ORCID Profile
0000-0002-7533-4430
Current Organisations
Charles Darwin University
,
Cardiff University
,
Centre for Australian Studies, University of Cologne
,
Batchelor Institute of Indigenous Tertiary Education
,
University of Cambridge
,
University of Oxford
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Publisher: Copernicus GmbH
Date: 23-02-2017
Abstract: Abstract. Past warm periods provide an opportunity to evaluate climate models under extreme forcing scenarios, in particular high ( 800 ppmv) atmospheric CO2 concentrations. Although a post hoc intercomparison of Eocene ( ∼ 50 Ma) climate model simulations and geological data has been carried out previously, models of past high-CO2 periods have never been evaluated in a consistent framework. Here, we present an experimental design for climate model simulations of three warm periods within the early Eocene and the latest Paleocene (the EECO, PETM, and pre-PETM). Together with the CMIP6 pre-industrial control and abrupt 4 × CO2 simulations, and additional sensitivity studies, these form the first phase of DeepMIP – the Deep-time Model Intercomparison Project, itself a group within the wider Paleoclimate Modelling Intercomparison Project (PMIP). The experimental design specifies and provides guidance on boundary conditions associated with palaeogeography, greenhouse gases, astronomical configuration, solar constant, land surface processes, and aerosols. Initial conditions, simulation length, and output variables are also specified. Finally, we explain how the geological data sets, which will be used to evaluate the simulations, will be developed.
Publisher: Unpublished
Date: 2015
Publisher: Elsevier BV
Date: 07-2022
Publisher: American Geophysical Union (AGU)
Date: 05-2021
DOI: 10.1029/2020PA004054
Abstract: The Miocene epoch, spanning 23.03–5.33 Ma, was a dynamic climate of sustained, polar lified warmth. Miocene atmospheric CO 2 concentrations are typically reconstructed between 300 and 600 ppm and were potentially higher during the Miocene Climatic Optimum (16.75–14.5 Ma). With surface temperature reconstructions pointing to substantial midlatitude and polar warmth, it is unclear what processes maintained the much weaker‐than‐modern equator‐to‐pole temperature difference. Here, we synthesize several Miocene climate modeling efforts together with available terrestrial and ocean surface temperature reconstructions. We evaluate the range of model‐data agreement, highlight robust mechanisms operating across Miocene modeling efforts and regions where differences across experiments result in a large spread in warming responses. Prescribed CO 2 is the primary factor controlling global warming across the ensemble. On average, elements other than CO 2 , such as Miocene paleogeography and ice sheets, raise global mean temperature by ∼2°C, with the spread in warming under a given CO 2 concentration (due to a combination of the spread in imposed boundary conditions and climate feedback strengths) equivalent to ∼1.2 times a CO 2 doubling. This study uses an ensemble of opportunity: models, boundary conditions, and reference data sets represent the state‐of‐art for the Miocene, but are inhomogeneous and not ideal for a formal intermodel comparison effort. Acknowledging this caveat, this study is nevertheless the first Miocene multi‐model, multi‐proxy comparison attempted so far. This study serves to take stock of the current progress toward simulating Miocene warmth while isolating remaining challenges that may be well served by community‐led efforts to coordinate modeling and data activities within a common analytical framework.
Publisher: American Geophysical Union (AGU)
Date: 03-2021
DOI: 10.1029/2020PA004165
Abstract: The mid‐to‐late Miocene is proposed as a key interval in the transition of the Earth's climate state toward that of the modern‐day. However, it remains a poorly understood interval in the evolution of Cenozoic climate, and the sparse proxy‐based climate reconstructions are associated with large uncertainties. In particular, tropical sea surface temperature (SST) estimates largely rely on the unsaturated alkenone U k 37 proxy, which fails to record temperatures higher than 29˚C, the TEX 86 proxy which has challenges around its calibration, and Mg/Ca ratios of poorly preserved foraminifera. We reconstruct robust, absolute, SSTs between 13.5 Ma and 9.5 Ma from the South West Indian Ocean (paleolatitude ∼5.5˚S) using laser‐ablation inductively coupled‐plasma mass spectrometer microanalysis of glassy planktic foraminiferal Mg/Ca. Employing this microanalytical technique, and stringent screening criteria, permits the reconstruction of paleotemperatures using foraminifera which although glassy, are contaminated by authigenic coatings. Our absolute estimates of 24–31°C suggest that SST in the tropical Indian Ocean was relatively constant between 13.5 and 9.5 Ma, similar to those reconstructed from the tropics using the U k 37 alkenone proxy. This finding suggests an interval of enhanced polar lification between 10 and 7.5 Ma, immediately prior to the global late Miocene Cooling.
