Climate change during Cenozoic inferred from global carbon cycle model including igneous and hydrothermal activities

2003 ◽  
Vol 199 (3-4) ◽  
pp. 167-185 ◽  
Author(s):  
Hirohiko Kashiwagi ◽  
Naotatsu Shikazono
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Global Carbon Cycle ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Hydrothermal Activities ◽  
Global Carbon

scholarly journals Explaining the seasonal cycle of the globally averaged CO<sub>2</sub> with a carbon cycle model

2014 ◽  
Vol 5 (1) ◽  
pp. 63-81 ◽  
Author(s):  
G. A. Alexandrov
Keyword(s):  
Carbon Cycle ◽  
Seasonal Changes ◽  
Seasonal Cycle ◽  
Global Carbon Cycle ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Observation Network ◽  
Model Components ◽  
Atmospheric Concentrations ◽  
Global Carbon

Abstract. The discrepancy between simulated and observed globally averaged monthly atmospheric concentrations of carbon dioxide could be attributed either to deficiencies in the observation network or to inadequacies in the global carbon cycle models. This paper shows that model results could be brought closer to observations by improving model components that describe the seasonal changes in the storage of quickly decaying fractions of litter.

scholarly journals Explaining the seasonal cycle of the globally averaged CO<sub>2</sub> with a carbon-cycle model

2014 ◽  
Vol 5 (2) ◽  
pp. 345-354 ◽  
Author(s):  
G. A. Alexandrov
Keyword(s):  
Carbon Dioxide ◽  
Carbon Cycle ◽  
Seasonal Variations ◽  
Atmospheric Carbon Dioxide ◽  
Global Carbon Cycle ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Carbon Dioxide Concentrations ◽  
Atmospheric Carbon ◽  
Global Carbon

Abstract. The seasonal changes in the globally averaged atmospheric carbon-dioxide concentrations reflect an important aspect of the global carbon cycle: the gas exchange between the atmosphere and terrestrial biosphere. The data on the globally averaged atmospheric carbon-dioxide concentrations, which are reported by Earth System Research Laboratory of the US National Oceanic &amp; Atmospheric Administration (NOAA/ESRL), could be used to demonstrate the adequacy of the global carbon-cycle models. However, it was recently found that the observed amplitude of seasonal variations in the atmospheric carbon-dioxide concentrations is higher than simulated. In this paper, the factors that affect the amplitude of seasonal variations are explored using a carbon-cycle model of reduced complexity. The model runs show that the low amplitude of the simulated seasonal variations may result from underestimated effect of substrate limitation on the seasonal pattern of heterotrophic respiration and from an underestimated magnitude of the annual gross primary production (GPP) in the terrestrial ecosystems located to the north of 25° N.

A simple global carbon-cycle model

Energy ◽  
1994 ◽  
Vol 19 (8) ◽  
pp. 825-829 ◽  
Author(s):  
K. Kamiuto
Keyword(s):  
Carbon Cycle ◽  
Global Carbon Cycle ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
Global Carbon

Time-scale dependence of climate-carbon cycle feedbacks for weak perturbations in CMIP5 models

2021 ◽  
Author(s):  
Guilherme Torres Mendonça ◽  
Julia Pongratz ◽  
Christian Reick
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Time Scales ◽  
Radiative Forcing ◽  
Global Carbon Cycle ◽  
Atmospheric Co2 ◽  
Ice Age ◽  
Cmip5 Models ◽  
Global Carbon ◽  
Different Time Scales

&lt;p&gt;The increase in atmospheric CO2 driven by anthropogenic emissions is the main radiative forcing causing climate change. But this increase is not only a result from emissions, but also from changes in the global carbon cycle. These changes arise from feedbacks between climate and the carbon cycle that drive CO2 into or out of the atmosphere in addition to the emissions, thereby either accelerating or buffering climate change. Therefore, understanding the contribution of these feedbacks to the global response of the carbon cycle is crucial in advancing climate research. Currently, this contribution is quantified by the &amp;#945;-&amp;#946;-&amp;#947; framework (Friedlingstein et al., 2003). But this quantification is only valid for a particular perturbation scenario and time period. In contrast, a recently proposed generalization (Rubino et al., 2016) of this framework for weak perturbations quantifies this contribution for all scenarios and at different time scales.&amp;#160;&lt;/p&gt;&lt;p&gt;Thereby, this generalization provides a systematic framework to investigate the response of the global carbon cycle in terms of the climate-carbon cycle feedbacks. In the present work we employ this framework to study these feedbacks and the airborne fraction in different CMIP5 models. We demonstrate (1) that this generalization of the &amp;#945;-&amp;#946;-&amp;#947; framework consistently describes the linear dynamics of the carbon cycle in the MPI-ESM; and (2) how by this framework the climate-carbon cycle feedbacks and airborne fraction are quantified at different time scales in CMIP5 models. Our analysis shows that, independently of the perturbation scenario, (1) the net climate-carbon cycle feedback is negative at all time scales; (2) the airborne fraction generally decreases for increasing time scales; and (3) the land biogeochemical feedback dominates the model spread in the airborne fraction at all time scales. This last result therefore emphasizes the need to improve our understanding of this particular feedback.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;P. Friedlingstein, J.-L. Dufresne, P. Cox, and P. Rayner. How positive is the feedback between climate change and the carbon cycle? Tellus B, 55(2):692&amp;#8211;700, 2003.&lt;/p&gt;&lt;p&gt;M. Rubino, D. Etheridge, C. Trudinger, C. Allison, P. Rayner, I. Enting, R. Mulvaney, L. Steele, R. Langenfelds, W. Sturges, et al. Low atmospheric CO2 levels during the Little Ice Age due to cooling-induced terrestrial uptake. Nature Geoscience, 9(9):691&amp;#8211;694, 2016.&lt;/p&gt;

