doi:10.1007/s00376-015-5090-y

Adams J. M., G. Piovesan, 2005: Long series relationships between global interannual CO₂ increment and climate: Evidence for stability and change in role of the tropical and boreal-temperate zones. Chemosphere, 59, 1595- 1612.10.1016/j.chemosphere.2005.03.064

15878607

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http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM15878607

refpaperuri:(44dfe76764f9fbb782787d78cfd217bb)

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM15878607<h2 class="secHeading" id="section_abstract">Abstract</h2>Interannual variability in global CO2 increment (averaged from the Mauna Loa and South Pole Stations) shows certain strong spatial relationships to both tropical and temperate temperatures. There is a fairly strong positive year-round correlation between tropical mean annual temperatures (leading by 4 months) and annual CO2 throughout the time series since 1960, agreeing with the generally held view that the tropics play a major role in determining inter-annual variability in CO2 increment, with a major CO2 pulse following a warm year in the tropics. This ‘almost no lag’ climatic response is very strong during winter and relatively stable in time. However, the correlation with tropical temperature appears to have weakened in the first years of the 1990s in correspondence of the Pinatubo eruption and the positive phase of the AO/NAO. A secondary concurrent temperature signal is linked to summer variations of north temperate belt. Northern summer temperatures in the region 30–60 °N—and especially in the land area corresponding to the central east USA—have become relatively more closely correlated with CO2 increment. This trend has become increasingly stronger in recent years, suggesting an increasing role for growing season processes in the northern midlatitudes in affecting global CO2 increment. Once non-lagged annual tropical temperature variations are accounted for, terrestrial ecosystems, especially the temperate-boreal biomes, also show a coherent large scale lagged response. This involves an inverse response to annual temperature of preceding years centered at around 2 years before. This lagged response is most likely linked to internal biogeochemical cycles, in particular N cycling. During the study period north boreal ecosystems show a strengthening of the lagged correlation with temperature in recent years, while the lagged correlation with areas of tropical ecosystems has weakened. Residuals from a multiple correlations based on these climatic signals are directly correlated with SO, confirming an additional important role of upwelling in interannual variability of CO2 increment. Cooler summers following the Pinatubo eruption and the possible influence of the North Atlantic Oscillation (NAO/AO) are discussed as factors responsible for the shift in the relative importance of different regions over time during the series of data.

Archer D., Coauthors, 2009: Atmospheric lifetime of fossil fuel carbon dioxide. Annual Review of Earth and Planetary Sciences, 37, 117- 134.10.1146/annurev.earth.031208.100206

6b9a0903640d97aaa41498a2e8c514d5

http%3A%2F%2Fwww.annualreviews.org%2Fdoi%2Fabs%2F10.1146%2Fannurev.earth.031208.100206

http://www.annualreviews.org/doi/abs/10.1146/annurev.earth.031208.100206CO2 released from combustion of fossil fuels equilibrates among the various carbon reservoirs of the atmosphere, the ocean, and the terrestrial biosphere on timescales of a few centuries. However, a sizeable fraction of the CO2 remains in the atmosphere, awaiting a return to the solid earth by much slower weathering processes and deposition of CaCO3. Common measures of the atmospheric lifetime of CO2, including the e-folding time scale, disregard the long tail. Its neglect in the calculation of global warming potentials leads many to underestimate the longevity of anthropogenic global warming. Here, we review the past literature on the atmospheric lifetime of fossil fuel CO2 and its impact on climate, and we present initial results from a model intercomparison project on this topic. The models agree that 20-35% of the CO2 remains in the atmosphere after equilibration with the ocean (2-20 centuries). Neutralization by CaCO3 draws the airborne fraction down further on timescales of 3 to 7 kyr.

Arora V.K., Coauthors, 2013: Carbon-concentration and carbon-climate feedbacks in CMIP5 Earth system models. J.Climate, 26, 5289- 5314.10.1175/JCLI-D-12-00494.1

0b0c82446e343bba861f35bc8c9b054f

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F258568304_Carbon-concentration_and_carbon-climate_feedbacks_in_CMIP5_Earth_system_models

http://www.researchgate.net/publication/258568304_Carbon-concentration_and_carbon-climate_feedbacks_in_CMIP5_Earth_system_modelsAbstract The magnitude and evolution of parameters that characterize feedbacks in the coupled carbon–climate system are compared across nine Earth system models (ESMs). The analysis is based on results from biogeochemically, radiatively, and fully coupled simulations in which CO 2 increases at a rate of 1% yr 611 . These simulations are part of phase 5 of the Coupled Model Intercomparison Project (CMIP5). The CO 2 fluxes between the atmosphere and underlying land and ocean respond to changes in atmospheric CO 2 concentration and to changes in temperature and other climate variables. The carbon–concentration and carbon–climate feedback parameters characterize the response of the CO 2 flux between the atmosphere and the underlying surface to these changes. Feedback parameters are calculated using two different approaches. The two approaches are equivalent and either may be used to calculate the contribution of the feedback terms to diagnosed cumulative emissions. The contribution of carbon–concentration feedback to diagnosed cumulative emissions that are consistent with the 1% increasing CO 2 concentration scenario is about 4.5 times larger than the carbon–climate feedback. Differences in the modeled responses of the carbon budget to changes in CO 2 and temperature are seen to be 3–4 times larger for the land components compared to the ocean components of participating models. The feedback parameters depend on the state of the system as well the forcing scenario but nevertheless provide insight into the behavior of the coupled carbon–climate system and a useful common framework for comparing models.

Ballantyne A. P., C. B. Alden, J. B. Miller, P. P. Tans, and J. W. C. White, 2012: Increase in observed net carbon dioxide uptake by land and oceans during the past 50 years. Nature, 488, 70- 72.10.1038/nature11299

22859203

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http%3A%2F%2Feuropepmc.org%2Fabstract%2FMED%2F22859203

http://europepmc.org/abstract/MED/22859203Abstract One of the greatest sources of uncertainty for future climate predictions is the response of the global carbon cycle to climate change. Although approximately one-half of total CO(2) emissions is at present taken up by combined land and ocean carbon reservoirs, models predict a decline in future carbon uptake by these reservoirs, resulting in a positive carbon-climate feedback. Several recent studies suggest that rates of carbon uptake by the land and ocean have remained constant or declined in recent decades. Other work, however, has called into question the reported decline. Here we use global-scale atmospheric CO(2) measurements, CO(2) emission inventories and their full range of uncertainties to calculate changes in global CO(2) sources and sinks during the past 50 years. Our mass balance analysis shows that net global carbon uptake has increased significantly by about 0.05 billion tonnes of carbon per year and that global carbon uptake doubled, from 2.465±650.8 to 5.065±650.9 billion tonnes per year, between 1960 and 2010. Therefore, it is very unlikely that both land and ocean carbon sinks have decreased on a global scale. Since 1959, approximately 350 billion tonnes of carbon have been emitted by humans to the atmosphere, of which about 55 per cent has moved into the land and oceans. Thus, identifying the mechanisms and locations responsible for increasing global carbon uptake remains a critical challenge in constraining the modern global carbon budget and predicting future carbon-climate interactions.

Boden T. A., G. Marland , and R. J. Andres, 2011: Global,regional, and national fossil-fuel CO₂ emissions. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U. S. Department of Energy, Oak Ridge, Tenn., U. S. A., doi: 10.3334/CDIAC/00001_V2011.890905a37fd51beba4f4b5bffd1b13ec

http%3A%2F%2Fcdiac.ornl.gov%2Ftrends%2Femis%2Foverview

http://cdiac.ornl.gov/trends/emis/overviewPublications containing historical energy statistics make it possible to estimate fossil fuel COemissions back to 1751. Etemad et al. (1991) published a summary compilation that tabulates coal, brown coal, peat, and crude oil production by nation and year. Footnotes in the Etemad et al.(1991) publication extend the energy statistics time series back to 1751. Summary compilations of fossil fuel trade were published by Mitchell (1983, 1992, 1993, 1995). Mitchell's work tabulates solid and liquid fuel imports and exports by nation and year. These pre-1950 production and trade data were digitized and COemission calculations were made following the procedures discussed in Marland and Rotty (1984) and Boden et al. (1995). Further details on the contents and processing of the historical energy statistics are provided in Andres et al. (1999).

Boer G. J., V. K. Arora, 2009: Temperature and concentration feedbacks in the carbon cycle. Geophys. Res. Lett., 36,L02704, doi: 10.1029/2008GL036220.

Boer G. J., V. K. Arora, 2013: Feedbacks in emission-driven and concentration-driven global carbon budgets. J.Climate, 26, 3326- 3341.10.1175/JCLI-D-12-00365.1

993be91c87d6c1e01dfd64111e52592d

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F258795724_Feedbacks_in_Emission-Driven_and_Concentration-Driven_Global_Carbon_Budgets

http://www.researchgate.net/publication/258795724_Feedbacks_in_Emission-Driven_and_Concentration-Driven_Global_Carbon_BudgetsEmissions of CO2 into the atmosphere affect the carbon budgets of the land and ocean as biogeochemical processes react to increased CO2 concentrations. Biogeochemical processes also react to changes in temperature and other climate parameters. This behavior is characterized in terms of carbon-concentration and carbon-climate feedback parameters. The results of this study include 1) the extension of the direct carbon feedback formalism of Boer and Arora to include results from radiatively coupled simulations, as well as those from the biogeochemically coupled and fully coupled simulations used in earlier analyses; 2) a brief analysis of the relationship between this formalism and the integrated feedback formalism of Friedlingstein et al.; 3) the feedback analysis of simulations based on each of the representative concentration pathways (RCPs) RCP2.6, RCP4.5, and RCP8.5; 4) a comparison of the effects of specifying atmospheric CO2 concentrations or CO2 emissions; and 5) the quantification of the relative importance of the two feedback mechanisms in terms of their cumulative contribution to the change in atmospheric CO2. Feedback results are broadly in agreement with earlier studies in that carbon-concentration feedback is negative for the atmosphere and carbon-climate feedback is positive. However, the magnitude and evolution of feedback behavior depends on the formalism employed, the scenario considered, and the specification of CO2 from emissions or as atmospheric concentrations. Both feedback parameters can differ by factors of two or more, depending on the scenario and on the specification of CO2 emissions or concentrations. While feedback results are qualitatively useful and illustrative of carbon budget behavior, they apply quantitatively to particular scenarios and cases.

Brohan P., J. J. Kennedy, I. Harris, S. F. B. Tett, and P. D. Jones, 2006: Uncertainty estimates in regional and global observed temperature changes: A new data set from 1850. J. Geophys. Res., 111,D12106, doi: 10.1029/2005JD006548.10.1029/2005JD006548

7af8b0918e2d7a885a9114718b2a32d8

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2005JD006548%2Fabstract

http://onlinelibrary.wiley.com/doi/10.1029/2005JD006548/abstractABSTRACT The historical surface temperature data set HadCRUT provides a record of surface temperature trends and variability since 1850. A new version of this data set, HadCRUT3, has been produced, benefiting from recent improvements to the sea surface temperature data set which forms its marine component, and from improvements to the station records which provide the land data. A comprehensive set of uncertainty estimates has been derived to accompany the data: Estimates of measurement and sampling error, temperature bias effects, and the effect of limited observational coverage on large-scale averages have all been made. Since the mid twentieth century the uncertainties in global and hemispheric mean temperatures are small, and the temperature increase greatly exceeds its uncertainty. In earlier periods the uncertainties are larger, but the temperature increase over the twentieth century is still significantly larger than its uncertainty.

