Studies on Global Photosynthesis and Its Regulatory Role in Natural Carbon Cycle

2021 ◽  
pp. 1-11
Author(s):  
A. A. Ivlev
Keyword(s):  
Carbon Cycle ◽  
Regulatory Role ◽  
Natural Carbon

scholarly journals Recent changes in the global and regional carbon cycle: analysis of first-order diagnostics

2015 ◽  
Vol 12 (3) ◽  
pp. 835-844 ◽  
Author(s):  
P. J. Rayner ◽  
A. Stavert ◽  
M. Scholze ◽  
A. Ahlström ◽  
C. E. Allison ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Linear Response ◽  
Anthropogenic Emissions ◽  
Seasonal Patterns ◽  
Atmospheric Concentration ◽  
First Order ◽  
Northern Summer ◽  
Data Points ◽  
Natural Carbon ◽  
The Tropics

Abstract. We analyse global and regional changes in CO2 fluxes using two simple models, an airborne fraction of anthropogenic emissions and a linear relationship with CO2 concentrations. We show that both models are able to fit the non-anthropogenic (hereafter natural) flux over the length of the atmospheric concentration record. Analysis of the linear model (including its uncertainties) suggests no significant decrease in the response of the natural carbon cycle. Recent data points rather to an increase. We apply the same linear diagnostic to fluxes from atmospheric inversions. Flux responses show clear regional and seasonal patterns driven by terrestrial uptake in the northern summer. Ocean fluxes show little or no linear response. Terrestrial models show clear responses, agreeing globally with the inversion responses, however the spatial structure is quite different, with dominant responses in the tropics rather than the northern extratropics.

scholarly journals Response of the Ocean Natural Carbon Storage to Projected Twenty-First-Century Climate Change

2014 ◽  
Vol 27 (5) ◽  
pp. 2033-2053 ◽  
Author(s):  
Raffaele Bernardello ◽  
Irina Marinov ◽  
Jaime B. Palter ◽  
Jorge L. Sarmiento ◽  
Eric D. Galbraith ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Carbon Storage ◽  
Wind Stress ◽  
First Century ◽  
High Latitudes ◽  
Co2 Solubility ◽  
Natural Carbon ◽  
Twenty First Century ◽  
Ocean Carbon

Abstract The separate impacts of wind stress, buoyancy fluxes, and CO2 solubility on the oceanic storage of natural carbon are assessed in an ensemble of twentieth- to twenty-first-century simulations, using a coupled atmosphere–ocean–carbon cycle model. Time-varying perturbations for surface wind stress, temperature, and salinity are calculated from the difference between climate change and preindustrial control simulations, and are imposed on the ocean in separate simulations. The response of the natural carbon storage to each perturbation is assessed with novel prognostic biogeochemical tracers, which can explicitly decompose dissolved inorganic carbon into biological, preformed, equilibrium, and disequilibrium components. Strong responses of these components to changes in buoyancy and winds are seen at high latitudes, reflecting the critical role of intermediate and deep waters. Overall, circulation-driven changes in carbon storage are mainly due to changes in buoyancy fluxes, with wind-driven changes playing an opposite but smaller role. Results suggest that climate-driven perturbations to the ocean natural carbon cycle will contribute 20 Pg C to the reduction of the ocean accumulated total carbon uptake over the period 1860–2100. This reflects a strong compensation between a buildup of remineralized organic matter associated with reduced deep-water formation (+96 Pg C) and a decrease of preformed carbon (−116 Pg C). The latter is due to a warming-induced decrease in CO2 solubility (−52 Pg C) and a circulation-induced decrease in disequilibrium carbon storage (−64 Pg C). Climate change gives rise to a large spatial redistribution of ocean carbon, with increasing concentrations at high latitudes and stronger vertical gradients at low latitudes.

scholarly journals Compiled records of carbon isotopes in atmospheric CO<sub>2</sub> for historical simulations in CMIP6

2017 ◽  
Author(s):  
Heather Graven ◽  
Colin E. Allison ◽  
David M. Etheridge ◽  
Samuel Hammer ◽  
Ralph F. Keeling ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Carbon Isotopes ◽  
Coupled Model ◽  
Atmospheric Co2 ◽  
Historical Period ◽  
Terrestrial Biosphere ◽  
Climate Simulations ◽  
Intercomparison Project ◽  
Natural Carbon ◽  
Carbon Cycle Modelling

Abstract. The isotopic composition of carbon (Δ14C and δ13C) in atmospheric CO2 and in oceanic and terrestrial carbon reservoirs is influenced by anthropogenic emissions and by natural carbon exchanges, which can respond to and drive changes in climate. Simulations of 14C and 13C in the ocean and terrestrial components of Earth System Models (ESMs) present opportunities for model evaluation and for investigation of carbon cycling, including anthropogenic CO2 emissions and uptake. The use of carbon isotopes in novel evaluation of the ESMs' component ocean and terrestrial biosphere models and in new analyses of historical changes may improve predictions of future changes in the carbon cycle and climate system. We compile existing data to produce records of Δ14C and δ13C in atmospheric CO2 for the historical period 1850–2015. The primary motivation for this compilation is to provide the atmospheric boundary condition for historical simulations in the Coupled Model Intercomparison Project 6 (CMIP6) for models simulating carbon isotopes in their ocean or terrestrial biosphere models. The data may also be useful for other carbon cycle modelling activities.

