Martin Nolan

Australia is ‘free to choose’ economic growth and falling environmental pressures

Over two centuries of economic growth have put undeniable pressure on the ecological systems that underpin human well-being. While it is agreed that these pressures are increasing, views divide on how they may be alleviated. Some suggest technological advances will automatically keep us from transgressing key environmental thresholds; others that policy reform can reconcile economic and ecological goals; while a third school argues that only a fundamental shift in societal values can keep human demands within the Earth’s ecological limits. Here we use novel integrated analysis of the energy–water–food nexus, rural land use (including biodiversity), material flows and climate change to explore whether mounting ecological pressures in Australia can be reversed, while the population grows and living standards improve. We show that, in the right circumstances, economic and environmental outcomes can be decoupled. Although economic growth is strong across all scenarios, environmental performance varies widely: pressures are projected to more than double, stabilize or fall markedly by 2050. However, we find no evidence that decoupling will occur automatically. Nor do we find that a shift in societal values is required. Rather, extensions of current policies that mobilize technology and incentivize reduced pressure account for the majority of differences in environmental performance. Our results show that Australia can make great progress towards sustainable prosperity, if it chooses to do so.

Bringing ecosystem services into integrated water resources management

In this paper we propose an ecosystem service framework to support integrated water resource management and apply it to the Murray-Darling Basin in Australia. Water resources in the Murray-Darling Basin have been over-allocated for irrigation use with the consequent degradation of freshwater ecosystems. In line with integrated water resource management principles, Australian Government reforms are reducing the amount of water diverted for irrigation to improve ecosystem health. However, limited understanding of the broader benefits and trade-offs associated with reducing irrigation diversions has hampered the planning process supporting this reform. Ecosystem services offer an integrative framework to identify the broader benefits associated with integrated water resource management in the Murray-Darling Basin, thereby providing support for the Government to reform decision-making. We conducted a multi-criteria decision analysis for ranking regional potentials to provide ecosystem services at river basin scale. We surveyed the wider public about their understanding of, and priorities for, managing ecosystem services and then integrated the results with spatially explicit indicators of ecosystem service provision. The preliminary results of this work identified the sub-catchments with the greatest potential synergies and trade-offs of ecosystem service provision under the integrated water resources management reform process. With future development, our framework could be used as a decision support tool by those grappling with the challenge of the sustainable allocation of water between irrigation and the environment.

Modelling Australian land use competition and ecosystem services with food price feedbacks at high spatial resolution

In a globalised world, land use change outlooks are influenced by both locally heterogeneous land attributes and world markets. We demonstrate the importance of high resolution land heterogeneity representation in understanding local impacts of future global scenarios with carbon markets and land competition influencing food prices. A methodologically unique Australian continental model is presented with bottom-up parcel scale granularity in land use change, food, carbon, water, and biodiversity ecosystem service supply determination, and partial equilibrium food price impacts of land competition. We show that food price feedbacks produce modest aggregate national land use and ecosystem service supply changes. However, high resolution results show amplified land use change and ecosystem service impact in some places and muted impacts in other areas relative to national averages. We conclude that fine granularity modelling of geographic diversity produces local land use change and ecosystem service impact insights not discernible with other approaches. We modeled Australian land use change and ecosystem service responses to global scenarios.The model features a novel approach to very high resolution land heterogeneity representation.To demonstrate, we model how food price feedbacks of land competition differ spatially.Modest land use change and ecosystem service impacts are observed in aggregate for Australia.High resolution impacts vary from large to minuscule depending on local land heterogeneity.

Land use efficiency: anticipating future demand for land‐sector greenhouse gas emissions abatement and managing trade‐offs with agriculture, water, and biodiversity

Competition for land is increasing, and policy needs to ensure the efficient supply of multiple ecosystem services from land systems. We modelled the spatially explicit potential future supply of ecosystem services in Australias intensive agricultural land in response to carbon markets under four global outlooks from 2013 to 2050. We assessed the productive efficiency of greenhouse gas emissions abatement, agricultural production, water resources, and biodiversity services and compared these to production possibility frontiers (PPFs). While interacting commodity markets and carbon markets produced efficient outcomes for agricultural production and emissions abatement, more efficient outcomes were possible for water resources and biodiversity services due to weak price signals. However, when only two objectives were considered as per typical efficiency assessments, efficiency improvements involved significant unintended trade-offs for the other objectives and incurred substantial opportunity costs. Considering multiple objectives simultaneously enabled the identification of land use arrangements that were efficient over multiple ecosystem services. Efficient land use arrangements could be selected that meet societys preferences for ecosystem service provision from land by adjusting the metric used to combine multiple services. To effectively manage competition for land via land use efficiency, market incentives are needed that effectively price multiple ecosystem services.

Ecohydrological and socioeconomic integration for the operational management of environmental flows

Investment in and operation of flow control infrastructure such as dams, weirs, and regulators can help increase both the health of regulated river ecosystems and the social values derived from them. This requires high-quality and high-resolution spatiotemporal ecohydrological and socioeconomic information. We developed such an information base for integrated environmental flow management in the River Murray in South Australia (SA). A hydrological model was used to identify spatiotemporal inundation dynamics. River ecosystems were classified and mapped as ecohydrological units. Ecological response models were developed to link three aspects of environmental flows (flood duration, timing, and inter-flood period) to the health responses of 16 ecological components at various life stages. Potential infrastructure investments (flow control regulators and irrigation pump relocation) were located by interpreting LiDAR elevation data, digital orthophotography, and wetland mapping information; and infrastructure costs were quantified using engineering cost models. Social values were quantified at a coarse scale as total economic value based on a national survey of willingness-to-pay for four key ecological assets; and at a local scale using mapped ecosystem service values. This information was integrated using a constrained, nonlinear, mixed-integer, compromise programming optimization model and solved using a stochastic Tabu search algorithm. We tested the model uncertainty and sensitivity using 390 Monte Carlo model runs at varying weights of ecological health vs. social values. Integrating ecohydrological and socioeconomic information identified environmental flow management regimes that efficiently achieved both ecological and social objectives. Using an ecologically weighted efficient and socially weighted efficient scenario, we illustrated model outputs including a suite of cost-effective infrastructure investments and an operational plan for new and existing flow control structures including dam releases, weir height manipulation, and regulator operation on a monthly time step. Both the investments and management regimes differed substantially between the two scenarios, suggesting that the choice of weightings on ecological and social objectives is important. This demonstrates the benefit of integrating high-quality and high-resolution spatiotemporal ecohydrological and socioeconomic information for guiding the investment in and operational management of environmental flows.

Combined Aggregation and Column Generation for Land-Use Trade-Off Optimisation

In this paper we developed a combination of aggregation-disaggregation technique with the concept of column generation to solve a large scale LP problem originating from land use management in the Australian agricultural sector. The problem is to optimally allocate the most profitable land use activities including agriculture, carbon sequestration, environmental planting, bio-fuel, bio-energy, etc., and is constrained to satisfy some food demand considerations and expansion policies for each year from 2013 to 2050. In this research we produce a higher resolution solution by dividing Australia’s agricultural areas into square kilometer cells, which leads to more than thirteen million cells to be assigned, totally or partially, to different activities. By accepting a scenario on agricultural products’ return, carbon related activities, future energy prices, water availability, global climate change, etc. a linear programming problem is composed for each year. However, even by using a state of the art commercial LP solver it takes a long time to find an optimal solution for one year. Therefore, it is almost impossible to think about simultaneous scenarios to be incorporated, as the corresponding model will become even larger. Based on the properties of the problem, such as similar economical and geographical properties of nearby land parcels, the combination of clustering ideas with column generation to decompose the large problem into smaller sub-problems yields a computationally efficient algorithm for the large scale problem.

From Water-Use to Water-Scarcity Footprinting in Environmentally Extended Input–Output Analysis

Environmentally extended input-output analysis (EEIOA) supports environmental policy by quantifying how demand for goods and services leads to resource use and emissions across the economy. However, some types of resource use and emissions require spatially explicit impact assessment for meaningful interpretation, which is not possible in conventional EEIOA. For example, water use in locations of scarcity and of abundance are not environmentally equivalent. Opportunities for spatially explicit impact assessment in conventional EEIOA are limited because official input-output tables tend to be produced at the scale of political units, which are not usually well-aligned with environmentally relevant spatial units. In this study, spatially explicit water-scarcity factors and a spatially disaggregated Australian water-use account were used to develop water-scarcity extensions that were coupled with a multiregional input-output model (MRIO). The results link demand for agricultural commodities to the problem of water scarcity in Australia and globally. Important differences were observed between the water-use and water-scarcity footprint results as well as the relative importance of direct and indirect water use, with significant implications for sustainable production and consumption-related policies. The approach presented here is suggested as a feasible general approach for incorporating spatially explicit impact assessments in EEIOA.