Canadell J.G., Coauthors, 2007: Contributions to accelerating atmospheric CO₂ growth from economic activity,carbon intensity, and efficiency of natural sinks. Proc. Natl. Acad. Sci. U. S. A., 104, 18 866- 18 870.a1e239d7-521e-4977-b638-ad90cd90ac9a

7791b1db1ec7e90b9fdd28d1044704c3

http%3A%2F%2Fciteseer.ist.psu.edu%2Fshowciting%3Fcid%3D9640069

refpaperuri:(d5ebbe675d2abb677f23df703b7205e0)

http://citeseer.ist.psu.edu/showciting?cid=9640069

Cao,L., Coauthors, 2009: The role of ocean transport in the uptake of anthropogenic CO₂. Biogeosciences, 6, 375- 390.

Chatterjee S., A. S. Hadi, 2006: Regression Analysis by Example. 4th ed., Wiley & Sons, 408 pp.10.1080/02664763.2013.817041

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http%3A%2F%2Fwww.tandfonline.com%2Fdoi%2Fabs%2F10.1080%2F02664763.2013.817041

http://www.tandfonline.com/doi/abs/10.1080/02664763.2013.817041No abstract is available for this item.

Conway T. J., P. P. Tans, L. S. Waterman, K. W. Thoning, D. R. Kitzis, K. A. Masaarie, and N. Zhang, 1994: Evidence for interannual variability of the carbon cycle from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory global air sampling network. J. Geophys. Res., 99, 22 831- 22 855.10.1029/94JD01951

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F94JD01951%2Ffull

refpaperuri:(076553d70f8d4c868ca03cecbd7cd4ea)

http://onlinelibrary.wiley.com/doi/10.1029/94JD01951/fullABSTRACT The distribution and variations of atmospheric CO2 from 1981 to 1992 were determined by measuring CO2 mixing ratios in samples collected weekly at a cooperative global air sampling network. The results constitute the most geographically extensive, carefully calibrated, internally consistent CO2 data set available. Analysis of the data reveals that the global CO2 growth rate has declined from a peak of ~2.5 ppm yr-1 in 1987-1988 to ~0.6 ppm yr-1 in 1992. In 1992 we find no increase in atmospheric CO2 from 30 to 90N. Variations in fossil fuel CO2 emissions cannot explain this result. The north pole-south pole CO2 difference increased from ~3 ppm during 1981-1987 to ~4 ppm during 1988-1991. In 1992 the difference was again ~3 ppm. A two-dimensional model analysis of the data indicates that the low CO2 growth rate in 1992 is mainly due to an increase in the northern hemisphere CO2 sink from 3.0 Gt C yr-1 in 1991 to 5.0 Gt C yr-1 in 1992. The increase in the north pole-south pole CO2 difference appears to result from an increase in the southern hemisphere CO2 sink from ~0.5 to ~1.5 Gt C yr-1.

Cox P. M., D. Pearson, B. B. Booth, P. Friedlingstein, C. Huntingford, C. D. Jones, and C. M. Luke, 2013: Sensitivity of tropical carbon to climate change constrained by carbon dioxide variability. Nature, 494, 341- 344.10.1038/nature11882

23389447

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http%3A%2F%2Fwww.nature.com%2Fnature%2Fjournal%2Fv494%2Fn7437%2Fabs%2Fnature11882.html

http://www.nature.com/nature/journal/v494/n7437/abs/nature11882.htmlThe release of carbon from tropical forests may exacerbate future climate change, but the magnitude of the effect in climate models remains uncertain. Coupled climate-carbon-cycle models generally agree that carbon storage on land will increase as a result of the simultaneous enhancement of plant photosynthesis and water use efficiency under higher atmospheric CO(2) concentrations, but will decrease owing to higher soil and plant respiration rates associated with warming temperatures. At present, the balance between these effects varies markedly among coupled climate-carbon-cycle models, leading to a range of 330 gigatonnes in the projected change in the amount of carbon stored on tropical land by 2100. Explanations for this large uncertainty include differences in the predicted change in rainfall in Amazonia and variations in the responses of alternative vegetation models to warming. Here we identify an emergent linear relationship, across an ensemble of models, between the sensitivity of tropical land carbon storage to warming and the sensitivity of the annual growth rate of atmospheric CO(2) to tropical temperature anomalies. Combined with contemporary observations of atmospheric CO(2) concentration and tropical temperature, this relationship provides a tight constraint on the sensitivity of tropical land carbon to climate change. We estimate that over tropical land from latitude 30掳 north to 30掳 south, warming alone will release 53 -17 gigatonnes of carbon per kelvin. Compared with the unconstrained ensemble of climate-carbon-cycle projections, this indicates a much lower risk of Amazon forest dieback under CO(2)-induced climate change if CO(2) fertilization effects are as large as suggested by current models. Our study, however, also implies greater certainty that carbon will be lost from tropical land if warming arises from reductions in aerosols or increases in other greenhouse gases.

Davidson E. A., I. A. Janssens, 2006: Temperature sensitivity of soil carbon decomposition and feedbacks to climate change. Nature, 440, 165- 173.10.1038/nature04514

16525463

6b30bb2a2aad19612012328c9c1ebf6f

http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM16525463

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM16525463Significantly more carbon is stored in the world's soils--including peatlands, wetlands and permafrost--than is present in the atmosphere. Disagreement exists, however, regarding the effects of climate change on global soil carbon stocks. If carbon stored belowground is transferred to the atmosphere by a warming-induced acceleration of its decomposition, a positive feedback to climate change would occur. Conversely, if increases of plant-derived carbon inputs to soils exceed increases in decomposition, the feedback would be negative. Despite much research, a consensus has not yet emerged on the temperature sensitivity of soil carbon decomposition. Unravelling the feedback effect is particularly difficult, because the diverse soil organic compounds exhibit a wide range of kinetic properties, which determine the intrinsic temperature sensitivity of their decomposition. Moreover, several environmental constraints obscure the intrinsic temperature sensitivity of substrate decomposition, causing lower observed 'apparent' temperature sensitivity, and these constraints may, themselves, be sensitive to climate.

Enting I. G., 1987: A modelling spectrum for carbon cycle studies. Mathematics and Computers in Simulation, 29, 75- 85.10.1016/0378-4754(87)90099-1

ae990227abdfb8bec170c07c32e1266f

http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2F0378475487900991

http://www.sciencedirect.com/science/article/pii/0378475487900991ABSTRACT The concept of a spectrum of mathematical modelling covering varying degrees of inductive versus deductive modelling is used to characterise a range of studies of the global carbon cycle. Low resolution carbon cycle models are considered as examples of models from the middle of the spectrum. It is suggested that such models should be calibrated using techniques similar to ridge regression. By varying the ridge parameter it is possible to explore the consequences of decisions concerning the relative importance of deductive versus inductive aspects of the model calibration.

Enting I. G., J. V. Mansbridge, 1987: Inversion relations for the deconvolution of CO₂ data from ice cores. Inverse Problems, 3, L63- L69.

Enting I. G., T. M. L. Wigley, and M. Heimann, 1994: Future emissions and concentrations of carbon dioxide: Key ocean/ atmosphere/land analyses. CSIRO Division of Atmospheric Research Technical Paper 31, CSIRO, Australia, 127 pp.4281151bdec431fcc769299e4852c5b5

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F228608466_Future_emissions_and_concentrations_of_carbon_dioxide_Key_oceanatmosphereland_analyses

http://www.researchgate.net/publication/228608466_Future_emissions_and_concentrations_of_carbon_dioxide_Key_oceanatmosphereland_analysesVarious projections of the relation between future CO3/4 concentrations and future emissions were undertaken as part of the scientific assessment for Working Group 1 of the Intergov- ernmental Panel on Climate Change. There were three types of calculation: (i) forward pro- jections, calculating the atmospheric CO3/4 concentrations resulting from specified emission scenarios, (ii) inverse calculations determining the emission rates that would be required to achieve stabilisation of CO3/4 concentrations via specified pathways and (iii) impulse re- sponse function calculations required for determining Global Warming Potentials.The use of a standardised set of conditions allows an intercomparison of models. Sensitivity studies explore other aspects of the uncertainties of such projections. This report documents the specifications, the models that were used and the results that were obtained. Some preliminary interpretations of the results are included.

Etheridge D. M., L. P. Steele, R. L. Langenfelds, R. J. Francey, J.-M. Barnola, and V. I. Morgan, 1996: Natural and anthropogenic changes in atmospheric CO₂ over the last 1000 years from air in Antarctic ice and firn. J. Geophys. Res., 101, 4115- 4128.10.1029/95JD03410

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F95JD03410%2Fpdf

refpaperuri:(b84faf4ca6261db43edf5572b5720532)

http://onlinelibrary.wiley.com/doi/10.1029/95JD03410/pdfA record of atmospheric CO 2 mixing ratios from 1006 A.D. to 1978 A.D. has been produced by analysing the air enclosed in three ice cores from Law Dome, Antarctica. The enclosed air has unparalleled age resolution and extends into recent decades, because of the high rate of snow accumulation at the ice core sites. The CO 2 data overlap with the record from direct atmospheric measurements for up to 20 years. The effects of diffusion in the firn on the CO 2 mixing ratio and age of the ice core air were determined by analyzing air sampled from the surface down to the bubble close-off depth. The uncertainty of the ice core CO 2 mixing ratios is 1.2 ppm (1 σ). Preindustrial CO 2 mixing ratios were in the range 275–284 ppm, with the lower levels during 1550–1800 A.D., probably as a result of colder global climate. Natural CO 2 variations of this magnitude make it inappropriate to refer to a single preindustrial CO 2 level. Major CO 2 growth occurred over the industrial period except during 1935–1945 A.D. when CO 2 mixing ratios stabilized or decreased slightly, probably as a result of natural variations of the carbon cycle on a decadal timescale.

Frank D. C., J. Esper, C. C. Raible, U. B ntgen V. Trouet, B. Stocker, and F. Joos, 2010: Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate. Nature, 463, 527- 530.

