Search

The Forest Fire Danger Index (FFDI) is the main measure used in Australia for estimating fire risk. Recent work by the authors showed that the FFDI forms stable state regimes, nominated as fire climate regimes. These regimes shifted to greater intensity in southern and eastern Australia around the year 2000 and, a decade later, further north. Reductions in atmospheric moisture were the primary contributor. These changes have not been fully incorporated into future projections. This paper compares the recent regime shifts with the most recent national projections of FFDI, published in 2015. They show that for most states and regions, the 2030 upper limit is approached or exceeded by the recent shift, except for two states with large arid zones, South Australia and Western Australia. Methods for attributing past changes, constructing projections, and the inability of climate models to reproduce the recent decreases in atmospheric moisture, all contribute to these underestimates. To address these shortcomings, we make some suggestions to modify efforts aiming to develop seamless predictions and projections of future fire risk. [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]

With increasing numbers of parents choosing to home-school their child, currently there is very limited information about how this is implemented. Utilizing the recently developed Parents' Perceptions of Home-Schooling scale (PPHS), a survey of 93 home-schooling parents in Western Australia was undertaken. Data were collected using five Likert scales to obtain information concerned with a range of implementation aspects. Key findings were related to the process for registering and providing an appropriate learning program, the role of the home-educator moderator, the type of study and support utilized, and whether the student had a disability or ALNs. The discussion considers links to inclusion and how the heightened uptake of home-schooling can be monitored effectively. [ABSTRACT FROM AUTHOR]

The global construction sector contributes a significant share of total greenhouse gas (GHG) emissions. In Australia, infrastructure activity alone generates 18% of the GHG emissions. The use of low-embodied carbon building materials is crucial to decarbonise the construction sector and fulfil national and international climate goals. Industrial hemp (Cannabis sativa L.) is a promising feedstock for low-carbon construction materials because of its carbon sequestration capacity, fast-growing cycles, and technical functionality comparable to traditional materials. This study utilised the life cycle assessment (LCA) guideline ISO 14040:2006 to estimate the carbon footprint (CF) of hemp-based building materials in Western Australia capturing region-specific variations in terms of inputs, soil, productivity, and energy mix. The functional unit was 1 m2 of a hemp-based board, and the system boundary was cradle-to-gate, i.e., pre-farm, on-farm, and post-farm activities. The CF of 1 m2 of hemp-based board was estimated to be −2.302 kg CO2 eq. Electricity from the public grid for bio-based binder production during the post-farm stage was the main contributor to total CO2 eq emissions (26%), followed by urea production (14%) during the pre-farm stage. Overall, the use of electricity from the public grid during the post-farm stage accounted for 45% of total emissions. Sensitivity analysis showed that the CF of hemp-based boards was highly sensitive to the source of energy; i.e., total replacement of the public grid by solar power decreased the CF by 164% (−2.30 to −6.07 kg CO2 eq). The results suggested that hemp-based boards exhibit lower embodied GHG emissions compared to traditional materials, such as gypsum plasterboards. [ABSTRACT FROM AUTHOR]

We analysed changes in magnitude and timing of the largest annual observed daily flow (Amax), in each water year, for 596 stations in high-value water resource catchments and flood risk locations across Australia. These stations are either included in the Bureau of Meteorology's Hydrologic Reference Stations or used in its operational flood forecasting services. Monotonic trend (which is either consistently increasing or decreasing) analyses of the magnitude and timing of flood peaks (estimated using Amax) were performed using the Theil–Sen and Mann–Kendall approaches and circular statistics to identify the strength of seasonality and timing. We analysed regional significance across different drainage divisions using the Walker test. Monotonic decreasing trends in Amax flood magnitude were found in the Murray–Darling River Basin and in other drainage divisions in Victoria, southwest and midwest of Western Australia and South Australia. No significant obvious pattern in Amax magnitude was detected in northern Queensland, coastal NSW, central Australia and Tasmania. Monotonic increasing trends were only found in the Tanami–Timor Sea Coast drainage division in northern Australia. Monotonic trends in Amax magnitude were regionally significant at the drainage division scale. We found two distinct patterns in flood seasonality and timing. In the northern and southern parts of Australia, flood peaks generally occur from February to March and August to October, respectively. The strength of this seasonality varies across the country. Weaker seasonality was detected for locations in the Murray–Darling River Basin, and stronger seasonality was evident in northern Australia, the southwest of Western Australia, South Australia, Victoria and Tasmania. The trends of seasonality and timing reveal that in general, flood peaks have occurred later in the water year in recent years. In northern Australia, flood peaks have generally occurred earlier, at a rate of 12 days/decade. In Victoria, New South Wales and Tasmania, the trends in timing are generally mixed. However, in the southwest of Western Australia, the largest change in timing was evident, with Amax peaks commencing later at a rate of 15 days/decade. Decadal variability in flood timing was found at the drainage division scale as well. Most stations show a decreasing trend in Amax magnitude, but how that trend is associated with the change in timing is not clear. [ABSTRACT FROM AUTHOR]

