Browsing by Author "Gergis, J"

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    Increasing the understanding and use of natural archives of ecosystem services, resilience and threholds to improve policy, science and practice
    (SAGE, 2014-12-04) Pearson, S; Lynch, AJJ; Plant, R; Cork, S; Taffs, K; Dodson, JR; Maynard, S; Gergis, J; Gell, PA; Thackway, R; Sealie, L; Donaldson, J
    Despite the great potential of palaeo-environmental information to strengthen natural resource policy, science and practical outcomes naturally occurring archives of palaeo-environmental and ecosystem service information have not been fully recognised or utilised to inform the development of environmental policy. In this paper, we describe how Australian palaeo-environmental science is improving environmental understanding through local studies and regional syntheses that inform us about past conditions, extreme conditions and altered ecosystem states. Australian innovations in ecosystem services research and palaeo-environmental science contribute in five important contexts: discussions about environmental understanding and management objectives, improving access to information, improved knowledge about the dynamics of ecosystem services, increasing understanding of environmental processes and resource availability, and engaging interdisciplinary approaches to manage ecosystem services. Knowledge of the past is an important starting point for setting present and future resource management objectives, anticipating consequences of trade-offs, sharing risk and evaluating and monitoring the ongoing availability of ecosystem services. Palaeo-environmental information helps reframe discussions about desirable futures and collaborative efforts between scientists, planners, managers and communities. However, further steps are needed to translate the ecosystem services concept into ecosystem services policy and tangible management objectives and actions that are useful, feasible and encompass the range of benefits to people from ecosystems. We argue that increased incorporation of palaeo-environmental information into policy and decision-making is needed for evidence-based adaptive management to enhance sustainability of ecosystem functions and reduce long-term risks. © 2020 by SAGE Publications
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    Paleoclimate data-model comparison and the role of climate forcings over the past 1500 Years
    (American Meterological Society, 2013-09-01) Phipps, SJ; McGregor, HV; Gergis, J; Gallant, AJE; Neukom, R; Stevenson, S; Ackerley, D; Brown, JR; Fischer, MJ; van Ommen, TD
    The past 1500 years provide a valuable opportunity to study the response of the climate system to external forcings. However, the integration of paleoclimate proxies with climate modeling is critical to improving the understanding of climate dynamics. In this paper, a climate system model and proxy records are therefore used to study the role of natural and anthropogenic forcings in driving the global climate. The inverse and forward approaches to paleoclimate data-model comparison are applied, and sources of uncertainty are identified and discussed. In the first of two case studies, the climate model simulations are compared with multiproxy temperature reconstructions. Robust solar and volcanic signals are detected in Southern Hemisphere temperatures, with a possible volcanic signal detected in the Northern Hemisphere. The anthropogenic signal dominates during the industrial period. It is also found that seasonal and geographical biases may cause multiproxy reconstructions to overestimate the magnitude of the long-term preindustrial cooling trend. In the second case study, the model simulations are compared with a coral O-18 record from the central Pacific Ocean. It is found that greenhouse gases, solar irradiance, and volcanic eruptions all influence the mean state of the central Pacific, but there is no evidence that natural or anthropogenic forcings have any systematic impact on El Nino-Southern Oscillation. The proxy climate relationship is found to change over time, challenging the assumption of stationarity that underlies the interpretation of paleoclimate proxies. These case studies demonstrate the value of paleoclimate data-model comparison but also highlight the limitations of current techniques and demonstrate the need to develop alternative approaches. © 2013, American Meteorological Society.
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    Paleoclimate studies and natural-resource management in the Murray-Darling Basin II: unravelling human impacts and climate variability
    (Taylor and Francis Group, 2013-08-09) Mills, K; Gell, PA; Gergis, J; Baker, PJ; Finlayson, CM; Hesse, PP; Jones, R; Kershaw, P; Pearson, S; Treble, PC; Barr, C; Brookhouse, MT; Drysdale, RN; McDonald, J; Haberle, SG; Reid, M; Thoms, M; Tibby, J
    The management of the water resources of the Murray-Darling Basin (MDB) has long been contested, and the effects of the recent Millennium drought and subsequent flooding events have generated acute contests over the appropriate allocation of water supplies to agricultural, domestic and environmental uses. This water-availability crisis has driven demand for improved knowledge of climate change trends, cycles of variability, the range of historical climates experienced by natural systems and the ecological health of the system relative to a past benchmark. A considerable volume of research on the past climates of southeastern Australia has been produced over recent decades, but much of this work has focused on longer geological time-scales, and is of low temporal resolution. Less evidence has been generated of recent climate change at the level of resolution that accesses the cycles of change relevant to management. Intra-decadal and near-annual resolution (high-resolution) records do exist and provide evidence of climate change and variability, and of human impact on systems, relevant to natural-resource management. There exist now many research groups using a range of proxy indicators of climate that will rapidly escalate our knowledge of management-relevant, climate change and variability. This review assembles available climate and catchment change research within, and in the vicinity of, the MDB and portrays the research activities that are responding to the knowledge need. It also discusses how paleoclimate scientists may better integrate their pursuits into the resource-management realm to enhance the utility of the science, the effectiveness of the management measures and the outcomes for the end users. © 2020 Informa UK Limited
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    Solar and volcanic forcing of the Southern Hemisphere climate over the past 1500 years
    (Past Global Changes, 2013-02-13) Phipps, SJ; Ackerley, D; Brown, JR; Curran, MAJ; Fischer, MJ; Gallant, A; Gergis, J; McGregor, HV; Neukom, R; Plummer, C; Stevenson, S; van Ommen, TD
    The past 1500 years provides a valuable opportunity to study the role of external forcings in driving the global climate. Significant changes have taken place within the climate system over this period, and proxy data that records these changes covers a wide geographical area and has high temporal resolution. Natural and anthropogenic forcings are also reasonably well constrained. While previous detection and attribution studies have found a significant role of volcanic eruptions in driving the pre-industrial Northern Hemisphere climate, the drivers of the Southern Hemisphere climate are much less well understood. Here, the CSIRO Mk3L climate system model is used to simulate the global climate of the past 1500 years. Different combinations of natural and anthropogenic forcings are applied, including changes in the Earth’s orbital parameters, solar irradiance, volcanic emissions and anthropogenic greenhouse gases. The simulations are then compared with a multi-proxy reconstruction of Southern Hemisphere temperature. We find strong solar and volcanic influences on the Southern Hemisphere climate during the pre-industrial period, with the anthropogenic signal becoming increasingly dominant after 1850 CE. However, the results are sensitive to the specific reconstructions of solar and volcanic activity that are used to drive the model. The choice of volcanic reconstruction is particularly critical, and we find that the dating of major eruptions can impact significantly upon the agreement between the model and the proxy record. If we are to learn all that we can from the climate of recent millennia, a critical challenge is therefore to develop better reconstructions of past climatic forcings − particularly volcanic eruptions.