Friedlingstein P., Coauthors, 2006: Climate-carbon cycle feedback analysis: results from the C⁴MIP model intercomparison. J.Climate, 19, 3337- 3353.10.1175/JCLI3800.1

5d59b504-fbbc-4bf3-8a51-b8eeba186539

e0a5293a1abf86ef678962248aff9172

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F42088984_Climate-carbon_cycle_feedback_analysis_Results_from_the_%28CMIP%29-M-4_model_intercomparison%3Fev%3Dprf_cit

refpaperuri:(e018d0ed39c9cf584af86d789b7b1e92)

http://www.researchgate.net/publication/42088984_Climate-carbon_cycle_feedback_analysis_Results_from_the_(CMIP)-M-4_model_intercomparison?ev=prf_citThe environment is a hot topic in the press and classrooms and much has been said about the need for action to protect our planet. Education plays a crucial role in raising awareness of environmental challenges and shaping the attitudes and behaviours that can make a difference. Our natural world at risk Scientists are concerned about changes in climate that alter the composition of the global atmosphere which can be attributed directly or indirectly to human activity (UNFCC, 2014). If current trends continue, the concentration of Green House Gases (GHGs) in the atmosphere would reach 685 parts per million (ppm) by 2050 (see Figure 1). This would be far above the 450 ppm threshold established by the 2010 United Nations Framework Convention on Climate Change and would lead to a global average temperature increase between 3 and 6 degrees Celsius (OECD, 2013).

Fr枚licher T.L., F. Joos, C. C. Raible, J. L. Sarmiento, 2013: Atmospheric CO₂ response to volcanic eruptions: the role of ENSO, season, and variability. Global Biogeochemical Cycles, 27, 239- 251.10.1002/gbc.20028

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WOS:000318275300022

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http%3A%2F%2Fboris.unibe.ch%2F47699%2F

refpaperuri:(e671fd1e9c13dd03a65f5526055c1cde)

http://boris.unibe.ch/47699/Tropical explosive volcanism is one of the most important natural factors that significantly impact the climate system and the carbon cycle on annual to multi-decadal time scales. The three largest explosive eruptions in the last 50 years-Agung, El Chichon, and Pinatubo-occurred in spring/summer in conjunction with El Nino events and left distinct negative signals in the observational temperature and CO2 records. However, confounding factors such as seasonal variability and El Nino-Southern Oscillation (ENSO) may obscure the forcing-response relationship. We determine for the first time the extent to which initial conditions, i.e., season and phase of the ENSO, and internal variability influence the coupled climate and carbon cycle response to volcanic forcing and how this affects estimates of the terrestrial and oceanic carbon sinks. Ensemble simulations with the Earth System Model (Climate System Model 1.4-carbon) predict that the atmospheric CO2 response is (similar to)60% larger when a volcanic eruption occurs during El Nino and in winter than during La Nina conditions. Our simulations suggest that the Pinatubo eruption contributed 11 +/- 6% to the 25 Pg terrestrial carbon sink inferred over the decade 1990-1999 and -2 +/- 1% to the 22 Pg oceanic carbon sink. In contrast to recent claims, trends in the airborne fraction of anthropogenic carbon cannot be detected when accounting for the decadal-scale influence of explosive volcanism and related uncertainties. Our results highlight the importance of considering the role of natural variability in the carbon cycle for interpretation of observations and for data-model intercomparison.

Gloor M., J. L. Sarmiento, and N. Gruber, 2010: What can be learned about carbon cycle climate feedbacks from the CO2 airborne fraction? Atmospheric Chemistry and Physics, 10, 7739- 7751.10.5194/acpd-10-9045-2010

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http%3A%2F%2Fwww.oalib.com%2Fpaper%2F2702151

refpaperuri:(c179410052803ae8cd01c7f0b2ae3510)

http://www.oalib.com/paper/2702151The ratio of CO2 accumulating in the atmosphere to the CO2 flux into the atmosphere due to human activity, the airborne fraction (AF), is central to predict changes in earth's surface temperature due to greenhouse gas induced warming. This ratio has remained remarkably constant in the past five decades, but recent studies have reported an apparent increasing trend and interpreted it as an indication for a decrease in the efficiency of the combined sinks by the ocean and terrestrial biosphere. We investigate here whether this interpretation is correct by analyzing the processes that control long-term trends and decadal-scale variations in AF. To this end, we use simplified linear models for describing the time evolution of an atmospheric CO2 perturbation. We find firstly that the spin-up time of the system for the AF to converge to a constant value is on the order of 200鈥300 years and differs depending on whether exponentially increasing fossil fuel emissions only or the sum of fossil fuel and land use emissions are used. We find secondly that the primary control on the decadal time-scale variations of the AF is variations in the relative growth rate of the total anthropogenic CO2 emissions. Changes in sink efficiencies tend to leave a smaller imprint. Before interpreting trends in the AF as indication of weakening carbon sink efficiency, it is therefore necessary to account for these trends and variations, which can be achieved based on a predictive equation for the AF implied by the simple models. Using atmospheric CO2 data and emission estimates for the period 1959 through 2006 we find that those controls on the AF, omissions in land use emissions and extrinsic forcing events can explain the observed trend, so that claims for a decreasing trend in the carbon sink efficiency over the last few decades are unsupported by atmospheric CO2 data and anthropogenic emissions estimates.

Gordon L. I., L. B. Jones, 1973: The effect of temperature on carbon dioxide partial pressures in seawater. Marine Chemistry, 1, 317- 322.10.1016/0304-4203(73)90021-2

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http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2F0304420373900212

http://www.sciencedirect.com/science/article/pii/0304420373900212ABSTRACT A correction formula is theoretically derived to evaluate the change in partial pressure of carbon dioxide in seawater upon heating. The constraints on the heating process are constant salinity, total alkalinity, and total carbon dioxide concentration. The result is . This equation fits δPCO2/δt for open ocean seawater compositions to within approximately 9%. The almost constant 4.4%/°C effect is in agreement with that measured by Kanwisher (1960).

Graven H.D., Coauthors, 2013: Enhanced seasonal exchange of CO₂ by northern ecosystems since 1960. Science, 341, 1085-1089, doi: 10.1126/science.1239207.10.1126/science.1239207

23929948

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http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM23929948

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM23929948Seasonal variations of atmospheric carbon dioxide (CO2) in the Northern Hemisphere have increased since the 1950s, but sparse observations have prevented a clear assessment of the patterns of long-term change and the underlying mechanisms. We compare recent aircraft-based observations of CO2 above the North Pacific and Arctic Oceans to earlier data from 1958 to 1961 and find that the seasonal amplitude at altitudes of 3 to 6 km increased by 50% for 45° to 90°N but by less than 25% for 10° to 45°N. An increase of 30 to 60% in the seasonal exchange of CO2 by northern extratropical land ecosystems, focused on boreal forests, is implicated, substantially more than simulated by current land ecosystem models. The observations appear to signal large ecological changes in northern forests and a major shift in the global carbon cycle.

Hansen J., R. Ruedy, J. Glascoe, and M. Sato, 1999: GISS analysis of surface temperature change. J. Geophys. Res., 104, 30 997- 31 022.10.1029/1999JD900835

739f664db1de69c4fbde35a08320f21e

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F1999JD900835%2Ffull

http://onlinelibrary.wiley.com/doi/10.1029/1999JD900835/fullWe describe the current GISS analysis of surface temperature change for the period 1880–1999 based primarily on meteorological station measurements. The global surface temperature in 1998 was the warmest in the period of instrumental data. The rate of temperature change was higher in the past 25 years than at any previous time in the period of instrumental data. The warmth of 1998 was too large and pervasive to be fully accounted for by the recent El Nino. Despite cooling in the first half of 1999, we suggest that the mean global temperature, averaged over 2–3 years, has moved to a higher level, analogous to the increase that occurred in the late 1970s. Warming in the United States over the past 50 years has been smaller than in most of the world, and over that period there was a slight cooling trend in the eastern United States and the neighboring Atlantic Ocean. The spatial and temporal patterns of the temperature change suggest that more than one mechanism was involved in this regional cooling. The cooling trend in the United States, which began after the 1930s and is associated with ocean temperature change patterns, began to reverse after 1979. We suggest that further warming in the United States to a level rivaling the 1930s is likely in the next decade, but reliable prediction requires better understanding of decadal oscillations of ocean temperature.

Hansen J., M. Sato, R. Ruedy, K. Lo, D. W. Lea, and M. Medina-Elizade, 2006: Global temperature change. Proc. Natl. Acad. Sci. U. S. A., 103, 14 288- 14 293.

Houghton R. A., 2003: Revised estimates of the annual net flux of carbon to the atmosphere from changes in land use and land management 1850-2000. Tellus B, 55, 378- 390.10.1034/j.1600-0889.2003.01450.x

c2d0e262e66233ae9c7530795653ad10

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1034%2Fj.1600-0889.2003.01450.x%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0889.2003.01450.x/pdfABSTRACT

IPCC, 1996: Climate Change 1995: The Science of Climate Change. Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change. J. T. Houghton et al.,Eds., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 572 pp.

IPCC, 2001: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. J. T. Houghton et al.,Eds., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 881 pp.

IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. T. F. Stocker et al.,Eds., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.

Jarvis J. A., P. C. Young, D. T. Leedal, and A. Chotai, 2008: A robust sequential CO₂ emissions strategy based on optimal control of atmospheric CO₂ concentrations. Climatic Change, 86, 357- 373.

Jones C. D., P. M. Cox, 2005: On the significance of atmospheric CO₂ growth rate anomalies in 2002-2003. Geophys. Res. Lett., 32, L14816, doi: 10.1029/2005/GL023027.

Jones P. D., A. Moberg, 2003: Hemispheric and large-scale surface air temperature variations: An extensive revision and an update to 2001. J.Climate, 16, 206- 223.

Joos F., M. Bruno, R. Fink, U. Sigenthaler, T. F. Stocker, C. Le Qur, and J. L. Sarmiento, 1996: An efficient and accurate representation of complex oceanic and biospheric models of anthropogenic carbon uptake. Tellus, 48B, 397- 417.

Joos F., G.-K. Plattner, T. F. Stocker, O. Marchal, and A. Schmittner, 1999: Global warming and marine carbon cycle feedbacks on future atmospheric CO₂. Science, 284, 464- 467.

Joos F., I. C. Prentice, S. Sitch, R. Meyer, G. Hooss, G.-K. Plattner, S. Gerber, and K. Hasselmann, 2001: Global warming feedbacks on terrestrial carbon uptake under the Intergovernmental Panel on Climate Change (IPCC) emission scenarios. Global Biogeochemical Cycles, 4, 891- 907.

Joos F., Coauthors, 2013: Carbon dioxide and climate impulse response functions for the computation of greenhouse gas metrics: A multi-model analysis. Atmospheric Chemistry and Physics, 13, 2793- 2825.10.5194/acp-13-2793-2013

e0fc0105c12016d84a92312f02a94915

http%3A%2F%2Fwww.oalib.com%2Fpaper%2F1370767

http://www.oalib.com/paper/1370767The responses of carbon dioxide (CO2) and other climate variables to an emission pulse of CO2 into the atmosphere are often used to compute the Global Warming Potential (GWP) and Global Temperature change Potential (GTP), to characterize the response timescales of Earth System models, and to build reduced-form models. In this carbon cycle-climate model intercomparison project, which spans the full model hierarchy, we quantify responses to emission pulses of different magnitudes injected under different conditions. The CO2 response shows the known rapid decline in the first few decades followed by a millennium-scale tail. For a 100 Gt-C emission pulse added to a constant CO2 concentration of 389 ppm, 25 ± 9% is still found in the atmosphere after 1000 yr; the ocean has absorbed 59 ± 12% and the land the remainder (16 ± 14%). The response in global mean surface air temperature is an increase by 0.20 ± 0.12 °C within the first twenty years; thereafter and until year 1000, temperature decreases only slightly, whereas ocean heat content and sea level continue to rise. Our best estimate for the Absolute Global Warming Potential, given by the time-integrated response in CO2 at year 100 multiplied by its radiative efficiency, is 92.5 × 10 15 yr W m 2 per kg-CO2. This value very likely (5 to 95% confidence) lies within the range of (68 to 117) × 10 15 yr W m 2 per kg-CO2. Estimates for time-integrated response in CO2 published in the IPCC First, Second, and Fourth Assessment and our multi-model best estimate all agree within 15% during the first 100 yr. The integrated CO2 response, normalized by the pulse size, is lower for pre-industrial conditions, compared to present day, and lower for smaller pulses than larger pulses. In contrast, the response in temperature, sea level and ocean heat content is less sensitive to these choices. Although, choices in pulse size, background concentration, and model lead to uncertainties, the most important and subjective choice to determine AGWP of CO2 and GWP is the time horizon.

Keeling C. D., T. P. Whorf, M. Wahlen, and J. van der Plicht, 1995: Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980. Nature, 375, 666- 670.7bd59571c3aefdde97c31f1c063e373f

http%3A%2F%2Ftreephys.oxfordjournals.org%2Fexternal-ref%3Faccess_num%3D10.1038%2F375666a0%26link_type%3DDOI

http://treephys.oxfordjournals.org/external-ref?access_num=10.1038/375666a0&link_type=DOI

Keenan T. F., D. Y Holligner, G. Bohrer, D. Dragoni, J. W. Munger, H. P. Schmid, and A. D. Richardson, 2013: Increase in forest water-use efficiency as atmospheric carbon dioxide concentrations rise. Nature, 499, 324- 327.10.1038/nature12291

23842499

af6edb191590fe178e7d5b835204b256

http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM23842499

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM23842499Terrestrial plants remove CO2 from the atmosphere through photosynthesis, a process that is accompanied by the loss of water vapour from leaves. The ratio of water loss to carbon gain, or water-use efficiency, is a key characteristic of ecosystem function that is central to the global cycles of water, energy and carbon. Here we analyse direct, long-term measurements of whole-ecosystem carbon and water exchange. We find a substantial increase in water-use efficiency in temperate and boreal forests of the Northern Hemisphere over the past two decades. We systematically assess various competing hypotheses to explain this trend, and find that the observed increase is most consistent with a strong CO2 fertilization effect. The results suggest a partial closure of stomata-small pores on the leaf surface that regulate gas exchange-to maintain a near-constant concentration of CO2 inside the leaf even under continually increasing atmospheric CO2 levels. The observed increase in forest water-use efficiency is larger than that predicted by existing theory and 13 terrestrial biosphere models. The increase is associated with trends of increasing ecosystem-level photosynthesis and net carbon uptake, and decreasing evapotranspiration. Our findings suggest a shift in the carbon- and water-based economics of terrestrial vegetation, which may require a reassessment of the role of stomatal control in regulating interactions between forests and climate change, and a re-evaluation of coupled vegetation-climate models.

Khalil H. K., 2001: Nonlinear Systems.3rd ed., Princeton Hall, 750 pp.

Knorr W., 2009: Is the airborne fraction of anthropogenic CO₂ emissions increasing?. Geophys. Res. Lett., 36, L21710, doi: 10.1029/2009GL040613.bce22d0af2105e0153bb7711859e3afd

http%3A%2F%2Fresearch-information.bristol.ac.uk%2Fen%2Fpublications%2Fis-the-airborne-fraction-of-anthropogenic-co2-increasing%28dbcf8eaa-eac8-4575-8b47-b3fe780d399e%29.html

http://research-information.bristol.ac.uk/en/publications/is-the-airborne-fraction-of-anthropogenic-co2-increasing(dbcf8eaa-eac8-4575-8b47-b3fe780d399e).html

Körner C., J. A. Arnone III, 1992: Responses to elevated carbon dioxide in artificial tropical ecosystems. Science, 257, 1672- 1675.10.1126/science.257.5077.1672

17841166

96f12be3f41a290051e62c4e84c037b6

http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM17841166

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM17841166Carbon, nutrient, and water balance as well as key plant and soil processes were simultaneously monitored for humid tropical plant communities treated with CO(2)-enriched atmospheres. Despite vigorous growth, no significant differences in stand biomass (of both the understory and overstory), leaf area index, nitrogen or water consumption, or leaf stomatal behavior were detected between ambient and elevated CO(2) treatments. Major responses under elevated CO(2) included massive starch accumulation in the tops of canopies, increased fine-root production, and a doubling of CO(2) evolution from the soil. Stimulated rhizosphere activity was accompanied by increased loss of soil carbon and increased mineral nutrient leaching. This study points at the inadequacy of scaling-up from physiological baselines to ecosystems without accounting for interactions among components, and it emphasizes the urgent need for whole-system experimental approaches in global-change research.

Le Quéré, C., Coauthors, 2009: Trends in the sources and sinks of carbon dioxide. Nature Geoscience, 2, 831- 836.10.1038/ngeo689

acc5604e8447d70896ed4cfae06d1197

http%3A%2F%2Fwww.nature.com%2Fngeo%2Fjournal%2Fv2%2Fn12%2Fabs%2Fngeo689.html

http://www.nature.com/ngeo/journal/v2/n12/abs/ngeo689.htmlABSTRACT Efforts to control climate change require the stabilization of atmospheric CO2 concentrations. This can only be achieved through a drastic reduction of global CO2 emissions. Yet fossil fuel emissions increased by 29% between 2000 and 2008, in conjunction with increased contributions from emerging economies, from the production and international trade of goods and services, and from the use of coal as a fuel source. In contrast, emissions from land-use changes were nearly constant. Between 1959 and 2008, 43% of each year's CO2 emissions remained in the atmosphere on average; the rest was absorbed by carbon sinks on land and in the oceans. In the past 50 years, the fraction of CO2 emissions that remains in the atmosphere each year has likely increased, from about 40% to 45%, and models suggest that this trend was caused by a decrease in the uptake of CO2 by the carbon sinks in response to climate change and variability. Changes in the CO2 sinks are highly uncertain, but they could have a significant influence on future atmospheric CO2 levels. It is therefore crucial to reduce the uncertainties.

Lemoine D. M., 2010: Paleoclimatic warming increased carbon dioxide concentrations. J. Geophys. Res., 115, doi: 10.1029/ 2010JD014725.10.1029/2010JD014725

ee3ed1e57aa0b04e6ea12a8d10245a88

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2010JD014725%2Fabstract

http://onlinelibrary.wiley.com/doi/10.1029/2010JD014725/abstract[1] If climate-carbon feedbacks are positive, then warming causes changes in carbon dioxide (CO 2 ) sources and sinks that increase CO 2 concentrations and create further warming. Previous work using paleoclimatic reconstructions has not disentangled the causal effect of interest from the effects of reverse causality and autocorrelation. The response of CO 2 to variations in orbital forcing over the past 800,000 years suggests that millennial-scale climate-carbon feedbacks are significantly positive and significantly greater than century-scale feedbacks. Feedbacks are also significantly greater on 100 year time scales than on 50 year time scales over the past 1500 years. Posterior probability distributions implied by coupled models' predictions and by these paleoclimatic results give a mean of 0.03 for the nondimensional climate-carbon feedback factor and a 90% chance of its being between 0.04 and 0.09. The 70% chance that climate-carbon feedbacks are positive implies that temperature change projections tend to underestimate an emission path's consequences if they do not allow the carbon cycle to respond to changing temperatures.

Lenton T. M., 2000: Land and ocean carbon cycle feedback effects on global warming in a simple Earth system model. Tellus B, 52, 1159- 1188.10.3402/tellusb.v52i5.17097

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1034%2Fj.1600-0889.2000.01104.x%2Fcitedby

http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0889.2000.01104.x/citedbyA simple Earth system model is developed by coupling a box model of the global carbon cycle to an energy‐balance approximation of global temperature. The model includes a range of feedback mechanisms between atmospheric CO 2 , surface temperature and land and ocean carbon cycling. It is used to assess their effect on the global change being driven by anthropogenic CO 2 emissions from fossil fuel burning and land‐use change. When tuned to reach the 1990 level of atmospheric CO 2 , the model CO 2 predictions for 1832–1990 are reasonably close to ice‐core and instrumental records, observed global warming of 650.665K from 1860–1990 is accurately predicted and the land and ocean carbon sinks for the 1980s are close to IPCC central estimates. The ocean sink is reduced by 650.365GtC65yr 611 when the ocean surface is assumed to warm at the same rate as global surface temperature. Land and oceanic carbon sinks are predicted to be growing at present and hence buffering the rate of rise of atmospheric CO 2 . In the basic model, the current land carbon sink is assumed to be due to CO 2 fertilisation of photosynthesis. The slight warming that has occurred enhances soil respiration (carbon loss) and net primary productivity (carbon uptake) by similar amounts. When the model is forced with a “business as usual”(IS92a) emissions scenario for 1990–2100 followed by a linear decline in emissions to zero at 2200, CO 2 reaches a peak of 98565ppmv in 2170 and temperature peaks at +5.565K in 2180. Peak CO 2 is 6513565ppmv higher than suggested by IPCC for the same forcing, principally because global warming first suppresses the land carbon sink then generates a land carbon source. When warming exceeds 654.565K, soil respiration “overtakes” the CO 2 fertilisation of NPP, triggering a release of 657065GtC from terrestrial ecosystems over 6510065years. When the effects of temperature on photosynthesis, respiration and soil respiration are removed, peak levels of CO 2 are reduced by 6510065ppmv and peak temperature by 650.565K. Distinguishing separate soil carbon pools with different residence times does not significantly alter the timing of the switch to a land carbon source or its effect on peak CO 2 , but it causes the source to persist for longer. If forest re‐growth or nitrogen deposition are assumed to contribute to the current land carbon sink, this implies a weaker CO 2 fertilisation effect on photosynthesis and generates a larger future carbon source. Peak CO 2 levels are also sensitive by about ±8065ppmv to upper and lower limits on the temperature responses of photosynthesis, plant respiration and soil respiration. By forcing the model with a range of future emission scenarios it is found that the creation of a significant land carbon source requires rapid warming, exceeding 654.565K, and its magnitude increases with the rate of forcing. The carbon source is greatest for the most rapid burning of the largest reserve of fossil fuel. It is concluded that carbon loss from terrestrial ecosystems may significantly (6510%) amplify global warming under “business as usual” or more extreme scenarios.

Li S. L., A. J. Jarvis, and D. T. Leedal, 2009: Are response function representations of the global carbon cycle ever interpretable? Tellus B, 61, 361- 371.10.1111/j.1600-0889.2008.00401.x

540f4c3e9a493e3d714c869d9ca50723

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1111%2Fj.1600-0889.2008.00401.x%2Fpdf

http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0889.2008.00401.x/pdfABSTRACT Response function models are often used to represent the behaviour of complex, high order global carbon cycle (GCC) and climate models in applications which require short model run times. Although apparently black-box, these response function models need not necessarily be entirely opaque, but instead may also convey useful insights into the properties of the parent model or process. By exploiting a transfer function (TF) framework to analyse the Lenton GCC model, this paper attempts to demonstrate that response function representations of GCC models can sometimes also provide structural information on the parent model from which they are identified and calibrated. We take a fifth-order TF identified from the impulse response of the Lenton model atmospheric burden, and decompose this to show how it can be re-expresses in a generic five-box form in sympathy with the structure of the parent model.

Long S. P., 1991: Modification of the response of photosynthetic productivity to rising temperature by atmospheric CO₂ concentrations: Has its importance been underestimated? Plant, Cell & Environment, 14, 729- 739.

Long S. P., E. A. Ainswroth, A. Rogers, and D. R. Ort, 2004: Rising atmospheric carbon dioxide: Plants FACE the future. Annual Review of Plant Biology, 55, 591- 628.a645ff32-191c-4b93-a9fe-ed56aabade39

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http%3A%2F%2Fwww.ars.usda.gov%2Fresearch%2Fpublications%2Fpublications.htm%3Fseq_no_115%3D156847%26pf%3D1

refpaperuri:(cccf4aad16ab55401ae34a6718c7426f)

http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=156847&pf=1

L眉thi, D., Coauthors, 2008: High-resolution carbon dioxide concentration record 650, 000-800, 000 years before present. Nature, 453, 379- 382.10.1038/nature06949

18480821

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http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM18480821

refpaperuri:(48b1fff8ff5849fe883d47b9c7b92bb8)

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM18480821Changes in past atmospheric carbon dioxide concentrations can be determined by measuring the composition of air trapped in ice cores from Antarctica. So far, the Antarctic Vostok and EPICA Dome C ice cores have provided a composite record of atmospheric carbon dioxide levels over the past 650,000 years. Here we present results of the lowest 200 m of the Dome C ice core, extending the record of atmospheric carbon dioxide concentration by two complete glacial cycles to 800,000 yr before present. From previously published data and the present work, we find that atmospheric carbon dioxide is strongly correlated with Antarctic temperature throughout eight glacial cycles but with significantly lower concentrations between 650,000 and 750,000 yr before present. Carbon dioxide levels are below 180 parts per million by volume (p.p.m.v.) for a period of 3,000 yr during Marine Isotope Stage 16, possibly reflecting more pronounced oceanic carbon storage. We report the lowest carbon dioxide concentration measured in an ice core, which extends the pre-industrial range of carbon dioxide concentrations during the late Quaternary by about 10 p.p.m.v. to 172-300 p.p.m.v.

Maier-Reimer E., K. Hasselmann, 1987: Transport and storage of CO₂ in the ocean-an inorganic ocean-circulation carbon cycle model. Climate Dyn., 2, 63- 90.10.1007/BF01054491

9a6be46c-79d6-4267-8097-09a82d95b97a

9fcc4bbd30a2a54c058944e59477db5b

http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2FBF01054491

refpaperuri:(47eb873d653aafe71d653bb659e5ed54)

http://link.springer.com/article/10.1007/BF01054491Inorganic carbon in the ocean is modelled as a passive tracer advected by a three-dimensional current field computed from a dynamical global ocean circulation model. The carbon exchange between the ocean and atmosphere is determined directly from the (temperature-dependent) chemical interaction rates in the mixed layer, using a standard CO 2 flux relation at the air-sea interface. The carbon cycle is closed by coupling the ocean to a one-layer, horizontally diffusive atmosphere. Biological sources and sinks are not included. In this form the ocean carbon model contains essentially no free tuning parameters. The model may be regarded as a reference for interpreting numerical experiments with extended versions of the model including biological processes in the ocean (Bacastow R and Maier-Reimer E in prep.) and on land (Esser G et al in prep.). Qualitatively, the model reproduces the principal features of the observed CO 2 distribution bution in the surface ocean. However, the amplitudes of surface pCO 2 are underestimated in upwelling regions by a factor of the order of 1.5 due to the missing biological pump. The model without biota may, nevertheless, be applied to compute the storage capacity of the ocean to first order for anthropogenic CO 2 emissions. In the linear regime, the response of the model may be represented by an impulse response function which can be approximated by a superposition of exponentials with different amplitudes and time constants. This provides a simple reference for comparison with box models. The largest-amplitude (鈭0.35) exponential has a time constant of 300 years. The effective storage capacity of the oceans is strongly dependent on the time history of the anthropogenic input, as found also in earlier box model studies.

Oechel W.C., Coauthors, 1994: Transient nature of CO₂ fertilization in Arctic tundra. Nature, 371, 500- 503.10.1038/371500a0

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http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F232779491_Transient_nature_of_CO2_fertilization_in_Arctic_tundra%3Fev%3Dauth_pub

refpaperuri:(ed7b9e41f169e4f37fed0caf2930d8af)

http://www.researchgate.net/publication/232779491_Transient_nature_of_CO2_fertilization_in_Arctic_tundra?ev=auth_pubABSTRACT THERE has been much debate about the effect of increased atmospheric CO2 concentrations on plant net primary production1,3 and on net ecosystem CO2 flux30210. Apparently conflicting experimental findings could be the result of differences in genetic potential110215 and resource availability160220, different experimental conditions210224 and the fact that many studies have focused on individual components of the system2,21,250227 rather than the whole ecosystem. Here we present results of an in situ experiment on the response of an intact native ecosystem to elevated CO2. An undisturbed patch of tussock tundra at Toolik Lake, Alaska, was enclosed in greenhouses in which the CO2 level, moisture and temperature could be controlled28, and was subjected to ambient (340 p.p.m.) and elevated (680 p.p.m.) levels of CO2 and temperature (+4 °C). Air humidity, precipitation and soil water table were maintained at ambient control levels. For a doubled CO2 level alone, complete homeostasis of the CO2 flux was re-established within three years, whereas the regions exposed to a combination of higher temperatures and doubled CO2 showed persistent fertilization effect on net ecosystem carbon sequestration over this time. This difference may be due to enhanced sink activity from the direct effects of higher temperatures on growth16,290233 and to indirect effects from enhanced nutrient supply caused by increased mineralization10,11,19,27,34. These results indicate that the responses of native ecosystems to elevated CO2 may not always be positive, and are unlikely to be straightforward. Clearly, CO2 fertilization effects must always be considered in the context of genetic limitation, resource availability and other such factors.

Oeschger H., M. Heimann, 1983: Uncertainties of predictions of future atmospheric CO₂ concentrations. J. Geophys. Res., 88, 1258- 1262.10.1029/JC088iC02p01258

fa6392d1b016dbaa8c5ebde521852ab6

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2FJC088iC02p01258%2Fabstract

http://onlinelibrary.wiley.com/doi/10.1029/JC088iC02p01258/abstractLinear carbon cycle models, tuned to reproduce the CO 2 increase observed at Mauna Loa, independently of their individual assumptions, predict almost identical CO 2 concentration trends for fossil energy scenarios assuming a slightly increasing production in the next few decades. The basic information for such prognoses therefore is the airborne fraction observed over the last 20 years. Uncertainties in this quantity are due to possible errors in the estimate of fossil fuel consumption and the corresponding CO 2 emission, possible natural fluctuations in the baseline CO 2 level, and uncertainties regarding the biospheric CO 2 input and uptake as a result of deforestation and reforestation and land management. Depending on different assumptions the effective airborne fraction, defined as the ratio of CO 2 increase due to fossil fuel CO 2 alone to the integrated CO 2 production, might be as low as 0.38 or as high as 0.72, compared to the apparent airborne fraction of 0.55. The effective airborne fraction derived from carbon cycle models, considering only the CO 2 uptake by the ocean, lies in the range 0.60鈥0.70. A value as low as 0.40 seems therefore highly improbable. A high biospheric anthropogenic CO 2 input therefore must have been accompanied by a high CO 2 fertilization effect. Model considerations, however, are not in contradiction with a high biospheric input with the maximum production before 1958, which also would imply low preindustrial CO 2 concentrations in the range 270鈥280 ppm as reported recently.

Piao S.L., Coauthors, 2008: Net carbon dioxide losses of northern ecosystems in response to autumn warming. Nature, 451, 49- 52.10.1038/nature06444

18172494

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http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM18172494

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM18172494The carbon balance of terrestrial ecosystems is particularly sensitive to climatic changes in autumn and spring, with spring and autumn temperatures over northern latitudes having risen by about 1.1 degrees C and 0.8 degrees C, respectively, over the past two decades. A simultaneous greening trend has also been observed, characterized by a longer growing season and greater photosynthetic activity. These observations have led to speculation that spring and autumn warming could enhance carbon sequestration and extend the period of net carbon uptake in the future. Here we analyse interannual variations in atmospheric carbon dioxide concentration data and ecosystem carbon dioxide fluxes. We find that atmospheric records from the past 20 years show a trend towards an earlier autumn-to-winter carbon dioxide build-up, suggesting a shorter net carbon uptake period. This trend cannot be explained by changes in atmospheric transport alone and, together with the ecosystem flux data, suggest increasing carbon losses in autumn. We use a process-based terrestrial biosphere model and satellite vegetation greenness index observations to investigate further the observed seasonal response of northern ecosystems to autumnal warming. We find that both photosynthesis and respiration increase during autumn warming, but the increase in respiration is greater. In contrast, warming increases photosynthesis more than respiration in spring. Our simulations and observations indicate that northern terrestrial ecosystems may currently lose carbon dioxide in response to autumn warming, with a sensitivity of about 0.2 PgC degrees C(-1), offsetting 90% of the increased carbon dioxide uptake during spring. If future autumn warming occurs at a faster rate than in spring, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested.

Rafelski L. E., S. C. Piper, and R. F. Keeling, 2009: Climate effects on atmospheric carbon dioxide over the last century. Tellus B, 61, 718- 731.10.1111/j.1600-0889.2009.00439.x

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1111%2Fj.1600-0889.2009.00439.x%2Fpdf

refpaperuri:(7c4aa04bd53a5e37c5316be31137ebbc)

http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0889.2009.00439.x/pdfThe buildup of atmospheric CO2 since 1958 is surprisingly well explained by the simple premise that 57% of the industrial emissions (fossil fuel burning and cement manufacture) has remained airborne. This premise accounts well for the rise both before and after 1980 despite a decrease in the growth rate of fossil fuel CO2 emissions, which occurred at that time, and by itself should have caused the airborne fraction to decrease. In contrast, the buildup prior to 1958 was not simply proportional to cumulative fossil fuel emissions, and notably included a period during the 1940s when CO2 growth stalled despite continued fossil fuel emissions. Here we show that the constancy of the airborne fraction since 1958 can be in part explained by decadal variations in global land air temperature, which caused a warming-induced release of CO2 from the land biosphere to the atmosphere. We also show that the 1940s plateau may be related to these decadal temperature variations. Furthermore, we show that there is a close connection between the phenomenology producing CO2 variability on multidecadal and El Ni茂驴陆o timescales.

Raupach M. R., J. G. Canadell, and C. Le Qu茅r茅, 2008: Anthropogenic and biophysical contributions to increasing atmospheric CO₂ growth rate and airborne fraction. Biogeosciences, 5, 1601- 1613.10.5194/bg-5-1601-2008

ac7befa9-764e-45e5-afd4-eeb63e01f9a0

e6ff8d4ca43f77ff1faab903df27b58d

http%3A%2F%2Fwww.oalib.com%2Fpaper%2F1375254

refpaperuri:(57069522de69cf103504f90121a83b18)

http://www.oalib.com/paper/1375254We quantify the relative roles of natural and anthropogenic influences on the growth rate of atmospheric CO2 and the CO2 airborne fraction, considering both interdecadal trends and interannual variability. A combined ENSO-Volcanic Index (EVI) relates most (~75%) of the interannual variability in CO2 growth rate to the El-Ni o-Southern-Oscillation (ENSO) climate mode and volcanic activity. Analysis of several CO2 data sets with removal of the EVI-correlated component confirms a previous finding of a detectable increasing trend in CO2 airborne fraction (defined using total anthropogenic emissions including fossil fuels and land use change) over the period 1959鈥2006, at a proportional growth rate 0.24% y 1 with probability ~0.9 of a positive trend. This implies that the atmospheric CO2 growth rate increased slightly faster than total anthropogenic CO2 emissions. To assess the combined roles of the biophysical and anthropogenic drivers of atmospheric CO2 growth, the increase in the CO2 growth rate (1.9% y 1 over 1959鈥2006) is expressed as the sum of the growth rates of four global driving factors: population (contributing +1.7% y 1); per capita income (+1.8% y 1); the total carbon intensity of the global economy ( 1.7% y 1); and airborne fraction (averaging +0.2% y 1 with strong interannual variability). The first three of these factors, the anthropogenic drivers, have therefore dominated the last, biophysical driver as contributors to accelerating CO2 growth. Together, the recent (post-2000) increase in growth of per capita income and decline in the negative growth (improvement) in the carbon intensity of the economy will drive a significant further acceleration in the CO2 growth rate over coming decades, unless these recent trends reverse.

Raupach M.R., Coauthors, 2014: The declining uptake rate of atmospheric CO₂ by land and ocean sinks. Biogeosciences, 11, 3453- 3475.10.5194/bg-11-3453-2014

7c364d1d-e6be-4571-af23-6e812b929eec

f1d8fe9d5db62e29c161b83d99c59857

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F260939332_The_declining_uptake_rate_of_atmospheric_CO2_by_land_and_ocean_sinks

refpaperuri:(40026588c3e3467b6e5c51cea87018b1)

http://www.researchgate.net/publication/260939332_The_declining_uptake_rate_of_atmospheric_CO2_by_land_and_ocean_sinksThrough 1959-2012, an airborne fraction (AF) of 44% of total anthropogenic CO2 emissions remained in the atmosphere, with the rest being taken up by land and ocean CO2 sinks. Understanding of this uptake is critical because it greatly alleviates the emissions reductions required for climate mitigation. An observable quantity that reflects sink properties more directly than the AF is the CO2 sink rate (kS), the combined land-ocean CO2 sink flux per unit excess atmospheric CO2 above preindustrial levels. Here we show from observations that kS declined over 1959-2012 by a factor of about 1/3, implying that CO2 sinks increased more slowly than excess CO2. We attribute the decline in kS to four mechanisms: slower-than-exponential CO2 emissions growth (~ 35% of the trend), volcanic eruptions (~ 25 %), sink responses to climate change (~ 20 %), and nonlinear responses to increasing CO2, mainly oceanic (~ 20 %). The first of these mechanisms is associated purely with extrinsic forcings, and the last two with intrinsic, nonlinear responses of sink processes to changes in climate and atmospheric CO2. Our results indicate that the effects of these intrinsic, nonlinear responses are already detectable in the global carbon cycle. Although continuing future decreases in kS will occur under all plausible CO2 emission scenarios, the rate of decline varies between scenarios in non-intuitive ways because extrinsic and intrinsic mechanisms respond in opposite ways to changes in emissions: extrinsic mechanisms cause kS to decline more strongly with increasing mitigation, while intrinsic mechanisms cause kS to decline more strongly under high-emission, low-mitigation scenarios as the carbon- climate system is perturbed further from a near-linear regime.

Rayner N. A., D. E. Parker, E. B. Horton, C. K. Folland , L. V. Alexand er, D. P. Rowell, E. C. Kent, and A. Kaplan, 2003: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108, doi: 10.1029/2002JD002670.54d9a97d5f4d819ebf37e2a94ff31ecb

http%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.172.4502%26rank%3D3

/s?wd=paperuri%3A%2819e27110466e0495bcd432be6291fa9b%29&filter=sc_long_sign&tn=SE_xueshusource_2kduw22v&sc_vurl=http%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.172.4502%26rank%3D3&ie=utf-8

Rayner P. J., A. Stavert, M. Scholze,A. Ahlstr枚m, C. E. Allison, and R. M. Law, 2015: Recent changes in the global and regional carbon cycle: Analysis of first-order diagnostics. Biogeosciences, 12, 835- 844.10.5194/bg-12-835-2015

2834bafc12bb971a970c2583ee1cf28f

http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F273494758_Recent_changes_in_the_global_and_regional_carbon_cycle_analysis_of_first-order_diagnostics

http://www.researchgate.net/publication/273494758_Recent_changes_in_the_global_and_regional_carbon_cycle_analysis_of_first-order_diagnosticsABSTRACT 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.

Revelle R., H. E. Suess, 1957: Carbon dioxide exchange between atmosphere and ocean and the question of an increase of atmospheric CO₂ during the past decades. Tellus, 9, 18- 27.10.1111/j.2153-3490.1957.tb01849.x

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430747bb6d95767c1b23a4a022ddcce9

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1111%2Fj.2153-3490.1957.tb01849.x%2Fpdf

refpaperuri:(053196ba954727ee69a8cc0eee280e25)

http://onlinelibrary.wiley.com/doi/10.1111/j.2153-3490.1957.tb01849.x/pdfABSTRACT From a comparison of C14/C12 and C13/C12 ratios in wood and in marine material and from a slight decrease of the C14 concentration in terrestrial plants over the past 50 years it can be concluded that the average lifetime of a CO2 molecule in the atmosphere before it is dissolved into the sea is of the order of 10 years. This means that most of the CO2 released by artificial fuel combustion since the beginning of the industrial revolution must have been absorbed by the oceans. The increase of atmospheric CO2 from this cause is at present small but may become significant during future decades if industrial fuel combustion continues to rise exponentially.Present data on the total amount of CO2 in the atmosphere, on the rates and mechanisms of exchange, and on possible fluctuations in terrestrial and marine organic carbon, are inadequate for accurate measurement of future changes in atmospheric CO2. An opportunity exists during the International Geophysical Year to obtain much of the necessary information.

Sarmiento J. L., J. C. Orr, and U. Siegenthaler, 1992: A perturbation simulation of CO₂ uptake in an ocean general circulation model. J. Geophys. Res., 97, 3621- 3645.10.1029/91JC02849

b35a95ef-db6a-4997-98d3-50afa08120d3

38b9268e3e69f01cae283045c34fbb85

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F91JC02849%2Fabstract

refpaperuri:(7289efe9dc3b66cf480a67d37b9f8bfc)

http://onlinelibrary.wiley.com/doi/10.1029/91JC02849/abstractThe uptake of anthropogenic CO 2 by the ocean is simulated using a perturbation approach in a three-dimensional global general circulation model. Atmospheric p CO 2 is prescribed for the period 1750–1990 using the combined Siple ice core and Mauna Loa records. For the period 1980 to 1989, the average flux of CO 2 into the ocean is 1.9 GtC/yr. However the bomb radiocarbon simulation of Toggweiler et al. (1989 b ) shows that the surface to deep ocean exchange in this model is too sluggish. Hence the CO 2 uptake calculated by the model is probably below the actual value. The observed atmospheric increase in 1980 to 1989 is 3.2 GtC/yr, for a combined atmosphere-ocean total of 5.1 GtC/yr. This is comparable to the estimated fossil CO 2 production of 5.4 GtC/yr, implying that other sources and sinks (such as from deforestation, enhanced growth of land biota, and changes in the ocean carbon cycle) must be approximately in balance. The sensitivity of the uptake to the gas exchange rate is small: a 100% increase in gas exchange rate gives only a 9.2% increase in cumulative oceanic uptake. Details of the penetration into different oceanic regions are discussed.

Scheffer M., V. Brovkin, and P. M. Cox, 2006: Positive feedback between global warming and atmospheric CO₂ concentration inferred from past climate change. Geophys. Res. Lett.,33,L10702, doi: 10.1029/2005GL025044.10.1029/2005GL025044

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2005GL025044%2Fpdf

refpaperuri:(2f8780cd5f4e2509688c715ee975c800)

http://onlinelibrary.wiley.com/doi/10.1029/2005GL025044/pdf[1] There is good evidence that higher global temperatures will promote a rise of greenhouse gas levels, implying a positive feedback which will increase the effect of anthropogenic emissions on global temperatures. However, the magnitude of this effect predicted by the available models remains highly uncertain, due to the accumulation of uncertainties in the processes thought to be involved. Here we present an alternative way of estimating the magnitude of the feedback effect based on reconstructed past changes. Linking this information with the mid-range Intergovernmental Panel on Climate Change estimation of the greenhouse gas effect on temperature we suggest that the feedback of global temperature on atmospheric CO 2 will promote warming by an extra 15鈥78% on a century-scale. This estimate may be conservative as we did not account for synergistic effects of likely temperature moderated increase in other greenhouse gases. Our semi-empirical approach independently supports process based simulations suggesting that feedback may cause a considerable boost in warming.

