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Application of organic soil amendments such as manure or compost is commonly listed amongst strategies with potential to sequester carbon in agricultural soils, and Australian farmers are able to earn carbon credits for increasing soil organic carbon (SOC) stocks through the use of organic amendments under the Government’s Emission Reduction Fund. Despite their assumed contribution to enhancing SOC levels and inclusion into climate change mitigation strategies, there has been little qualitative or quantitative assessment of the effects of organic amendments on SOC stocks and dynamics. We evaluated this potential for Queensland (Australia) by collating and analysing information on organic amendments and by modelling soil organic carbon sequestration with the FullCAM model in three different cropping locations. An estimated 2.7 million tonnes dry matter (dm) of organic amendments, containing up to one million tonne (dm) of organic carbon was likely land applied in Queensland in 2015/16. Simulations predicted that, in favourable locations, high annual applications of raw manure and compost (10 t and 15 t ha-1 yr-1 fresh matter, respectively) could result in annual soil organic carbon increases of 0.9% and 0.55%, respectively, averaged over 20 years of continuous sorghum cropping. In less favourable conditions and with less frequent or lower applications, carbon stocks may continue to decline but more slowly than without organic amendments. The paucity of key data for more accurate assessments of carbon sequestration potentials led us to identify research priorities that support development of frameworks for use of organic amendments in agricultural soils for climate, food security and waste management benefits.

International audience

Understanding management-induced C sequestration potential in soils under agriculture, forestry, and other land use systems and their quantification to offset increasing greenhouse gases are of global concern. This chapter reviews management-induced changes in C storage in soils of grazing grassland systems, their impacts on ecosystem functions, and their adaptability and needs of protection across socio-economic and cultural settings. In general, improved management of grassland/pasture such as manuring/slurry application, liming and rotational grazing, and low to medium livestock units could sequester C more than under high intensity grazing conditions. Converting cultivated land to pasture, restoration of degraded land, and maximizing pasture phases in mixed-cropping, pasture with mixed-livestock, integrated forestry-pasturage of livestock (silvopastoral) and crop-forestry-pasturage of livestock (agro-silvopastoral) systems could also maintain and enhance soil organic C density (SOCρ). In areas receiving low precipitation and having high erodibility, grazing exclusion might restore degraded grasslands and increase SOCρ. Yet, optimizing C sequestration rates, sowing of more productive grass varieties, judicial inorganic and organic fertilization, rotational grazing, and other climate-resilient approaches could improve overall farm productivity and profitability and attain sustainability in livestock farming systems. Department of Agriculture, Food and the Marine Environmental Protection Agency

Textiles release fibres to the environment during production, use, and at end-of-life disposal. Approximately two-thirds of all textile items are now synthetic, dominated by petroleum-based organic polymers such as polyester, polyamide and acrylic. Plastic microfibres (

Several tools have been developed to compare the environmental impact of textiles. The most widely used are Higg Materials Sustainability Index (MSI) and MADE-BY Fiber Benchmark. They use data from production to evaluate the environmental impacts of textiles differentiated by fiber type. The use phase is excluded from both tools. This article discusses whether there is evidence that the use of textiles differs systematically between different fiber types and examines the consequences of comparing the environmental impacts of clothing based on differences in production of fibers alone without including differences in their use. The empirical material in this paper is based on analysis of rating tools and a literature review on clothing use. It shows that fiber content contributes to the way consumers take care of and use their clothing. When use is omitted, major environmental problems associated with this stage, such as spread of microplastics, are also excluded. This one-sided focus on material production impacts also excludes the importance of product lifespans, quality, and functionality. The consequence is that short-lived disposable products are equated with durable products. Comparing dissimilar garments will not help consumers to make choices that will reduce the environmental burden of clothing. We need an informed discussion on how to use all materials in the most environmentally sustainable way possible. Norges forskningsråd 244618 Andre: Australian Wool Innovation Ltd. (AWI)