scholarly journals Reviews and syntheses: Systematic Earth observations for use in terrestrial carbon cycle data assimilation systems

2017 ◽  
Author(s):  
Marko Scholze ◽  
Michael Buchwitz ◽  
Wouter Dorigo ◽  
Luis Guanter ◽  
Shaun Quegan
Keyword(s):  
Data Assimilation ◽  
Carbon Cycle ◽  
Global Carbon Cycle ◽  
Full Description ◽  
Model Data ◽  
Terrestrial Carbon ◽  
Carbon Cycle Model ◽  
Terrestrial Carbon Cycle ◽  
Uncertainty Estimates ◽  
Global Carbon

Abstract. The global carbon cycle is an important component of the Earth system and it interacts with the hydrological, energy and nutrient cycles as well as ecosystem dynamics. A better understanding of the global carbon cycle is required for improved projections of climate change including corresponding changes in water and food resources and for the verification 5 of measures to reduce anthropogenic greenhouse gas emissions. An improved understanding of the carbon cycle can be achieved by model-data fusion or data assimilation systems, which integrate observations relevant to the carbon cycle into coupled carbon, water, energy and nutrient models. Hence, the ingredients for such systems are a carbon cycle model, an algorithm for the assimilation, and systematic and 10 well error-characterized observations relevant to the carbon cycle. Relevant observations for assimilation include various in-situ measurements in the atmosphere (e.g. concentrations of CO2 and other gases) and on land (e.g. fluxes of carbon water and energy, carbon stocks) as well as remote sensing observations (e.g. atmospheric composition, vegetation and surface properties).We briefly review the different existing data assimilation techniques and contrast them to model 15 benchmarking and evaluation efforts (which also rely on observations). A common requirement for all assimilation techniques is a full description of the observational data properties. Uncertainty estimates of the observations are as important as the observations themselves because they similarly determine the outcome of such assimilation systems. Hence, this article reviews the requirements of data assimilation systems on observations and provides a non-exhaustive overview of current 20 observations and their uncertainties for use in terrestrial carbon cycle data assimilation. We report on progress since the review of model-data synthesis in terrestrial carbon observations by Raupach et al. (2005) emphasising the rapid advance in relevant space-based observations.

scholarly journals Comment on "Carbon farming in hot, dry coastal areas: an option for climate change mitigation" by Becker et al. (2013)

2013 ◽  
Vol 4 (2) ◽  
pp. 869-873
Author(s):  
M. Heimann
Keyword(s):  
Carbon Cycle ◽  
Carbon Sink ◽  
Co2 Concentration ◽  
Global Carbon Cycle ◽  
Atmospheric Co2 ◽  
Reference Scenario ◽  
Carbon Cycle Model ◽  
Terrestrial Carbon Sink ◽  
Carbon Dioxide Co2 ◽  
Global Carbon

Abstract. Becker et al. (2013) argue that an afforestation of 0.73 109 ha with Jatropha curcas plants would generate an additional terrestrial carbon sink of 4.3 PgC yr−1, enough to stabilise the atmospheric mixing ratio of carbon dioxide (CO2) at current levels. However, this is not consistent with the dynamics of the global carbon cycle. Using a well established global carbon cycle model, the effect of adding such a hypothetical sink leads to a reduction of atmospheric CO2 levels in the year 2030 by 25 ppm compared to a reference scenario. However, the stabilisation of the atmospheric CO2 concentration requires a much larger additional sink or corresponding reduction of anthropogenic emissions.

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