 Gt C (North Atlantic, 1982) and 17.7 Gt C (South Atlantic, 1989) for the same regions in good agreement with the observed inventories.” [FULL TEXT]

Low interannual variability in recent oceanic uptake of atmospheric carbon dioxide – Lee et al. (1998) “Here we estimate the interannual variability in global net air–sea CO₂ flux using changes in the observed wind speeds and the partial pressure of CO₂ (p CO₂) in surface sea water and the overlying air. … The calculated interannual variability in oceanic CO₂ uptake of 0.4 Gt C yr^-1 (2σ) is much less than that inferred from the analysis of atmospheric measurements.”

Quantification of decadal anthropogenic CO₂ uptake in the ocean based on dissolved inorganic carbon measurements – Peng et al. (1998) “Accurate estimates of CO₂ uptake have been difficult to obtain, however, as the annual increase of dissolved inorganic carbon (DIC) concentration in surface water due to anthropogenic input is 0.05% of the total DIC, an order of magnitude lower than past measurement precision. … Here we use recent improvements in DIC measurement techniques to determine changes in DIC concentrations between 1978 and 1995 in the Indian Ocean.”

Global air-sea flux of CO₂: An estimate based on measurements of sea–air pCO₂ difference – Takahashi et al. (1997) “Approximately 250,000 measurements made for the pCO₂ difference between surface water and the marine atmosphere, ΔpCO₂, have been assembled for the global oceans. … The annual net uptake flux of CO₂ by the global oceans thus estimated ranges from 0.60 to 1.34 Gt-C yr⁻¹ depending on different formulations used for wind speed dependence on the gas transfer coefficient. … Temperate and polar oceans of the both hemispheres are the major sinks for atmospheric CO₂, whereas the equatorial oceans are the major sources for CO₂. The Atlantic Ocean is the most important CO₂ sink, providing about 60% of the global ocean uptake, while the Pacific Ocean is neutral because of its equatorial source flux being balanced by the sink flux of the temperate oceans. The Indian and Southern Oceans take up about 20% each.” [Full text]

Atmospheric carbon dioxide and the ocean – Siegenthaler & Sarmiento (1993) “The ocean is a significant sink for anthropogenic carbon dioxide, taking up about a third of the emissions arising from fossil-fuel use and tropical deforestation. Increases in the atmospheric carbon dioxide concentration account for most of the remaining emissions, but there still appears to be a ‘missing sink’ which may be located in the terrestrial biosphere.” [Full text]

Advertisement