Over the past three decades major changes have occurred in Australia's beef industry, affecting productivity and potentially the amount of resources used and environmental impacts from production. Using a life cycle assessment (LCA) approach with a ‘cradle-to-farm gate’ boundary the changes in greenhouse gas (GHG) emission intensity and key resource use efficiency factors (water use, fossil fuel energy demand and land occupation) are reported for the 30 years from 1981 to 2010, for the Australian beef industry. The analysis showed that over the three decades since 1981 there has been a decrease in GHG emission intensity (excluding land use change emissions) of 14% from 15.3 to 13.1 kg CO2-e/kg liveweight (LW). The improvement was largely due to efficiency gains through heavier slaughter weights, increases in growth rates in grass-fed cattle, improved survival rates and greater numbers of cattle being finished on grain. However, the increase in supplement and grain use on farms, and the increase in feedlot finishing, resulted in a twofold increase in fossil fuel energy demand for beef production over the same time. Fresh water consumption for beef production dropped to almost a third from 1465 L/kg LW in 1981 to 515 L/kg LW in 2010. Three contributing factors for this dramatic reduction in water use were: (i)an increase in the competitive demand for irrigation water, resulting in a transfer away from pasture for cattle to higher value industries such as horticulture, (ii) an initiative to cap free flowing artesian bores in the rangelands, and (iii) an overall decline in water available for agriculture compared to industrial and domestic uses. While there was higher uncertainty relating to estimates of land occupation and emissions from land use (LU) and direct land use change (dLUC), an inventory of land occupation indicated a decline in non-arable land occupation of about 19%, but a sevenfold increase in land occupation for feed production, albeit from a low base in 1981. GHG emissions associated with LU and dLUC for grazing were estimated to have declined by around 42% since 1981, due largely to legislated restrictions on broad-scale deforestation which were introduced progressively between 1996 and 2006. This paper discusses the prospects and challenges for further gains in resource use efficiency and reductions in greenhouse gas intensity for Australian beef production.

The objective of this report is to give an overview of the current state of knowledge concerning microplastic pollution. We focus on microplastic fibres (microfibres) from textiles. The review is a part of a larger work towards better accounting for the use phase in Life Cycle Assessment (LCA) of apparel. Microplastic pollution of marine and freshwater environments has been identified as of concern for only about two decades, but there is now significant evidence of negative impacts on aquatic habitats and marine organisms, while less is known about impact on human health. Estimates suggest that as much as 20% to 35% of all primary source microplastics in the marine environment were fibres from synthetic clothing, and the amount is increasing. Microfibres can enter the environment through primary sources that include fibres shed from synthetic apparel and textiles during use and washing or through secondary sources, predominantly degradation and fragmentation of larger pieces of synthetic textile waste. More than 60% of global textiles are now produced from synthetic fibres. The report reviews current understanding of the level of microplastic, including microfibres from textiles pollution, and its environmental impacts. It summarizes knowledge of which textiles and washing methods appear to contribute more significantly, and discusses challenges of including the microfibre problem in LCA studies of apparel and textiles. It gives a preliminary synthesis of strategies to reduce pollution of microfibres in three main categories: 1. Reducing production and consumption of clothing 2. Improving consumer practices in the use phase of synthetic garments 3. Replace use of synthetic fibres with natural fibres where possible. Formålet med rapporten er å gi en oversikt over dagens kunnskap om forurensning gjennom spredning av mikroplast. Vi fokuserer på mikroplastiske fibre (mikrofiber) fra tekstiler. Rapporten er en del av et større arbeid med å bedre inkluder klærs bruksfase i livssyklusanalyser (LCA). De siste ti årene har oppmerksomheten blitt rettet mot spredning av mikroplast. Det er nå signifikant bevis for negativ påvirkning på liv i vann, mens mindre er kjent om innvirkning på menneskers helse. Estimater antyder at så mye som 20% til 35% av alle primære mikroplastkilder i havmiljøet var fibre fra syntetiske klær, og mengden øker. Mikrofiber spres gjennom primære kilder som inkluderer fiber som løsner fra syntetiske klær og tekstiler under bruk og vask eller gjennom sekundære kilder, hovedsakelig nedbrytning og fragmentering av syntetisk tekstilavfall. Syntetiske fibre utgjør nå mer enn 60% av den globale tekstilproduksjonen. Rapporten evaluerer nåværende forståelse av nivået av mikroplast, inkludert mikrofiber fra tekstilforurensning og dens innvirkning. Den oppsummerer kunnskap omkring hvilke tekstiler og vaskemetoder som bidrar til mest spredning, og drøfter hvordan problemet omkring mikrofiber kan trekkes inn i livssyklusanalyser. Det gir også råd om mulige strategier for å redusere forurensning av mikrofibre i tre kategorier: 1. Redusere produksjon og forbruk av klær 2. Forbedre forbrukspraksis i bruksfasen av syntetiske plagg 3. Erstattet bruk av syntetiske fibre med naturlige fibre.