Schimel D., B. B. Stephens, and J. B. Fisher, 2014: Effect of increasing CO₂ on the terrestrial carbon cycle. Proc. Natl. Acad. Sci. U. S. A.,112, 436-441, doi: 10.1073/pnas.1407302112.6b556a6b-cab0-4ef3-be09-19e16a94d500

5e5f9c09f3b69674daff1e06c7ebfa7a

http%3A%2F%2Fnldr.library.ucar.edu%2Frepository%2Fcollections%2FOSGC-000-000-021-422

refpaperuri:(077429c198e5ffad961a7a2870c781b9)

http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-021-422Feedbacks from the terrestrial carbon cycle significantly affect future climate change. The CO60 concentration dependence of global terrestrial carbon storage is one of the largest and most uncertain feedbacks. Theory predicts the CO60 effect should have a tropical maximum, but a large terrestrial sink has been contradicted by analyses of atmospheric CO60 that do not show large tropical uptake. Our results, however, show significant tropical uptake and, combining tropical and extratropical fluxes, suggest that up to 60% of the present-day terrestrial sink is caused by increasing atmospheric CO60. This conclusion is consistent with a validated subset of atmospheric analyses, but uncertainty remains. Improved model diagnostics and new space-based observations can reduce the uncertainty of tropical and temperate zone carbon flux estimates. This analysis supports a significant feedback to future atmospheric CO60 concentrations from carbon uptake in terrestrial ecosystems caused by rising atmospheric CO60 concentrations. This feedback will have substantial tropical contributions, but the magnitude of future carbon uptake by tropical forests also depends on how they respond to climate change and requires their protection from deforestation.

Shaffer G., J. L. Sarmiento, 1995: Biogeochemical cycling in the global ocean: 1. A new, analytical model with continuous vertical resolution and high-latitude dynamics. J. Geophys. Res., 100, 2659- 2672.10.1029/94JC01167

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F94JC01167%2Fabstract

refpaperuri:(700299e2150a43335225458c0ab1b546)

http://onlinelibrary.wiley.com/doi/10.1029/94JC01167/abstractA new, simple analytical model of ocean chemistry is presented which includes continuous vertical resolution, high-latitude dynamics, air-sea exchange and sea ice cover. In this high-latitude exchange/interior diffusion-advection (HILDA) model, ocean physics are represented by four parameters: k and w , an eddy diffusion coefficient and a deep upwelling velocity in the stratified interior; q , a rate of lateral exchange between the interior and a well-mixed, deep polar ocean; and u, an exchange velocity between surface and deep layers in the polar ocean. First, estimates are made of ice-free and ice-covered areas at high latitudes, surface temperatures, and air-sea exchange velocities from available data. Then values of the physical parameters are estimated from simultaneous, least mean square fits of model solutions for temperature ( T ) and “abiotic” carbon 14 (Δ 14 C) to interior profiles of T and Δ 14 C and surface layer Δ 14 C values all derived from available data. Best fit values for k , w , q , and u are 3.2×10 615 m 2 s 611 , 2.0×10 618 m s 611 , 7.5×10 6111 s 611 and 1.9×10 616 m s 611 respectively. These results are interpreted in terms of modes of ocean circulation and mixing and compared with results from other simplier and more complex models. In parts 2 and 3 of this series, these values for k , w , q and u are taken as inputs for studying phosphorus, oxygen, and carbon cycling in the global ocean with the HILDA model.

Siegenthaler U., H. Oeschger, 1987: Biospheric CO₂ emissions during the past 200 years reconstructed by deconvolution of ice core data. Tellus B, 39, 140- 154.10.1111/j.1600-0889.1987.tb00278.x

87a2f7d4-1d15-47cd-b2cf-6d1688744fd4

02f28a7f2b583a6ce1590781137d59e2

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1111%2Fj.1600-0889.1987.tb00278.x%2Fabstract

refpaperuri:(7c417314b639d27c63e73ea319b5bd1c)

http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0889.1987.tb00278.x/abstractABSTRACT Measurements on air trapped in old polar ice have revealed that the pre-industrial atmosphere contained 280 ppm of CO 2 and that δ 13 C of atmospheric CO 2 decreased by about 1.1 %, until 1980. These measurements show that considerable amounts of non-fossil CO 2 must have already been emitted into the atmosphere in the 19th century. Quantitative estimates of the emission rates were performed by deconvolving the CO 2 and δ 13 C records, using models of the global carbon cycle (box-diffusion and outcrop-diffusion ocean, four-box biosphere). Depending on the structure of the ocean submodel, deconvolution of the CO 2 record yields a cumulative non-fossil production of about 90 to 150 Gt C until 1980, of which more than 50% were released prior to 1900. According to the model results, the net non-fossil production rate was roughly constant in the 19th and the first part of the 20th century. In the past 30 years, smaller values are obtained (0-0.9 Gt C yr 611 ) which are at the lower limit or below current ecological estimates for deforestation and land use (1.6 ± 0.8 Gt C yr 611 ). The difference might possibly be due to other sinks, e.g., stimulation of plant productivity by the enhanced CO 2 concentration. Calculated 13 C and 14 C time histories agree well with the observed changes. While the change of the atmospheric CO 2 concentration reflects more the cumulative carbon release, the isotope concentrations are more sensitive to short-term changes of the emission rate. The reason is that the oceanic uptake capacity is smaller for excess CO 2 by the buffer factor of 00 10 than for an isotopic perturbation.

Siegenthaler U., F. Joos, 1992: Use of a simple model for studying oceanic tracer distributions and the global carbon cycle. Tellus B, 44, 186- 207.10.1034/j.1600-0889.1992.t01-2-00003.x

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d205fdacbd6bd740f869913621e574fb

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1034%2Fj.1600-0889.1992.t01-2-00003.x%2Fabstract

refpaperuri:(812ee9520513407d8d6fa40dc2c5ad33)

http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0889.1992.t01-2-00003.x/abstractABSTRACT We have studied, based on work of Shaffer and Sarmiento (1992), a model for simulating the transport of CO 2 and tracers in the ocean (HILDA, for High-Latitude Exchange/Interior Diffusion-Advection Model) that combines features of box models and of the box-diffusion model. It is latitudinally divided into two zones; in the low latitudes, transport into the deep ocean occurs by eddy diffusion, while the high-latitude zone consists of two boxes (surface and deep ocean). We compare different ways of calibration and find that in order to reproduce the distributions of natural 14 C as well as of bomb-produced 14 C, the vertical eddy diffusivity K must decrease with depth. The concept of eddy diffusion is discussed by calculating apparent eddy diffusivities from 3-D model tracer simulations. The depth dependence of K is qualitatively confirmed by these calculations, reflecting the fact that the water circulation is more vigorous near the surface than at depth. We find that eddy diffusivities derived from 14 C are not appropriate for representing the large-scale vertical temperature distribution, because the latitudinal distribution of temperature differs in a systematic way from that of 14 C and also of anthropogenic CO 2 . Oceanic uptake of anthropogenic CO 2 , biospheric CO 2 emissions and isotopic perturbations are calculated, based on the observed atmospheric CO 2 concentration history. The results indicate an oceanic uptake of 1.9 Gt C yr 鈭1 in 1980 and a near-zero net contribution from the biota in the past several decades. The HILDA model is compared with other models, and we find that its response to atmospheric CO 2 perturbations is rather similar to that of a 3-D ocean carbon cycle model of Sarmiento etal. (1992).

Sigman D. M., E. A. Boyle, 2000: Glacial/interglacial variations in atmospheric carbon dioxide. Nature, 407, 859- 869.10.1038/35038000

11057657

98b81f8aaa369d7e795975a6978aa56e

http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM11057657

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM11057657Presents a hypothesis to explain why the carbon dioxide in the atmosphere during the ice ages was lower than it is in the present. Idea that the ocean's biological pump mechanism was more efficient during glacial times because of more complete utilization of algal nutrients at high altitudes, where much of the nutrient supply currently goes unused; Focus of the hypothesis on the open ocean surrounding Antarctica.

Sitch S., Coauthors, 2008: Evaluation of the terrestrial carbon cycle, future plant geography and climate-carbon cycle feedbacks using five Dynamic Global Vegetation Models (DGVMs). Global Change Biology, 14, 2015- 2039.10.1111/j.1365-2486.2008.01626.x

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849cba5ab63c4d68e28e1fba14797587

http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1111%2Fj.1365-2486.2008.01626.x%2Fcitedby

refpaperuri:(83194e7870f7f709aa91b757bb3fe3c8)

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2008.01626.x/citedbyThis study tests the ability of five Dynamic Global Vegetation Models (DGVMs), forced with observed climatology and atmospheric CO 2 , to model the contemporary global carbon cycle. The DGVMs are also coupled to a fast `climate analogue model', based on the Hadley Centre General Circulation Model (GCM), and run into the future for four Special Report Emission Scenarios (SRES): A1FI, A2, B1, B2. Results show that all DGVMs are consistent with the contemporary global land carbon budget. Under the more extreme projections of future environmental change, the responses of the DGVMs diverge markedly. In particular, large uncertainties are associated with the response of tropical vegetation to drought and boreal ecosystems to elevated temperatures and changing soil moisture status. The DGVMs show more divergence in their response to regional changes in climate than to increases in atmospheric CO 2 content. All models simulate a release of land carbon in response to climate, when physiological effects of elevated atmospheric CO 2 on plant production are not considered, implying a positive terrestrial climate-carbon cycle feedback. All DGVMs simulate a reduction in global net primary production (NPP) and a decrease in soil residence time in the tropics and extra-tropics in response to future climate. When both counteracting effects of climate and atmospheric CO 2 on ecosystem function are considered, all the DGVMs simulate cumulative net land carbon uptake over the 21st century for the four SRES emission scenarios. However, for the most extreme A1FI emissions scenario, three out of five DGVMs simulate an annual net source of CO 2 from the land to the atmosphere in the final decades of the 21st century. For this scenario, cumulative land uptake differs by 494鈥塒g鈥塁 among DGVMs over the 21st century. This uncertainty is equivalent to over 50 years of anthropogenic emissions at current levels.

Takahashi T., J. Olafsson, J. G. Goddard, D. W. Chipman, and S. C. Sutherland, 1993: Seasonal variation of CO₂ and nutrients in the high-latitude surface oceans: a comparative study. Global Biogeochemical Cycles, 7, 843- 878.10.1029/93GB02263

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F93GB02263%2Ffull

refpaperuri:(49254963322c560571a522fe6a8e923c)

http://onlinelibrary.wiley.com/doi/10.1029/93GB02263/fullSeasonal data for pCO 2 and the concentrations of CO 2 and nutrients in high-latitude surface oceans obtained by the Lamont-Doherty CO 2 group and Marine Research Institute, Reykjavik, are presented and analyzed. The seasonal progression and relationships between these properties are described, and their inter-ocean variation is compared. Spring phytoplankton blooms in the surface water of the North Atlantic Ocean and Iceland Sea caused a precipitous reduction of surface water pCO 2 and the concentrations of CO 2 and nutrients within two weeks, and proceeded until the nutrient salts were exhausted. This type of seasonal behavior is limited to the high-latitude (north of approximately 40°N) North Atlantic Ocean and adjoining seas. In contrast, seasonal changes in CO 2 and nutrients were more gradual in the North Pacific and the nutrients were only partially consumed in the surface waters of the subarctic North Pacific Ocean and Southern Ocean. The magnitude of seasonal changes in nutrient concentrations in the North Pacific and Southern Oceans was similar to that observed in the North Atlantic and adjoining seas. In the subpolar and polar waters of the North and South Atlantic and North Pacific Oceans, pCO 2 and the concentrations Of CO 2 and nutrients were much higher during winter than summer. During winter, the high latitude areas of the North Atlantic, North Pacific, and Weddell Sea were sources for atmospheric CO 2 ; during summer, they became CO 2 sinks. This is attributed to the upwelling of deep waters rich in CO 2 and nutrients during winter, and the intense photosynthesis occurring in strongly stratified upper layers during summer. On the other hand, subtropical waters were a CO 2 source in summer and a sink in winter. Since these waters were depleted of nutrients and could only sustain low levels of primary production, the seasonal variation of pCO 2 in subtropical waters and the CO 2 sink/source condition were governed primarily by temperature. An intense CO 2 sink zone was found along the confluence of the subtropical and subpolar waters (or the subtropical convergence). Its formation is attributed to the combined effects of cooling in subtropical waters and photosynthetic drawdown of CO 2 in subpolar waters.

Wang W.L., Coauthors, 2013: Variations in atmospheric CO₂ growth rates coupled with tropical temperature. Proc. Natl. Acad. Sci. U. S. A.,110, 13 061-13 066, doi: 10.1073/pnas. 1219683110.10.1073/pnas.1219683110

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http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM23884654

refpaperuri:(b81804cd8bf9229cb38b7c63b2395e64)

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM23884654Previous studies have highlighted the occurrence and intensity of El Ni09o-Southern Oscillation as important drivers of the interannual variability of the atmospheric CO2 growth rate, but the underlying biogeophysical mechanisms governing such connections remain unclear. Here we show a strong and persistent coupling (r(2) ≈ 0.50) between interannual variations of the CO2 growth rate and tropical land-surface air temperature during 1959 to 2011, with a 1 °C tropical temperature anomaly leading to a 3.5 ± 0.6 Petagrams of carbon per year (PgC/y) CO2 growth-rate anomaly on average. Analysis of simulation results from Dynamic Global Vegetation Models suggests that this temperature-CO2 coupling is contributed mainly by the additive responses of heterotrophic respiration (Rh) and net primary production (NPP) to temperature variations in tropical ecosystems. However, we find a weaker and less consistent (r(2) ≈ 0.25) interannual coupling between CO2 growth rate and tropical land precipitation than diagnosed from the Dynamic Global Vegetation Models, likely resulting from the subtractive responses of tropical Rh and NPP to precipitation anomalies that partly offset each other in the net ecosystem exchange (i.e., net ecosystem exchange ≈ Rh - NPP). Variations in other climate variables (e.g., large-scale cloudiness) and natural disturbances (e.g., volcanic eruptions) may induce transient reductions in the temperature-CO2 coupling, but the relationship is robust during the past 50 y and shows full recovery within a few years after any such major variability event. Therefore, it provides an important diagnostic tool for improved understanding of the contemporary and future global carbon cycle.

Welp L.R., Coauthors, 2011: Interannual variability in the oxygen isotopes of atmospheric CO₂ driven by El Nino. Nature, 477, 579- 582.10.1038/nature10421

21956330

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http%3A%2F%2Fmed.wanfangdata.com.cn%2FPaper%2FDetail%2FPeriodicalPaper_PM21956330

refpaperuri:(20fc33d979e221d85197649df009d9cc)

http://med.wanfangdata.com.cn/Paper/Detail/PeriodicalPaper_PM21956330The stable isotope ratios of atmospheric CO2 (18O/16O and 13C/12C) have been monitored since 1977 to improve our understanding of the global carbon cycle, because biosphere-atmosphere exchange fluxes affect the different atomic masses in a measurable way. Interpreting the 18O/16O variability has proved difficult, however, because oxygen isotopes in CO2 are influenced by both the carbon cycle and the water cycle. Previous attention focused on the decreasing 18O/16O ratio in the 1990s, observed by the global Cooperative Air Sampling Network of the US National Oceanic and Atmospheric Administration Earth System Research Laboratory. This decrease was attributed variously to a number of processes including an increase in Northern Hemisphere soil respiration; a global increase in C4 crops at the expense of C3 forests; and environmental conditions, such as atmospheric turbulence and solar radiation, that affect CO2 exchange between leaves and the atmosphere. Here we present 30 years' worth of data on 18O/16O in CO2 from the Scripps Institution of Oceanography global flask network and show that the interannual variability is strongly related to the El Ni17o/Southern Oscillation. We suggest that the redistribution of moisture and rainfall in the tropics during an El Ni17o increases the 18O/16O ratio of precipitation and plant water, and that this signal is then passed on to atmospheric CO2 by biosphere-atmosphere gas exchange. We show how the decay time of the El Ni17o anomaly in this data set can be useful in constraining global gross primary production. Our analysis shows a rapid recovery from El Ni17o events, implying a shorter cycling time of CO2 with respect to the terrestrial biosphere and oceans than previously estimated. Our analysis suggests that current estimates of global gross primary production, of 120 petagrams of carbon per year, may be too low, and that a best guess of 150-175 petagrams of carbon per year better reflects the observed rapid cycling of CO2. Although still tentative, such a revision would present a new benchmark by which to evaluate global biospheric carbon cycling models.

Wigley T. M. L., 1991: A simple inverse carbon cycle model. Global Biogeochemical Cycles, 5( 4), 373- 382.10.1029/91GB02279

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http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F91GB02279%2Fabstract

http://onlinelibrary.wiley.com/doi/10.1029/91GB02279/abstractThe convolution integral form of a carbon cycle model is transformed to a simple first-order differential equation. This allows one to derive an extremely efficient numerical algorithm for the carbon cycle model. The algorithm can be easily inverted to obtain a practical and efficient inverse carbon cycle model. The model is described and an example is given showing how modelled land-use-change emissions over 1765–1990 vary with assumptions made regarding the efficiency of oceanic CO 2 uptake.

Willeit M., A. Ganopolski, D. Dalmonech, A. M. Foley, and G. Feulner, 2014: Time-scale and state dependence of the carbon-cycle feedback to climate. Climate Dyn., 42, 1699- 1713.10.1007/s00382-014-2102-z

378fe9726a08afc322c51e147ae91ff9

http%3A%2F%2Fonlinelibrary.wiley.com%2Fresolve%2Freference%2FXREF%3Fid%3D10.1007%2Fs00382-014-2102-z

http://onlinelibrary.wiley.com/resolve/reference/XREF?id=10.1007/s00382-014-2102-zABSTRACT Climate and atmospheric CO2 concentration are intimately coupled in the Earth system: CO2 influences climate through the greenhouse effect, but climate also affects CO2 through its impact on the amount of carbon stored on land and in the ocean. The change in atmospheric CO2 as a response to a change in temperature (DCO2=DT) is a useful measure to quantify the feedback between the carbon cycle and climate. Using an ensemble of experiments with an Earth system model of intermediate complexity we show a pronounced time-scale dependence of DCO2=DT. A maximum is found on centennial scales with DCO2=DT values for the model ensemble in the range 5–12 ppm -1, while lower values are found on shorter and longer time scales. These results are consistent with estimates derived from past observations. Up to centennial scales, the land carbon response to climate dominates the CO2 signal in the atmosphere, while on longer time scales the ocean becomes important and eventually dominates on multi-millennial scales. In addition to the time-scale dependence, modeled DCO2=DT show a distinct dependence on the initial state of the system. In particular, on centennial time-scales, high DCO2=DT values are correlated with high initial land carbon content. A similar relation holds also for the CMIP5 models, although for DCO2=DT computed from a very different experimental setup. The emergence of common patterns like this could prove to usefully constrain the climate–carbon cycle feedback.

Woodwell G. M., F. T. Mackenzie, R. A. Houghton, M. Apps, E. Gorham, and E. Davidson, 1998: Biotic feedbacks in the warming of the Earth. Climatic Change, 40, 495- 518.10.1023/A:1005345429236

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http%3A%2F%2Fwww.springerlink.com%2Fcontent%2Ft01j106037201557%2F

http://www.springerlink.com/content/t01j106037201557/A positive correlation exists between temperature and atmospheric concentrations of carbon dioxide and methane over the last 220,000 years of glacial history, including two glacial and three interglacial periods. A similar correlation exists for the Little Ice Age and for contemporary data. Although the dominant processes responsible may be different over the three time periods, a warming trend, once established, appears to be consistently reinforced through the further accumulation of heat-trapping gases in the atmosphere; a cooling trend is reinforced by a reduction in the release of heat-trapping gases. Over relatively short periods of years to decades, the correspondence between temperature and greenhouse gas concentrations may be due largely to changes in the metabolism of terrestrial ecosystems, whose respiration, including microbial respiration in soils, responds more sensitively, and with a greater total effect, to changes in temperature than does gross photosynthesis. Despite the importance of positive feedbacks and the recent rise in surface temperatures, terrestrial ecosystems seem to have been accumulating carbon over the last decades. The mechanisms responsible are thought to include increased nitrogen mobilization as a result of human activities, and two negative feedbacks: CO 2 fertilization and the warming of the earth, itself, which is thought to lead to an accumulation of carbon on land through increased mineralization of nutrients and, as a result, increased plant growth. The relative importance of these mechanisms is unknown, but collectively they appear to have been more important over the last century than a positive feedback through warming-enhanced respiration. The recent rate of increase in temperature, however, leads to concern that we are entering a new phase in climate, one in which the enhanced greenhouse effect is emerging as the dominant influence on the temperature of the earth. Two observations support this concern. One is the negative correlation between temperature and global uptake of carbon by terrestrial ecosystems. The second is the positive correlation between temperature and the heat-trapping gas content of the atmosphere. While CO 2 fertilization or nitrogen mobilization (either directly or through a warming-enhanced mineralization) may partially counter the effects of a warming-enhanced respiration, the effect of temperature on the metabolism of terrestrial ecosystems suggests that these processes will not entirely compensate for emissions of carbon resulting directly from industrial and land-use practices and indirectly from the warming itself. The magnitude of the positive feedback, releasing additional CO 2 , CH 4 , and N 2 O, is potentially large enough to affect the rate of warming significantly.

Young P., 1999: Data-based mechanistic modelling, generalised sensitivity and dominant mode analysis. Computer Physics Communications, 117, 113- 129.10.1016/S0010-4655(98)00168-4

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http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0010465598001684

http://www.sciencedirect.com/science/article/pii/S0010465598001684Since the inherent uncertainty associated with most environmental and climatic systems is often acknowledged, it is surprising that most mathematical models of such systems are large, complex and completely deterministic in nature. In this situation, it seems sensible to consider alternative modelling methodologies which overtly acknowledge the often poorly defined nature of such systems and attempt to find simpler, stochastic descriptions which are more appropriate to the often limited data and information base. This paper considers one such approach,(DBM) modelling, and demonstrates how it can be useful not only for the modelling of environmental and other systems directly from time series data, but also as an approach to the evaluation and simplification of large deterministic simulation models. To achieve these objectives, the DBM approach exploits various methodological tools, including advanced methods of statistical identification and estimation; a particular form ofbased on; and, the latter involving a new statistical approach to combined model linearisation and order reduction. These various techniques are outlined in the paper and they are applied to the stochastic modelling of water pollution in rivers and the evaluation of nonlinear global carbon cycle models.