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AbstractBioenergy projects can lead to direct and indirect land use change (LUC), which can substantially affect greenhouse gas balances with both beneficial and adverse outcomes for bioenergy's contribution to climate change mitigation. The causes behind LUC are multiple, complex, interlinked, and change over time. This makes quantification uncertain and sensitive to many factors that can develop in different directions—including land use productivity, trade patterns, prices and elasticities, and use of by‐products associated with biofuels production. Quantifications reported so far vary substantially and do not support the ranking of bioenergy options with regard to LUC and associated emissions. There are however several options for mitigating these emissions, which can be implemented despite the uncertainties. Long‐rotation forest management is associated with carbon emissions and sequestration that are not in temporal balance with each other and this leads to mitigation trade‐offs between biomass extraction for energy use and the alternative to leave the biomass in the forest. Bioenergy's contribution to climate change mitigation needs to reflect a balance between near‐term targets and the long‐term objective to hold the increase in global temperature below 2°C (Copenhagen Accord). Although emissions from LUC can be significant in some circumstances, the reality of such emissions is not sufficient reason to exclude bioenergy from the list of worthwhile technologies for climate change mitigation. Policy measures to minimize the negative impacts of LUC should be based on a holistic perspective recognizing the multiple drivers and effects of LUC.This article is categorized under: Bioenergy > Economics and Policy Bioenergy > Climate and Environment

AbstractBioenergy projects can lead to direct and indirect land use change (LUC), which can substantially affect greenhouse gas balances with both beneficial and adverse outcomes for bioenergy's contribution to climate change mitigation. The causes behind LUC are multiple, complex, interlinked, and change over time. This makes quantification uncertain and sensitive to many factors that can develop in different directions—including land use productivity, trade patterns, prices and elasticities, and use of by‐products associated with biofuels production. Quantifications reported so far vary substantially and do not support the ranking of bioenergy options with regard to LUC and associated emissions. There are however several options for mitigating these emissions, which can be implemented despite the uncertainties. Long‐rotation forest management is associated with carbon emissions and sequestration that are not in temporal balance with each other and this leads to mitigation trade‐offs between biomass extraction for energy use and the alternative to leave the biomass in the forest. Bioenergy's contribution to climate change mitigation needs to reflect a balance between near‐term targets and the long‐term objective to hold the increase in global temperature below 2°C (Copenhagen Accord). Although emissions from LUC can be significant in some circumstances, the reality of such emissions is not sufficient reason to exclude bioenergy from the list of worthwhile technologies for climate change mitigation. Policy measures to minimize the negative impacts of LUC should be based on a holistic perspective recognizing the multiple drivers and effects of LUC.This article is categorized under: Bioenergy > Economics and Policy Bioenergy > Climate and Environment

Climate change poses a serious threat to the long-term structural integrity, if not existence, of the Australian constitutional system. This means that Australian government action worsening climate change poses a threat to this constitutional system. When government action threatens this system, even in a partial or incremental manner, the High Court may derive implications from the Commonwealth Constitution (‘Constitution’) to restrain such action. This is the reasoning underpinning the Court’s establishment of implied limitations such as the Melbourne Corporation and political communication limitations. Based on this reasoning, I explore in this thesis whether a doctrinal argument can be made for deriving a new implication from the Constitution that I refer to as the ‘ecological limitation’. This limitation, if established, would restrain some forms of Commonwealth or State legislative and executive action worsening climate change in the interests of preserving the Australian constitutional system. My methodology for assessing the doctrinal merits of this proposed implication is framed by the High Court’s ‘text and structure approach’ articulated in Lange v Australian Broadcasting Corporation (1997) 189 CLR 520. This interpretive approach requires implications to be derived from the text and structure of the Constitution. I supplement this approach by drawing comparisons between the ecological limitation and established implications to gain further insights on what aspects of a proposed implication may be deemed acceptable and unacceptable by the Court. Finally, I tease out the operation of the ecological limitation by considering its hypothetical application in relation to a real occurrence. Namely, I consider how the limitation might apply to restrain Queensland government approval of a proposed coal mine – the Carmichael mine currently being pursued by Adani Mining Pty Ltd. By following this methodology, I arrive at the doctrinal argument for deriving the ecological limitation outlined above and assess the doctrinal arguments against its derivation that might be raised in response (such as concerns regarding the political decision-making judges would have to engage in if the limitation is established). I conclude that a compelling doctrinal case can be made in support of the ecological limitation that can withstand these counter-arguments.