Pricing greenhouse gas emissions is a burgeoning and possibly lucrative financial means for climate change mitigation. Emissions pricing is being used to fund emissions-abatement technologies and to modify land management to improve carbon sequestration and retention. Here we discuss the principal land-management options under existing and realistic future emissions-price legislation in Australia, and examine them with respect to their anticipated direct and indirect effects on biodiversity. The main ways in which emissions price-driven changes to land management can affect biodiversity are through policies and practices for (1) environmental plantings for carbon sequestration, (2) native regrowth, (3) fire management, (4) forestry, (5) agricultural practices (including cropping and grazing), and (6) feral animal control. While most land-management options available to reduce net greenhouse gas emissions offer clear advantages to increase the viability of native biodiversity, we describe several caveats regarding potentially negative outcomes, and outline components that need to be considered if biodiversity is also to benefit from the new carbon economy. Carbon plantings will only have real biodiversity value if they comprise appropriate native tree species and provide suitable habitats and resources for valued fauna. Such plantings also risk severely altering local hydrology and reducing water availability. Management of regrowth post-agricultural abandonment requires setting appropriate baselines and allowing for thinning in certain circumstances, and improvements to forestry rotation lengths would likely increase carbon-retention capacity and biodiversity value. Prescribed burning to reduce the frequency of high-intensity wildfires in northern Australia is being used as a tool to increase carbon retention. Fire management in southern Australia is not readily amenable for maximising carbon storage potential, but will become increasingly important for biodiversity conservation as the climate warms. Carbon price-based modifications to agriculture that would benefit biodiversity include reductions in tillage frequency and livestock densities, reductions in fertiliser use, and retention and regeneration of native shrubs; however, anticipated shifts to exotic perennial grass species such as buffel grass and kikuyu could have net negative implications for native biodiversity. Finally, it is unlikely that major reductions in greenhouse gas emissions arising from feral animal control are possible, even though reduced densities of feral herbivores will benefit Australian biodiversity greatly.

It is widely recognised that defining trade-offs between greenhouse gas emissions using ‘emission equivalence’ based on global warming potentials (GWPs) referenced to carbon dioxide produces anomalous results when applied to methane. The short atmospheric lifetime of methane, compared to the timescales of CO2 uptake, leads to the greenhouse warming depending strongly on the temporal pattern of emission substitution.We argue that a more appropriate way to consider the relationship between the warming effects of methane and carbon dioxide is to define a ‘mixed metric’ that compares ongoing methane emissions (or reductions) to one-off emissions (or reductions) of carbon dioxide. Quantifying this approach, we propose that a one-off sequestration of 1t of carbon would offset an ongoing methane emission in the range 0.90–1.05kg CH4 per year. We present an example of how our approach would apply to rangeland cattle production, and consider the broader context of mitigation of climate change, noting the reverse trade-off would raise significant challenges in managing the risk of non-compliance.Our analysis is consistent with other approaches to addressing the criticisms of GWP-based emission equivalence, but provides a simpler and more robust approach while still achieving close equivalence of climate mitigation outcomes ranging over decadal to multi-century timescales.

Within the pharmaceutical prescription sector, just like many other markets, maintaining competitive advantage has become increasingly difficult. In the healthcare arena, the period of time that a new chemical entity has on the market before a key competitor emerges has been significantly reduced. If a company has already developed an important market franchise in a given sector or disease area, it is essential that that company understands the potential threats it is likely to face in the future from new product entries and also to appreciate what, if anything, could be done to protect or enhance the product franchise in the light of market developments.

This chapter examines life cycle assessment (LCA) of wool textiles and clothing, focussing on the specific elements of the wool value chain where methodology and data significantly affect quantification of environmental impacts and resource use. Recent methodological developments, particularly for handling co-products from production on sheep farms, and emerging understanding of the benefits of reuse and recycling of wool clothing are discussed in the context of the diversity of production and use of wool. A case study for two merino products demonstrates the relative contributions of life cycle stages and identifies progress and remaining gaps in data and methodology, and future prospects for improved estimates of the environmental performance of wool products using LCA thinking.

Data from 57 permanent monitoring sites are used to document the growth in woody vegetation and estimate the carbon sink in 27Mha of eucalypt woodlands (savannas), contained withii c. 6OMha of grazed woodlands in Queensland (northeast Australia). The study sites are shown to be representative of the environment and structure of the eucalypt woodlands in the defined study area. