ORCID Profile
0000-0002-7796-6917
Current Organisations
CSIRO
,
La Trobe University
,
University of New South Wales
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Publisher: Springer Science and Business Media LLC
Date: 25-06-2013
DOI: 10.1038/NCLIMATE1925
Publisher: Cambridge University Press (CUP)
Date: 2013
Publisher: Springer Science and Business Media LLC
Date: 09-2011
DOI: 10.1038/NATURE10421
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 S ling 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.
Publisher: Springer Science and Business Media LLC
Date: 25-07-2016
DOI: 10.1038/NGEO2769
Publisher: IOP Publishing
Date: 16-05-2019
Publisher: Copernicus GmbH
Date: 18-07-2017
DOI: 10.5194/GMD-2017-166
Abstract: Abstract. The isotopic composition of carbon (Δ14C and δ13C) in atmospheric CO2 and in oceanic and terrestrial carbon reservoirs is influenced by anthropogenic emissions and by natural carbon exchanges, which can respond to and drive changes in climate. Simulations of 14C and 13C in the ocean and terrestrial components of Earth System Models (ESMs) present opportunities for model evaluation and for investigation of carbon cycling, including anthropogenic CO2 emissions and uptake. The use of carbon isotopes in novel evaluation of the ESMs' component ocean and terrestrial biosphere models and in new analyses of historical changes may improve predictions of future changes in the carbon cycle and climate system. We compile existing data to produce records of Δ14C and δ13C in atmospheric CO2 for the historical period 1850–2015. The primary motivation for this compilation is to provide the atmospheric boundary condition for historical simulations in the Coupled Model Intercomparison Project 6 (CMIP6) for models simulating carbon isotopes in their ocean or terrestrial biosphere models. The data may also be useful for other carbon cycle modelling activities.
Publisher: Elsevier BV
Date: 2011
Publisher: Wiley
Date: 18-02-2021
DOI: 10.1002/RCM.9014
Publisher: Copernicus GmbH
Date: 14-12-2018
Abstract: Abstract. Ice core records of the major atmospheric greenhouse gases (CO2, CH4, N2O) and their isotopologues covering recent centuries provide evidence of biogeochemical variations during the Late-Holocene and Pre-Industrial Periods and over the transition to the Industrial Period. These records come from a number of ice core and firn air sites, and have been measured in several laboratories around the world and show common features, but also unresolved differences. Here we present revised records, including new measurements, performed at the CSIRO Ice Core Extraction LABoratory (ICELAB) on air s les from ice obtained at the high accumulation site of Law Dome (East Antarctica). We are motivated by the increasing use of the records by the scientific community and by recent data-handling developments at CSIRO-ICELAB. A number of cores and firn air s les have been collected at Law Dome to provide high resolution records overlapping recent, direct atmospheric observations. The records have been updated through a dynamic link to the calibration scales used in the Global Atmospheric S ling LABoratory (GASLAB) at CSIRO, which are periodically revised with information from the latest calibration experiments. The gas-age scales have been revised based on new ice-age scales, and the information derived from a new version of the CSIRO firn diffusion model. Additionally, the records have been revised with new, rule-based selection criteria and updated corrections for biases associated with the extraction procedure, and the effects of gravity and diffusion in the firn. All measurements carried out in ICELAB-GASLAB over the last 25 years are now managed through a database (the ICElab dataBASE or ICEBASE) which provides consistent data management, automatic corrections and selection of measurements, and a web-based user interface for data extraction. We present the new records, discuss their strengths and limitations and summarise their main features. The records reveal changes in the carbon cycle and atmospheric chemistry over the last two millennia, including the major changes of the anthropogenic era and the smaller, mainly natural variations beforehand. They provide the historical data to calibrate and test the next inter-comparison of models used to predict future climate change (Coupled Model Inter-comparison Project - phase 6, CMIP6). The datasets described in this paper, including spline fits, are available at 0.25919/5bfe29ff807fb (Rubino et al., 2018).
Publisher: Wiley
Date: 24-02-2021
DOI: 10.1002/RCM.9018
Abstract: In recent years, the primary reference material (RM) for the VPDB scale, NBS19, has become unavailable, and the RM used for low‐end scale‐anchoring, LSVEC, was found unsuitable due a drift in the δ 13 C value. Given these problems, new RMs aimed at realising the VPDB δ 13 C scale with low uncertainty were produced. Establishing the consistency of the new RMs with the “old” RMs prompted our revision of the underlying principles of RM value assignments, and the VPDB δ 13 C scale realisation and its long‐term sustainability. Analysis of major developments of the VPDB scale, a review of the contemporary requirements for RMs, and comparison with well‐established measurement scales have been performed, with the aim of revising the VPDB δ 13 C scale, principles of RM value assignments, and calibrator hierarchy. Requirements for scale‐anchoring RMs with low uncertainty and measures to establish the scale sustainability have been formulated. The revised scale realisation is based on multiple reference points, well‐defined calibration hierarchy and the use of well‐understood methods for value assignment. The realisation scheme includes the new primary RM IAEA‐603 and scale‐anchoring RMs IAEA‐610, IAEA‐611 and IAEA‐612, covering δ 13 C from +2.46 to −36.7 ‰ VPDB, with uncertainties, including inhomogeneity and stability assessment, of less than 0.015 ‰. The values of these four RMs were assigned in a mutually consistent way agreement between measurements made using this realisation with those made using the VPDB scale of 2006 has been demonstrated on NIST CO 2 RMs 8562–8564. Multipoint‐anchoring of the VPDB δ 13 C scale provides several distinct “points” on the scale as means for cross‐measurements to check the stability and viability of RMs and detect drift of values, if any. This ensures that the δ 13 C scale is suitable for the most demanding applications, and provides options for developing further RMs with high accuracy inside a robust scale realisation scheme.
Publisher: Copernicus GmbH
Date: 18-07-2017
Publisher: American Geophysical Union (AGU)
Date: 15-08-2013
DOI: 10.1002/JGRD.50668
Publisher: Copernicus GmbH
Date: 11-02-2015
Abstract: Abstract. We analyse global and regional changes in CO2 fluxes using two simple models, an airborne fraction of anthropogenic emissions and a linear relationship with CO2 concentrations. We show that both models are able to fit the non-anthropogenic (hereafter natural) flux over the length of the atmospheric concentration record. Analysis of the linear model (including its uncertainties) suggests no significant decrease in the response of the natural carbon cycle. Recent data points rather to an increase. We apply the same linear diagnostic to fluxes from atmospheric inversions. Flux responses show clear regional and seasonal patterns driven by terrestrial uptake in the northern summer. Ocean fluxes show little or no linear response. Terrestrial models show clear responses, agreeing globally with the inversion responses, however the spatial structure is quite different, with dominant responses in the tropics rather than the northern extratropics.
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/EN19322
Abstract: Environmental contextChlorofluorocarbons (CFCs) are potent greenhouse and stratospheric ozone depleting trace gases. Their atmospheric concentrations are in decline, thanks to global production and consumption controls imposed by the Montreal Protocol. In recent years, the rates of decline of CFC atmospheric concentrations, especially for CFC-11 (CCl3F), are not as large as anticipated under the Protocol, resulting in renewed efforts to estimate CFC consumption and/or emissions to possibly identify new or poorly quantified sources. AbstractAustralian emissions of chlorofluorocarbons (CFCs) have been estimated from atmospheric CFC observations by both inverse modelling and interspecies correlation techniques, and from CFC production, import and consumption data compiled by industry and government. Australian and global CFC emissions show similar temporal behaviour, with emissions peaking in the late-1980s and then declining by ~10% per year through to the present. Australian CFC emissions since 1978 account for less than 1% of global emissions and therefore make a correspondingly small contribution to stratospheric ozone depletion. The current CFC emissions in Australia are likely from ‘banks’ of closed-cell foams, and refrigeration–air conditioning equipment now more than 20 years old. There is no evidence of renewed consumption or emissions of CFCs in Australia. The reduction in CFC emissions has made a significant contribution to reducing Australian greenhouse gas emissions.
Publisher: Copernicus GmbH
Date: 25-06-2014
Abstract: Abstract. We analyze 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 nonanthropogenic (hereafter natural) flux over the length of the atmospheric concentration record and that departures in the airborne fraction model are largely due to departures from exponential growth of emissions. Analysis of the first-order model (including its uncertainties) suggests no significant change in the response of the natural carbon cycle. We apply the same first-order diagnostic to fluxes from atmospheric inversions. Their responses show clear regional and seasonal patterns driven by terrestrial uptake in the northern summer. Ocean fluxes show little or no first-order response. terrestrial models also 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.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/EN13171
Abstract: Environmental context Carbon tetrachloride in the background atmosphere is a significant environmental concern, responsible for ~10% of observed stratospheric ozone depletion. Atmospheric concentrations of CCl4 are higher than expected from currently identified emission sources: largely residual emissions from production, transport and use. Additional sources are required to balance the expected atmospheric destruction of CCl4 and may contribute to a slower-than-expected recovery of the Antarctic ozone ‘hole’. Abstract Global (1978–2012) and Australian (1996–2011) carbon tetrachloride emissions are estimated from atmospheric observations of CCl4 using data from the Advanced Global Atmospheric Gases Experiment (AGAGE) global network, in particular from Cape Grim, Tasmania. Global and Australian emissions are in decline in response to Montreal Protocol restrictions on CCl4 production and consumption for dispersive uses in the developed and developing world. However, atmospheric data-derived emissions are significantly larger than ‘bottom-up’ estimates from direct and indirect CCl4 production, CCl4 transportation and use. Australian CCl4 emissions are not a result of these sources, and the identification of the origin of Australian emissions may provide a clue to the origin of some of these ‘missing’ global sources.
Publisher: Copernicus GmbH
Date: 08-06-2023
DOI: 10.5194/AMT-2023-99
Abstract: Abstract. Since 1999, Environment and Climate Change Canada (ECCC) has been coordinating a multi-laboratory comparison of measurements of long-lived greenhouse gases in whole air s les collected at the Global Atmosphere Watch (GAW) Alert Observatory located in the Canadian high Arctic (82°28' N, 62°30' W). In this paper, we evaluate the measurement agreement of atmospheric CO2, CH4, N2O, SF6, and stable isotopes of CO2 (δ13C, δ18O) between leading laboratories from 7 independent international institutions. The measure of success is linked to target goals for network compatibility outlined by the World Meteorological Organization’s (WMO) GAW greenhouse gas measurement community. Overall, based on ~8000 discrete flask s les, we find that the co-located atmospheric CO2 and CH4 measurement records from Alert by CSIRO, MPI-BGC, SIO, UHEI-IUP, ECCC, and NOAA are generally consistent with the WMO compatibility goals of ±0.1 ppm CO2 and ±2 ppb CH4 over the 17-year period (1999 – 2016), although there are periods where differences exceed target levels and persist as systematic bias for months or years. Consistency with the WMO goals for N2O, SF6, and stable isotopes of CO2 (δ13C, δ18O) has not been demonstrated. Additional analysis of co-located comparison measurements between CSIRO, SIO, and NOAA at other geographical sites suggests that the findings at Alert for CO2, CH4, N2O and δ13C-CO2 could be extended across the CSIRO, SIO, and NOAA observing networks. Two approaches are carried out to determine the level of agreement as a collective for the 7 in idual laboratories (1) pooling the differences of in idual laboratories over the entire s ling records from a designated reference laboratory and determining the 95th percentile range of these data points and (2) averaging the 2 standard deviations (2-sigma) of the means for all flask s les taken in each in idual s ling episode over the entire s ling record. For CO2, from 5691 s les, we derive a measurement agreement level of -0.51 to +0.53 ppm using the 95th percentile range of the differences from NOAA measurements. Similarly, we derive a corresponding value of ± 0.37 ppm using the mean of 2-sigma values from 923 in idual weekly s ling episodes. For CO2 isotopes using INSTAAR measurements as a reference, we derive measurement agreement values of -0.09 to +0.07 and ± 0.06 ‰ for δ13C and -0.50 to +0.58 and ± 0.31 ‰ for δ18O, for the 95th percentile ranges and the mean of the 2-sigma values, respectively. For other gases, the corresponding values for both approaches are 4.86 to +6.16 and ± 3.62 ppb for CH4, -0.75 to +1.20 and ± 0.64 ppb for N2O, and -0.14 to +0.09 and ± 0.09 ppt for SF6. These upper and lower limits represent our best estimate of the measurement agreement at the 95 % confidence level for these in idual laboratories, providing more confidence for using these datasets in various scientific applications (e.g., long-term trend analysis).