Climate change poses a serious threat to the long-term structural integrity, if not existence, of the Australian constitutional system. This means that Australian government action worsening climate change poses a threat to this constitutional system. When government action threatens this system, even in a partial or incremental manner, the High Court may derive implications from the Commonwealth Constitution (‘Constitution’) to restrain such action. This is the reasoning underpinning the Court’s establishment of implied limitations such as the Melbourne Corporation and political communication limitations. Based on this reasoning, I explore in this thesis whether a doctrinal argument can be made for deriving a new implication from the Constitution that I refer to as the ‘ecological limitation’. This limitation, if established, would restrain some forms of Commonwealth or State legislative and executive action worsening climate change in the interests of preserving the Australian constitutional system. My methodology for assessing the doctrinal merits of this proposed implication is framed by the High Court’s ‘text and structure approach’ articulated in Lange v Australian Broadcasting Corporation (1997) 189 CLR 520. This interpretive approach requires implications to be derived from the text and structure of the Constitution. I supplement this approach by drawing comparisons between the ecological limitation and established implications to gain further insights on what aspects of a proposed implication may be deemed acceptable and unacceptable by the Court. Finally, I tease out the operation of the ecological limitation by considering its hypothetical application in relation to a real occurrence. Namely, I consider how the limitation might apply to restrain Queensland government approval of a proposed coal mine – the Carmichael mine currently being pursued by Adani Mining Pty Ltd. By following this methodology, I arrive at the doctrinal argument for deriving the ecological limitation outlined above and assess the doctrinal arguments against its derivation that might be raised in response (such as concerns regarding the political decision-making judges would have to engage in if the limitation is established). I conclude that a compelling doctrinal case can be made in support of the ecological limitation that can withstand these counter-arguments.

River deltas and estuaries are disproportionally-significant coastal landforms that are inhabited by nearly 600 M people globally. In recent history, rapid socio-economic development has dramatically changed many of the World's mega deltas, which have typically undergone agricultural intensification and expansion, land-use change, urbanization, water resources engineering and exploitation of natural resources. As a result, mega deltas have evolved into complex and potentially vulnerable socio-ecological systems with unique threats and coping capabilities. The goal of this research was to establish a holistic understanding of threats, resilience, and adaptation for four mega deltas of variable geography and levels of socio-economic development, namely the Mekong, Yellow River, Yangtze, and Rhine deltas. Compiling this kind of information is critical for managing and developing these complex coastal areas sustainably but is typically hindered by a lack of consistent quantitative data across the ecological, social and economic sectors. To overcome this limitation, we adopted a qualitative approach, where delta characteristics across all sectors were assessed through systematic expert surveys. This approach enabled us to generate a comparative assessment of threats, resilience, and resilience-strengthening adaptation across the four deltas. Our assessment provides novel insights into the various components that dominate the overall risk situation in each delta and, for the first time, illustrates how each of these components differ across the four mega deltas. As such, our findings can guide a more detailed, sector specific, risk assessment or assist in better targeting the implementation of risk mitigation and adaptation strategies.

River deltas and estuaries are disproportionally-significant coastal landforms that are inhabited by nearly 600 M people globally. In recent history, rapid socio-economic development has dramatically changed many of the World's mega deltas, which have typically undergone agricultural intensification and expansion, land-use change, urbanization, water resources engineering and exploitation of natural resources. As a result, mega deltas have evolved into complex and potentially vulnerable socio-ecological systems with unique threats and coping capabilities. The goal of this research was to establish a holistic understanding of threats, resilience, and adaptation for four mega deltas of variable geography and levels of socio-economic development, namely the Mekong, Yellow River, Yangtze, and Rhine deltas. Compiling this kind of information is critical for managing and developing these complex coastal areas sustainably but is typically hindered by a lack of consistent quantitative data across the ecological, social and economic sectors. To overcome this limitation, we adopted a qualitative approach, where delta characteristics across all sectors were assessed through systematic expert surveys. This approach enabled us to generate a comparative assessment of threats, resilience, and resilience-strengthening adaptation across the four deltas. Our assessment provides novel insights into the various components that dominate the overall risk situation in each delta and, for the first time, illustrates how each of these components differ across the four mega deltas. As such, our findings can guide a more detailed, sector specific, risk assessment or assist in better targeting the implementation of risk mitigation and adaptation strategies.

