Search

Increasing the adoption of energy-efficiency measures (EEM) by households is one of the practical strategies to increase energy efficiency and reduce greenhouse gas emissions. For the 3.24 million low-income households in Australia, partly due to their potentially disproportionately large waste of usable energy, there is a gap between the potential for energy efficiency through existing EEM and the actual energy-efficiency level. Many measures increase energy efficiency in buildings; however, barriers persist for such households to adopt these measures, of which limited research has yet to be conducted. In response, this study examines the relationships involved by a questionnaire survey of 212 low-income households in Australia, showing that financial barriers have the greatest influence followed by split incentive barriers, with the provision of information having no significant role to play. This paper contributes to filling the gap of limited energy-efficiency research involving low-income households, revealing the effect of energy-efficiency barriers on their adoption of EEM. [ABSTRACT FROM AUTHOR]

Planetary health equity – the equitable enjoyment of good health and wellbeing in a sustainable ecosystem – is under threat from anthropogenic climate change and economic and social inequities. Driving these major challenges is the global consumptogenic system that encourages excessive production and consumption goods and services that are harming human and planetary health. Growth models lie at the core of the consumptogenic system. This paper examines the sources of economic growth in Australia, the coalitions that sustain this approach politically, and the implications of these dynamics for planetary health equity. Australia's consumption-led growth model is underpinned by a combination of rising house prices and a permissive credit regime. This growth model is supported by a dominant growth coalition of producer interests, elements of organised labour, and property owners. The growth coalition has been able to successfully generate growth model policy convergence between the mainstream political parties. In turn this growth model, and associated growth coalition, has undermined the pursuit of planetary health equity in Australia by incentivising and driving excessive consumption, greenhouse gas emissions, and economic inequality. [ABSTRACT FROM AUTHOR]

Analysis of observations, reanalysis, and model simulations, including those using machine learning methods specifically designed for regime identification, has revealed changes in aspects of the Southern Hemisphere (SH) circulation and Australian climate and extremes over the last half-century that indicate transitions to new states. In particular, our analysis shows a dramatic shift in the metastability of the SH climate that occurred in the late 1970s, associated with a large-scale regime transition in the SH atmospheric circulation, with systematic changes in the subtropical jet, blocking, zonal winds, and storm tracks. Analysis via nonstationary clustering reveals a regime shift coincident with a sharp transition to warmer oceanic sea surface temperatures and increased baroclinicity in the large scales of the Antarctic Circumpolar Circulation (ACC), extending across the whole hemisphere. At the same time, the background state of the tropical Pacific thermocline shoaled, leading to an increased likelihood of El Niño events. The SH climate shift in the late 1970s is the first hemispheric regime shift that can be directly attributed to anthropogenic climate change. These changes in dynamics are associated with additional regional tipping points, including reductions in mean and extreme rainfall in south-west Western Australia (SWWA) and streamflow into Perth dams, and also with increases in mean and extreme rainfall over northern Australia since the late 1970s. The drying of south-eastern Australia (SEA) occurred against a background of accelerating increases in average and extreme temperatures across the whole continent since the 1990s, implying further inflection points may have occurred. Analysis of climate model simulations capturing the essence of these observed shifts indicates that these systematic changes will continue into the late 21st century under high greenhouse gas emission scenarios. Here, we review two decades of work, revealing for the first time that tipping points characteristic of regime transitions are inferred to have already occurred in the SH climate system. [ABSTRACT FROM AUTHOR]

Estuaries play an important role in connecting the global carbon cycle across the land-to-ocean continuum, but little is known about Australia's contribution to global CO2 emissions. Here we present an Australia-wide assessment, based on CO2 concentrations for 47 estuaries upscaled to 971 assessed Australian estuaries. We estimate total mean (±SE) estuary CO2 emissions of 8.67 ± 0.54 Tg CO2-C yr−1, with tidal systems, lagoons, and small deltas contributing 94.4%, 3.1%, and 2.5%, respectively. Although higher disturbance increased water-air CO2 fluxes, its effect on total Australian estuarine CO2 emissions was small due to the large surface areas of low and moderately disturbed tidal systems. Mean water-air CO2 fluxes from Australian small deltas and tidal systems were higher than from global estuaries because of the dominance of macrotidal subtropical and tropical systems in Australia, which have higher emissions due to lateral inputs. We suggest that global estuarine CO2 emissions should be upscaled based on geomorphology, but should also consider land-use disturbance, and climate. Australian estuaries shown to emit more CO2 per unit area than global estuaries due to the dominance of macrotidal subtropical and tropical tidal systems, while disturbance effects were minimal due to low overall disturbance. [ABSTRACT FROM AUTHOR]

Combustion power plants emit carbon dioxide (CO2), which is a major contributor to climate change. Direct emissions measurement is cost-prohibitive globally, while reporting varies in detail, latency, and granularity. To fill this gap and greatly increase the number of power plants worldwide with independent emissions monitoring, we developed and applied machine learning (ML) models using power plant water vapor plumes as proxy signals to estimate electric power generation and CO2 emissions using Landsat 8, Sentinel-2, and PlanetScope imagery. Our ML models estimated power plant activity on each image snapshot, then an aggregation model predicted plant utilization over a 30-day period. Lastly, emission factors specific to region, fuel, and plant technology were used to convert the estimated electricity generation into CO2 emissions. Models were trained with reported hourly electricity generation data in the US, Europe, and Australia and were validated with additional generation and emissions data from the US, Europe, Australia, Türkiye, and India. All results with sufficiently large sample sizes indicate that our models outperformed the baseline approaches. In validating our model results against available generation and emissions reported data, we calculated the root mean square error as 1.75 TWh (236 plants across 17 countries over 4 years) and 2.18 Mt CO2 (207 plants across 17 countries over 4 years), respectively. Ultimately, we applied our ML method to plants that constitute 32% of global power plant CO2 emissions, as estimated by Climate TRACE, averaged over the period 2015–2022. This dataset is the most comprehensive independent and free-of-cost global power plant point-source emissions monitoring system currently known to the authors and is made freely available to the public to support global emissions reduction. [ABSTRACT FROM AUTHOR]

Understanding the change in soil organic carbon (C) stock in a warmer climate and the effect of current land management on that stock is critical for soil and environmental conservation and climate policy. By simulation modeling, we predicted changes in Australia's soil organic C stock from 2010 to 2100. These vary from losses of 0.014–0.077 t C ha−1 year−1 between 2020 and 2045 and 0.013–0.047 t C ha−1 year−1 between 2070 and 2100, under increasing emissions of greenhouse gases and temperature. Thus, Australian soil will be a net emitter of CO2. Depending on the future socio-economic conditions, we predict that croplands will accrue as much as 0.19 t C ha−1 year−1 between 2020 and 2045 due to their management, but accrual will decrease with warming and increased emissions by 2070–2100. The gains will be too small to counteract the losses of C from the larger areas of rangelands and coastal regions that are more sensitive to a warmer climate. In principle, prudent management of the rangelands, for example, improving grazing management and regenerating biodiverse, endemic native plant communities, could sequester more C and mitigate the loss; in practice, it may be more difficult, requiring innovation, interdisciplinary science, cultural awareness and effective policies. [ABSTRACT FROM AUTHOR]

Environmental context: Mine tailings are a mixture of fine materials obtained after crushing, processing and extracting the valuable minerals from ore. Ultramafic and mafic mine tailings have the potential to mineralise carbon, offering a solution to offset greenhouse gas emissions from the mining sector. The study revealed that the effects of wetting and drying ultramafic and mafic mine tailings under atmospheric conditions have the potential for carbon sequestration and acid mine drainage. Rationale: As the result of their carbon mineralisation potential, there is an increasing interest in using ultramafic and mafic (U+M) mine tailings as a feedstock for carbon (C) sequestration. However, little is known about the relative chemical stability of U+M minerals, and it is unclear whether acid mine drainage may be generated during weathering. Methodology: This study determined the relative stability of the constituent minerals of several U+M tailings from mines in British Columbia, Canada, and Australia using selective chemical extractions and an 18-week laboratory experiment of cycles of wetting and drying to simulate conditions that may be experienced under field conditions. Tailings were mixed with topsoil to investigate the potential use as a soil amendment. Results: Initially, the tailing sample's pH was 8.4–9.7 and decreased to 7.7–9.1 over the 18 weeks. Soil additions lowered the initial pH and converged with the tailing's pH over 18 weeks. Sequentially weathered minerals determined by X-ray diffraction were consistent with the empirical Goldich weathering sequence. Metal concentrations from inductively coupled plasma–mass spectrometry supported X-ray diffraction results, confirming the stability of the U+M tailings using different methods and the need for future studies on potential metal contamination. Discussion: Minor concentrations of sulfur seemed to have resulted in larger fluctuations in pH when low amounts of carbonates were present. However, reactive oxides and basic cations in the U+M tailings maintained pH above 7. Therefore, C sequestration was likely supported, although there was a slight reduction in total C content for almost all samples. This study suggests future research is required under field conditions to confirm C sequestration and to investigate the use of U+M tailings for restoration applications. Environmental context. Mine tailings are a mixture of fine materials obtained after crushing, processing and extracting the valuable minerals from ore. Ultramafic and mafic mine tailings have the potential to mineralise carbon, offering a solution to offset greenhouse gas emissions from the mining sector. The study revealed that the effects of wetting and drying ultramafic and mafic mine tailings under atmospheric conditions have the potential for carbon sequestration and acid mine drainage. [ABSTRACT FROM AUTHOR]