Publisher: Copernicus GmbH
Date: 14-12-2018
Publisher: Copernicus GmbH
Date: 08-06-2023
Publisher: Copernicus GmbH
Date: 05-12-2017
Abstract: Abstract. The isotopic composition of carbon (Δ14C and δ13C) in atmospheric CO2 and in oceanic and terrestrial carbon reservoirs is influenced by anthropogenic emissions and by natural carbon exchanges, which can respond to and drive changes in climate. Simulations of 14C and 13C in the ocean and terrestrial components of Earth system models (ESMs) present opportunities for model evaluation and for investigation of carbon cycling, including anthropogenic CO2 emissions and uptake. The use of carbon isotopes in novel evaluation of the ESMs' component ocean and terrestrial biosphere models and in new analyses of historical changes may improve predictions of future changes in the carbon cycle and climate system. We compile existing data to produce records of Δ14C and δ13C in atmospheric CO2 for the historical period 1850–2015. The primary motivation for this compilation is to provide the atmospheric boundary condition for historical simulations in the Coupled Model Intercomparison Project 6 (CMIP6) for models simulating carbon isotopes in the ocean or terrestrial biosphere. The data may also be useful for other carbon cycle modelling activities.
Publisher: Springer Science and Business Media LLC
Date: 10-02-2013
DOI: 10.1038/NCLIMATE1817
Publisher: Copernicus GmbH
Date: 11-04-2019
Abstract: Abstract. Ice core records of the major atmospheric greenhouse gases (CO2, CH4, N2O) and their isotopologues covering recent centuries provide evidence of biogeochemical variations during the Late Holocene and pre-industrial periods and over the transition to the industrial period. These records come from a number of ice core and firn air sites and have been measured in several laboratories around the world and show common features but also unresolved differences. Here we present revised records, including new measurements, performed at the CSIRO Ice Core Extraction LABoratory (ICELAB) on air s les from ice obtained at the high-accumulation site of Law Dome (East Antarctica). We are motivated by the increasing use of the records by the scientific community and by recent data-handling developments at CSIRO ICELAB. A number of cores and firn air s les have been collected at Law Dome to provide high-resolution records overlapping recent, direct atmospheric observations. The records have been updated through a dynamic link to the calibration scales used in the Global Atmospheric S ling LABoratory (GASLAB) at CSIRO, which are periodically revised with information from the latest calibration experiments. The gas-age scales have been revised based on new ice-age scales and the information derived from a new version of the CSIRO firn diffusion model. Additionally, the records have been revised with new, rule-based selection criteria and updated corrections for biases associated with the extraction procedure and the effects of gravity and diffusion in the firn. All measurements carried out in ICELAB–GASLAB over the last 25 years are now managed through a database (the ICElab dataBASE or ICEBASE), which provides consistent data management, automatic corrections and selection of measurements, and a web-based user interface for data extraction. We present the new records, discuss their strengths and limitations, and summarise their main features. The records reveal changes in the carbon cycle and atmospheric chemistry over the last 2 millennia, including the major changes of the anthropogenic era and the smaller, mainly natural variations beforehand. They provide the historical data to calibrate and test the next inter-comparison of models used to predict future climate change (Coupled Model Inter-comparison Project – phase 6, CMIP6). The datasets described in this paper, including spline fits, are available at 0.25919/5bfe29ff807fb (Rubino et al., 2019).
Location: Australia
No related grants have been discovered for Colin Allison.