The jarrah forest is a natural ecosystem with significant endemism in the flora and fauna. The forest stands on the western edge of the ancient Great Plateau of Western Australia on the granitic shield of the Yilgarn craton (2.5 Gya). The long-term migration of soluble iron and aluminium led to the formation of bauxite ore. The regolith ore is bound by surficial topsoil and deep pallid zone kaolinite clays, primarily used in land rehabilitation. We investigated the chemical fertility of the substrates, along with key physical properties. We found the capacity of these soils to provide a stable growth medium differed considerably in their ability to retain and supply nutrients. These substrates are deficient in nitrogen, phosphorus, and micronutrients. In the topsoil, 15% of total P is plant-available, while in the pallid zone layer, only 1% of total P is available. 31P-NMR showed no organic P in the pallid zone, whereas the topsoil had significant organic P and, consequently, a supply of phosphate ions. This shows the importance of organic P in the topsoil for ecosystem nutrition when inorganic fertilisers are not applied in state-of-the-art restoration schemes. [ABSTRACT FROM AUTHOR]

In 2018–2019, 85% of discarded plastics were landfilled in Australia. In Western Australia (WA), only 5.6% of plastics were recovered for reprocessing. With several Asian Countries imposing import restrictions, which were the prime destination for recyclables from Australia, the whole scenario for the waste industry has changed. Australia has now adopted export bans for recyclables, including plastics. WA is at a fork in the road; WA needs to rethink its relationship with plastic materials. This study explores how to create local markets for recycled plastics underpinning circular principles. The study examines barriers and drivers to enable markets for recycled plastics in WA through questionnaires, surveys, and interviews with relevant stakeholders. Poor source separation, low and inconsistent plastic waste feedstock, and virgin plastic competition are some of the challenges, while new investments in recycling infrastructure, WA's take-back scheme for beverage containers and circularity frameworks are drivers. This study concludes that a modulated fee-based product stewardship model focused on product design, along with strategies such as green procurement and landfill management modifications would promote a circular plastic waste economy in WA. This can create markets for secondary recycled plastics, minimize the over-reliance on fossil fuels and prevent plastics from leaking into ecosystems. [ABSTRACT FROM AUTHOR]

The International Panel on Climate Change (IPCC) projects a global temperature rise of 4.3 ± 0.7 °C by 2100 and an extinction of 8.5% in one out of every six species. Australia's aquatic ecosystem is no exception; habitat loss, fragmentation, and loss of biodiversity are being experienced. As the center for Nymphaea species distribution, it presents the culturally, ecologically, and scientifically important genus as the best candidate for habitat suitability assessment in climate change, whose habitat suitability is presumed to decline. The models were run according to the maximum entropy (MaxEnt) method, using one general circulation model (GCM). Projections were made for the current, past, and future in medium (4.5) and high (8.5) representative concentration pathways. Significantly, bio2 and bio15 were highly preferred among the species. Less distribution was noted in West Australia compared to the north, east, and south of the continent, while north of the continent in Western Australia, Northern Territory, and Queensland indicate more habitat contractions compared to the east and southeast of Queensland and New South Wales, although it receives high precipitation. Generally, the species respond variably to both temperature and precipitation variables which is a key species response factor for planners and decision makers in species habitat and biodiversity conservation. [ABSTRACT FROM AUTHOR]

We report the upper and lower bounds for the levelized cost of high-temperature industrial process heat, supplied from electricity generated with solar-photovoltaic (PV) and wind turbines in combination with either thermal or electric battery storage using hourly typical meteorological year (TMY) data, in systems sized to supply between 80% and 100% of continuous thermal demand at a site in the northern part of Western Australia. The system is chosen to supply high-temperature air as the heat transfer media at temperatures of 1000 °C, which is a typical temperature for an alumina or a lime calcination plant. A simplified model of the electrical energy plant has been developed using performance characteristics of real PV and wind systems and TMY data of renewable energy resources. This was used to simulate a large sample of possible system configurations and find the optimal combination of the renewable resources and storage systems, sized to provide renewable shares (RES) of between 80% and 100% of the yearly demand. This allowed the upper and lower bounds to be determined for the cost of heat based on two scenarios in which the excess energy is either dumped (upper bound) or exported to the electricity grid (lower bound) at the average generating cost. The lower bound of the levelized cost of energy ( L C O E L ), which occurs for the system employing thermal storage, was estimated to range from USD 10/GJ to USD 24/GJ for RES from 80 to 100%. The corresponding upper bound (L C O E U ), also estimated for the system using thermal storage, are between USD 16/GJ and USD 31/GJ, for RES between 80% and 100%. The utilization of electric battery storage instead of thermal storage was found to increase the LCOE values by a factor of two to four depending on the share of renewable energy. Compared with current Australian natural gas cost, none of the systems assessed configurations is economical without either a cost for CO2 emissions or a premium for low-carbon products. The estimated cost for CO2 emission that is needed to reach parity with current natural gas prices in Australia is also presented. [ABSTRACT FROM AUTHOR]

Systematic changes, since the beginning of the 20th century, in average and extreme Australian rainfall and temperatures indicate that Southern Australian climate has undergone regime transitions into a drier and warmer state. South-west Western Australia (SWWA) experienced the most dramatic drying trend with average streamflow into Perth dams, in the last decade, just 20% of that before the 1960s and extreme, decile 10, rainfall reduced to near zero. In south-eastern Australia (SEA) systematic decreases in average and extreme cool season rainfall became evident in the late 1990s with a halving of the area experiencing average decile 10 rainfall in the early 21st century compared with that for the 20th century. The shift in annual surface temperatures over SWWA and SEA, and indeed for Australia as a whole, has occurred primarily over the last 20 years with the percentage area experiencing extreme maximum temperatures in decile 10 increasing to an average of more than 45% since the start of the 21st century compared with less than 3% for the 20th century mean. Average maximum temperatures have also increased by circa 1 °C for SWWA and SEA over the last 20 years. The climate changes in rainfall an d temperatures are associated with atmospheric circulation shifts. [ABSTRACT FROM AUTHOR]

Examples of sediment budgets are needed to document the range of budget types and their controls. Sediment budgets for three small agricultural catchments (7.6 to 15.6 km2) in southwestern Australia are dominated by channel and gully erosion, with sheet and rill erosion playing a subordinate role. Erosion was increased by clearing naturally swampy valley floors and hillslopes for agriculture and grazing, and episodic intense rainstorms. The proportion of sediment from channel and gully erosion in the sediment budget appears to be determined by the depth of alluvial fills. Dryland salinization caused by clearing native vegetation has connected hillslopes to channels across narrow floodplains, increasing the Sediment Delivery Ratio (SDR). Yield and SDR are found to be insensitive to major in-catchment changes of vegetation cover after initial clearing, the ratio of sheet and rill erosion/channel and gully erosion, and sediment storage masses. This supports the idea that yield alone is often a poor indicator of the impact of land use and land management change. Riparian vegetation would reduce sediment yield but not phosphorus yield. This study demonstrates the value of mixed methods where field observations and chemical analysis are combined with information from local people. [ABSTRACT FROM AUTHOR]