Publisher: American Geophysical Union (AGU)
Date: 27-11-2020
DOI: 10.1029/2020PA003920
Publisher: Cambridge University Press (CUP)
Date: 16-09-2015
DOI: 10.1017/JIE.2015.24
Abstract: The role of artistry in transformative maintenance of law and custom is a theme widely researched and discussed in Aboriginal arts related literature. However, it is the aim of this paper to contribute to a wider discourse about learning and economic participation in remote Australia, and in particular the role of multimodality as a significant asset. The paper draws from relevant literature and two case studies one from Keringke Arts, and one from Eastern Arrernte teacher and artist, Kathleen Kemarre Wallace. In customary form, multimodality combines and recombines various modalities — including dance, song, sand drawing, body painting and design, storytelling, stories, rhythm, petroglyph and ochre-painted rock art — enabling the intergenerational teaching and learning of rich cultural heritage in ways which connect that experience to the law and custom of the homelands. Multimodality, as it is used in this paper, draws on the concept of ‘form-relationality’ the way various modalities are combined and recombined, as elements which together describe a body of knowledge and yet separately provide myriad detail. Although beyond the scope of this paper, multimodality is also a mediating influence between contemporary and customary elements and contexts. This paper considers the complexity of multimodality as an asset in a contemporary arts market.
Publisher: Copernicus GmbH
Date: 15-01-2021
Abstract: Abstract. We present results from an ensemble of eight climate models, each of which has carried out simulations of the early Eocene climate optimum (EECO, ∼ 50 million years ago). These simulations have been carried out in the framework of the Deep-Time Model Intercomparison Project (DeepMIP www.deepmip.org, last access: 10 January 2021) thus, all models have been configured with the same paleogeographic and vegetation boundary conditions. The results indicate that these non-CO2 boundary conditions contribute between 3 and 5 ∘C to Eocene warmth. Compared with results from previous studies, the DeepMIP simulations generally show a reduced spread of the global mean surface temperature response across the ensemble for a given atmospheric CO2 concentration as well as an increased climate sensitivity on average. An energy balance analysis of the model ensemble indicates that global mean warming in the Eocene compared with the preindustrial period mostly arises from decreases in emissivity due to the elevated CO2 concentration (and associated water vapour and long-wave cloud feedbacks), whereas the reduction in the Eocene in terms of the meridional temperature gradient is primarily due to emissivity and albedo changes owing to the non-CO2 boundary conditions (i.e. the removal of the Antarctic ice sheet and changes in vegetation). Three of the models (the Community Earth System Model, CESM the Geophysical Fluid Dynamics Laboratory, GFDL, model and the Norwegian Earth System Model, NorESM) show results that are consistent with the proxies in terms of the global mean temperature, meridional SST gradient, and CO2, without prescribing changes to model parameters. In addition, many of the models agree well with the first-order spatial patterns in the SST proxies. However, at a more regional scale, the models lack skill. In particular, the modelled anomalies are substantially lower than those indicated by the proxies in the southwest Pacific here, modelled continental surface air temperature anomalies are more consistent with surface air temperature proxies, implying a possible inconsistency between marine and terrestrial temperatures in either the proxies or models in this region. Our aim is that the documentation of the large-scale features and model–data comparison presented herein will pave the way to further studies that explore aspects of the model simulations in more detail, for ex le the ocean circulation, hydrological cycle, and modes of variability, and encourage sensitivity studies to aspects such as paleogeography, orbital configuration, and aerosols.
Publisher: American Geophysical Union (AGU)
Date: 03-2019
DOI: 10.1029/2018PA003420
Publisher: Copernicus GmbH
Date: 28-01-2021
Abstract: Abstract. The Eocene–Oligocene transition (EOT) was a climate shift from a largely ice-free greenhouse world to an icehouse climate, involving the first major glaciation of Antarctica and global cooling occurring ∼34 million years ago (Ma) and lasting ∼790 kyr. The change is marked by a global shift in deep-sea δ18O representing a combination of deep-ocean cooling and growth in land ice volume. At the same time, multiple independent proxies for ocean temperature indicate sea surface cooling, and major changes in global fauna and flora record a shift toward more cold-climate-adapted species. The two principal suggested explanations of this transition are a decline in atmospheric CO2 and changes to ocean gateways, while orbital forcing likely influenced the precise timing of the glaciation. Here we review and synthesise proxy evidence of palaeogeography, temperature, ice sheets, ocean circulation and CO2 change from the marine and terrestrial realms. Furthermore, we quantitatively compare proxy records of change to an ensemble of climate model simulations of temperature change across the EOT. The simulations compare three forcing mechanisms across the EOT: CO2 decrease, palaeogeographic changes and ice sheet growth. Our model ensemble results demonstrate the need for a global cooling mechanism beyond the imposition of an ice sheet or palaeogeographic changes. We find that CO2 forcing involving a large decrease in CO2 of ca. 40 % (∼325 ppm drop) provides the best fit to the available proxy evidence, with ice sheet and palaeogeographic changes playing a secondary role. While this large decrease is consistent with some CO2 proxy records (the extreme endmember of decrease), the positive feedback mechanisms on ice growth are so strong that a modest CO2 decrease beyond a critical threshold for ice sheet initiation is well capable of triggering rapid ice sheet growth. Thus, the litude of CO2 decrease signalled by our data–model comparison should be considered an upper estimate and perhaps artificially large, not least because the current generation of climate models do not include dynamic ice sheets and in some cases may be under-sensitive to CO2 forcing. The model ensemble also cannot exclude the possibility that palaeogeographic changes could have triggered a reduction in CO2.