Nearly 50% of global energy consumption is associated with meeting thermal requirements. Whilst some of this is heat goes to low temperature applications like hot water supply, there is also a huge demand for the supply of 100-250oC thermal energy for industrial and commercial applications which is currently met by gas and electricity. However, using innovative optical and thermal technologies, it can also (potentially) be met by concentrated sunlight from urban rooftop collectors, eliminating billions of kg of CO2 emissions per year. Hence, it may be possible to develop new, advanced collectors to substantially increase the amount of commercial rooftop solar energy harvesting. At present, though, there are still some barriers to overcome to successfully collect large scale of 100-250oC thermal energy from rooftops. One key barrier for most concentrated solar systems is that integration with rooftops is relatively complex and cumbersome in comparison with photovoltaic (PV) panels. This requires a new type of concentrator which is efficient, low-cost and has a low-wind/aesthetic profile. These criteria point to thin concentrators that can be rack-mounted or laid flat on the roof with minimal balance of system requirements. The system should have similar geometrical features and appearance to PV panels and non-concentrating solar hot water collection panels, which are by far the most widely deployed solar collection systems to date. Such a concentrating collector has yet to be demonstrated. As such, this study aims to advancing rooftop solar concentrating technology for commercial and industrial applications via the development of thin optical elements which avoid rotational tracking. During the course of the research, several innovative low-profile optical concentrators (<15cm in height) were designed, developed and systematically investigated to demonstrate their potential to deliver heat energy in the 100-250oC range. A series of experiments were conducted to validate these compact optical concentrator concepts and to demonstrate their performance as semi-passive, internal tracking and concentrating. An economic analysis was also performed to evaluate the feasibility of the final, optimized design proposed in this thesis. Overall, this study offers new optical platforms to advance the utilization of solar energy in urban areas.

Nearly 50% of global energy consumption is associated with meeting thermal requirements. Whilst some of this is heat goes to low temperature applications like hot water supply, there is also a huge demand for the supply of 100-250oC thermal energy for industrial and commercial applications which is currently met by gas and electricity. However, using innovative optical and thermal technologies, it can also (potentially) be met by concentrated sunlight from urban rooftop collectors, eliminating billions of kg of CO2 emissions per year. Hence, it may be possible to develop new, advanced collectors to substantially increase the amount of commercial rooftop solar energy harvesting. At present, though, there are still some barriers to overcome to successfully collect large scale of 100-250oC thermal energy from rooftops. One key barrier for most concentrated solar systems is that integration with rooftops is relatively complex and cumbersome in comparison with photovoltaic (PV) panels. This requires a new type of concentrator which is efficient, low-cost and has a low-wind/aesthetic profile. These criteria point to thin concentrators that can be rack-mounted or laid flat on the roof with minimal balance of system requirements. The system should have similar geometrical features and appearance to PV panels and non-concentrating solar hot water collection panels, which are by far the most widely deployed solar collection systems to date. Such a concentrating collector has yet to be demonstrated. As such, this study aims to advancing rooftop solar concentrating technology for commercial and industrial applications via the development of thin optical elements which avoid rotational tracking. During the course of the research, several innovative low-profile optical concentrators (<15cm in height) were designed, developed and systematically investigated to demonstrate their potential to deliver heat energy in the 100-250oC range. A series of experiments were conducted to validate these compact optical concentrator concepts and to demonstrate their performance as semi-passive, internal tracking and concentrating. An economic analysis was also performed to evaluate the feasibility of the final, optimized design proposed in this thesis. Overall, this study offers new optical platforms to advance the utilization of solar energy in urban areas.

The primary question explored by this thesis is what alternative, carbon tax or emissions trading, would be an optimal policy for climate change mitigation in Australia. This thesis focuses on assessing carbon tax and emissions trading policy options on the basis of multiple criteria related to climate change policy in the Australian context. The study analyses the issues of environmental degradation, policy responses to the climate change issue, carbon taxation and emissions trading as a theoretical foundation for addressing the research question. The weaknesses of common evaluation methods and practices in dealing with climate change policy are also critiqued. After reviewing policy evaluation methods, the study builds a methodological framework to assess the climate change policy options based on the multi-criteria and Delphi methods. To facilitate the evaluation procedure, the criteria necessary for the climate change policy evaluation are identified. This study employs the Delphi method to verify the evaluation criteria in the Australian context and to assess the relative importance of these criteria. The thesis also attempts to construct carbon tax and emissions trading policies for Australia using a combination of theoretical and practical considerations. Further, these two contrasting policies are qualitatively analysed with reference to the identified criteria to assess potential performance of the proposed carbon tax and emissions trading. The resultant evaluation criteria and performance ranks of each proposed policy option allows building a decision matrix which facilitates the final evaluation and selection of an optimal policy. The evaluation results reveal that the carbon tax policy constructed by this study outperforms the designed emissions trading in terms of many criteria. As a result, the carbon tax is identified as an optimal climate change mitigation policy for Australia. The results of this study also indicate that the emissions trading proposed by the Australian Government might be a misleading policy founded on biased assumptions. Based on these findings it is recommended that Australia reconsider carbon tax and emissions trading policies on the basis of well developed multiple criteria to obtain a justified and sustained policy solution.