The Carbon Cycle

2019 ◽  
pp. 129-158
Author(s):  
Han Dolman
Keyword(s):  
Carbon Cycle ◽  
Primary Production ◽  
Ocean Circulation ◽  
Net Primary Production ◽  
Gross Primary Production ◽  
Carbon Stocks ◽  
Climate Feedback ◽  
Fossil Fuel Burning ◽  
Thermal Maximum ◽  
Natural Carbon

The chapter first shows carbon dioxide variability over long geological timescales. The current stocks and fluxes of carbon are then given, for the whole planet and for the atmosphere, ocean and land separately. The main flows of carbon in the ocean, through the biological pump (via uptake through photosynthesis) and the physical pump (via involving chemical transformation uptake in water and production of carbonate), and on land, through photosynthesis (Gross Primary Production) and respiration leading to Net Primary Production, Net Ecosystem Production and Net Biome Production and through the storage of carbon in biomass, are described. Next, carbon interactions during the Paleocene–Eocene Thermal Maximum and glacial–interglacial transitions, thought to involve changes in ocean circulation and upwelling, are examined. The key changes from anthropogenic perturbation of the natural carbon cycle are shown to be due to fossil fuel burning and land-use change (deforestation). The effects of the carbon–climate feedback on temperature and carbon stocks are also shown.

scholarly journals Compiled records of carbon isotopes in atmospheric CO<sub>2</sub> for historical simulations in CMIP6

2017 ◽  
Vol 10 (12) ◽  
pp. 4405-4417 ◽  
Author(s):  
Heather Graven ◽  
Colin E. Allison ◽  
David M. Etheridge ◽  
Samuel Hammer ◽  
Ralph F. Keeling ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Carbon Isotopes ◽  
Coupled Model ◽  
Atmospheric Co2 ◽  
Historical Period ◽  
Terrestrial Biosphere ◽  
Climate Simulations ◽  
Intercomparison Project ◽  
Natural Carbon ◽  
Carbon Cycle Modelling

Abstract. The isotopic composition of carbon (Δ14C and δ13C) in atmospheric CO2 and in oceanic and terrestrial carbon reservoirs is influenced by anthropogenic emissions and by natural carbon exchanges, which can respond to and drive changes in climate. Simulations of 14C and 13C in the ocean and terrestrial components of Earth system models (ESMs) present opportunities for model evaluation and for investigation of carbon cycling, including anthropogenic CO2 emissions and uptake. The use of carbon isotopes in novel evaluation of the ESMs' component ocean and terrestrial biosphere models and in new analyses of historical changes may improve predictions of future changes in the carbon cycle and climate system. We compile existing data to produce records of Δ14C and δ13C in atmospheric CO2 for the historical period 1850–2015. The primary motivation for this compilation is to provide the atmospheric boundary condition for historical simulations in the Coupled Model Intercomparison Project 6 (CMIP6) for models simulating carbon isotopes in the ocean or terrestrial biosphere. The data may also be useful for other carbon cycle modelling activities.

scholarly journals Impact of Historical Climate Change on the Southern Ocean Carbon Cycle

2008 ◽  
Vol 21 (22) ◽  
pp. 5820-5834 ◽  
Author(s):  
R. J. Matear ◽  
A. Lenton
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Southern Ocean ◽  
Carbon Uptake ◽  
Saturation State ◽  
Aragonite Saturation ◽  
Freshwater Fluxes ◽  
Anthropogenic Carbon ◽  
Natural Carbon ◽  
Ocean Carbon

Abstract Climate change over the last several decades is suggested to cause a decrease in the magnitude of the uptake of CO2 by the Southern Ocean (Le Quere et al.). In this study, the atmospheric fields from NCEP R1 for the years 1948–2003 are used to drive an ocean biogeochemical model to probe how changes in the heat and freshwater fluxes and in the winds affect the Southern Ocean’s uptake of carbon. Over this period, the model simulations herein show that the increases in heat and freshwater fluxes drive a net increase in Southern Ocean uptake (south of 40°S) while the increases in wind stresses drive a net decrease in uptake. The total Southern Ocean response is nearly identical with the simulation without climate change because the heat and freshwater flux response is approximately both equal and opposite to the wind stress response. It is also shown that any change in the Southern Ocean anthropogenic carbon uptake is always opposed by a much larger change in the natural carbon air–sea exchange. For the 1948–2003 period, the changes in the natural carbon cycle dominate the Southern Ocean carbon uptake response to climate change. However, it is shown with a simple box model that when atmospheric CO2 levels exceed the partial pressure of carbon dioxide (pCO2) of the upwelled Circumpolar Deep Water (≈450 μatm) the Southern Ocean uptake response will be dominated by the changes in anthropogenic carbon uptake. Therefore, the suggestion that the Southern Ocean carbon uptake is a positive feedback to global warming is only a transient response that will change to a negative feedback in the near future if the present climate trend continues. Associated with the increased outgassing of carbon from the natural carbon cycle was a reduction in the aragonite saturation state of the high-latitude Southern Ocean (south of 60°S). In the simulation with just wind stress changes, the reduction in the high-latitude Southern Ocean aragonite saturation state (≈0.2) was comparable to the magnitude of the decline in the aragonite saturation state over the last 4 decades because of rising atmospheric CO2 levels (≈0.2). The simulation showed that climate change could significantly impact aragonite saturation state in the Southern Ocean.

Sign in / Sign up

Export Citation Format

Share Document