Publisher: Wiley
Date: 09-02-2021
Publisher: Informa UK Limited
Date: 03-08-2022
DOI: 10.1080/10810730.2022.2134523
Abstract: Effective communication is critical for engagement between clients and health professionals, transfer of health information and health decision-making. Internationally, there is recognition that if health communication interventions were successfully implemented, then health communication equity would improve. This rapid realist review was undertaken with the aim of providing guidance on the circumstances in which communication interventions were likely to work in regional health service settings accessed by First Nations people from remote and very remote geographic areas of Australia. The realist review involved a process of searching literature on key terms and the identification of relevant studies and policies by a content expert group, including non-Indigenous and First Nations health researchers. Evidence was extracted to inform and synthesize into guiding principles, using a realist perspective. This review identified studies that provided evidence from 37 Australian and international settings where the dominant language and culture of the health sector differs from that of the majority of service users. A number of guiding principles were synthesized: 1) to build trust and respect by inclusion of an in idual patient's cultural perspective 2) to enhance concordant understanding of health information through two-way health literacies and learning 3) to recognize the entanglement of health communication equity with regional socio-cultural and health determinants. This review generated realist informed guiding principles to suggest how and under what conditions health communication interventions can enable healthcare decision-making at an in idual and service level.
Publisher: Elsevier
Date: 2008
Publisher: Edward Elgar Publishing
Date: 30-09-2016
Publisher: Wiley
Date: 18-01-2021
Publisher: Wiley
Date: 10-04-2020
Publisher: Copernicus GmbH
Date: 18-05-2020
Publisher: Informa UK Limited
Date: 23-12-2019
Publisher: Copernicus GmbH
Date: 18-05-2020
DOI: 10.5194/CP-2020-68
Abstract: Abstract. The Eocene-Oligocene transition (EOT) from a largely ice-free greenhouse world to an icehouse climate with the first major glaciation of Antarctica was a phase of major climate and environmental change occurring ~34 million years ago (Ma) and lasting ~500 kyr. The change is marked by a global shift in deep sea δ18O representing a combination of deep-ocean cooling and global ice sheet growth. At the same time, multiple independent proxies for sea surface temperature indicate a surface ocean cooling, and major changes in global fauna and flora record a shift toward more cold-climate adapted species. The major explanations of this transition that have been suggested are a decline in atmospheric CO2, and changes to ocean gateways, while orbital forcing likely influenced the precise timing of the glaciation. This work reviews and synthesises proxy evidence of paleogeography, temperature, ice sheets, ocean circulation, and CO2 change from the marine and terrestrial realms. Furthermore, we quantitatively compare proxy records of change to an ensemble of model simulations of temperature change across the EOT. The model simulations compare three forcing mechanisms across the EOT: CO2 decrease, paleogeographic changes, and ice sheet growth. We find that CO2 forcing provides by far the best explanation of the combined proxy evidence, and based on our model ensemble, we estimate that a CO2 decrease of about 1.6× across the EOT (e.g. from 910 to 560 ppmv) achieves the best fit to the temperature change recorded in the proxies. This model-derived CO2 decrease is consistent with proxy estimates of CO2 decline at the EOT.
Publisher: Unpublished
Date: 2017
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Location: Germany
Location: Australia
Location: No location found
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2014
End Date: 2017
Funder: Cooperative Research Centres, Australian Government Department of Industry
View Funded ActivityStart Date: 2020
End Date: 2020
Funder: University of New England
View Funded ActivityStart Date: 2018
End Date: 2019
Funder: Department of Industry, Tourism and Trade
View Funded ActivityStart Date: 2019
End Date: 2021
Funder: Secretariat of the Pacific Regional Environment Programme
View Funded ActivityStart Date: 2017
End Date: 2020
Funder: Centre for International Forestry Research
View Funded Activity