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4. Atmospheric evidence for a global secular increase in carbon isotopic discrimination of land photosynthesis

Author

Stephen C. Piper, Harro A. J. Meijer, Ralph F. Keeling, Jian Bi, Lisa R. Welp, Ying Sun, Heather Graven, A. F. Bollenbacher, Laure Resplandy, and Isotope Research

Subjects
0106 biological sciences, Fossil Fuels, 010504 meteorology & atmospheric sciences, IMPACT, Atmospheric sciences, 01 natural sciences, chemistry.chemical_compound, Ice core, MILLENNIUM, Photosynthesis, carbon-13 Suess effect, Carbon Isotopes, Multidisciplinary, Plants, Multidisciplinary Sciences, Isotopes of carbon, Climatology, Physical Sciences, Carbon dioxide, Science & Technology - Other Topics, CO2, SENSITIVITY, WATER-USE EFFICIENCY, DIOXIDE, Stomatal conductance, water use efficiency, Life on Land, Climate Change, STOMATAL CONDUCTANCE, Climate change, Carbon cycle, Carbon Cycle, Suess effect, DELTA-C-13, RATIO, OCEAN, CYCLE, isotope, 0105 earth and related environmental sciences, photosynthesis, Science & Technology, Atmosphere, Water, 15. Life on land, Carbon Dioxide, TRENDS, CLIMATE, chemistry, 13. Climate action, Environmental science, 010606 plant biology & botany
Abstract

A decrease in the C-13/C-12 ratio of atmospheric CO2 has been documented by direct observations since 1978 and from ice core measurements since the industrial revolution. This decrease, known as the C-13-Suess effect, is driven primarily by the input of fossil fuel-derived CO2 but is also sensitive to land and ocean carbon cycling and uptake. Using updated records, we show that no plausible combination of sources and sinks of CO2 from fossil fuel, land, and oceans can explain the observed C-13-Suess effect unless an increase has occurred in the C-13/C-12 isotopic discrimination of land photosynthesis. A trend toward greater discrimination under higher CO2 levels is broadly consistent with tree ring studies over the past century, with field and chamber experiments, and with geological records of C-3 plants at times of altered atmospheric CO2, but increasing discrimination has not previously been included in studies of long-term atmospheric 13C/12C measurements. We further show that the inferred discrimination increase of 0.014 +/- 0.007% ppm(-1) is largely explained by photorespiratory and mesophyll effects. This result implies that, at the global scale, land plants have regulated their stomatal conductance so as to allow the CO2 partial pressure within stomatal cavities and their intrinsic water use efficiency to increase in nearly constant proportion to the rise in atmospheric CO2 concentration.

Published
2017

5. Interannual variability in the oxygen isotopes of atmospheric CO2 driven by El Nino

Author

Lisa R. Welp, C. E. Allison, Harro A. J. Meijer, Kei Yoshimura, Martin Wahlen, Ralph F. Keeling, Roger J. Francey, Stephen C. Piper, A. F. Bollenbacher, and Isotope Research

Subjects
Crops, Agricultural, FLUXES, δ18O, Rain, Oxygen Isotopes, Atmospheric sciences, Latitude, Carbon Cycle, Trees, chemistry.chemical_compound, Soil, CARBON-DIOXIDE, O-18, Precipitation, Water cycle, DELTA-O-18, El Nino-Southern Oscillation, Carbon dioxide in Earth's atmosphere, Multidisciplinary, Atmosphere, Primary production, Water, Humidity, Carbon Dioxide, TERRESTRIAL GROSS, CLIMATE, MODEL, Oceanography, chemistry, Atmospheric chemistry, PRECIPITATION, Carbon dioxide, PATTERNS, Environmental science, VEGETATION
Abstract

The stable isotope ratios of atmospheric CO(2) ((18)O/(16)O and (13)C/(12)C) 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 (18)O/(16)O variability has proved difficult, however, because oxygen isotopes in CO(2) are influenced by both the carbon cycle and the water cycle. Previous attention focused on the decreasing (18)O/(16)O 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 C(4) crops at the expense of C(3) forests; and environmental conditions, such as atmospheric turbulence and solar radiation, that affect CO(2) exchange between leaves and the atmosphere. Here we present 30 years' worth of data on (18)O/(16)O in CO(2) from the Scripps Institution of Oceanography global flask network and show that the interannual variability is strongly related to the El Niño/Southern Oscillation. We suggest that the redistribution of moisture and rainfall in the tropics during an El Niño increases the (18)O/(16)O ratio of precipitation and plant water, and that this signal is then passed on to atmospheric CO(2) by biosphere-atmosphere gas exchange. We show how the decay time of the El Niño anomaly in this data set can be useful in constraining global gross primary production. Our analysis shows a rapid recovery from El Niño events, implying a shorter cycling time of CO(2) 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 CO(2). Although still tentative, such a revision would present a new benchmark by which to evaluate global biospheric carbon cycling models.

Published
2011

6. Atmospheric CO2 and 13CO2 Exchange with the Terrestrial Biosphere and Oceans from 1978 to 2000: Observations and Carbon Cycle Implications

Author

Stephen C. Piper, Timothy P. Whorf, Charles D. Keeling, Martin Heimann, Martin Wahlen, Harro A. J. Meijer, Robert B. Bacastow, and Isotope Research

Subjects
El Niño Southern Oscillation, Climatology, Atmospheric carbon cycle, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Biosphere, Environmental science, Atmospheric sciences, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), Carbon cycle
Published
2005

7. Two decades of ocean CO2 sink and variability

Author

Haroon S. Kheshgi, Philippe Bousquet, Philippe Ciais, Charles D. Keeling, Laurent Bopp, Olivier Aumont, Peter Rayner, Roger J. Francey, C. Le Quéré, Stephen C. Piper, Iain Colin Prentice, P. Peylin, Ralph F. Keeling, Martin Heimann, Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Laboratoire d'océanographie dynamique et de climatologie (LODYC), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Biogéochimie et écologie des milieux continentaux (Bioemco), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Paris (ENS Paris), Max-Planck-Institut für Biogeochemie (MPI-BGC), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), CSIRO Marine and Atmospheric Research [Aspendale], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California, ExxonMobil Upstream Research Company, ExxonMobil, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris ), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Scripps Institution of Oceanography (SIO - UC San Diego), University of California (UC)-University of California (UC), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut d'écologie et des sciences de l'environnement de Paris (iEES), and Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, PUITS, INVENTORY, O$_2$, BUDGET, 01 natural sciences, CLIMATOLOGIE, Sink (geography), CYCLE BIOGEOCHIMIQUE, chemistry.chemical_compound, DELTA-C-13, ATMOSPHERIC CARBON-DIOXIDE, INTERACTION OCEAN ATMOSPHERE, CYCLE, 0105 earth and related environmental sciences, Carbon dioxide in Earth's atmosphere, geography, geography.geographical_feature_category, ANTHROPOGENIC CO$_2$, 010604 marine biology & hydrobiology, VARIABILITE, Mean value, RISE, MODELISATION, Fossil fuel emissions, ANTHROPOGENIC CO2, O-2, MODEL, chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], Climatology, Carbon dioxide, Environmental science, GAZ CARBONIQUE
Abstract

International audience; Atmospheric CO2 has increased at a nearly identical average rate of 3.3 and 3.2 Pg C yr-1 for the decades of the 1980s and the 1990s, in spite of a large increase in fossil fuel emissions from 5.4 to 6.3 Pg C yr-1 Thus, the sum of the ocean and land CO2 sinks was 1 Pg C yr-1 larger in the 1990s than in to the 1980s. Here we quantify the ocean and land sinks for these two decades using recent atmospheric inversions and ocean models. The ocean and land sinks are estimated to be, respectively, 0.3 (0.1 to 0.6) and 0.7 (0.4 to 0.9) Pg C yr-1larger in the 1990s than in the 1980s. When variability less than 5 yr is removed, all estimates show a global oceanic sink more or less steadily increasing with time, and a large anomaly in the land sink during 1990-1994. For year-to-year variability, all estimates show 1/3 to 1/2 less variability in the ocean than on land, but the amplitude and phase of the oceanic variability remain poorly determined. A mean oceanic sink of 1.9 Pg C yr-1 for the 1990s based on O2 observations corrected for ocean outgassing is supported by these estimates, but an uncertainty on the mean value of the order of +/-0.7 Pg C yr-1 remains. The difference between the two decades appears to be more robust than the absolute value of either of the two decades.

Published
2003

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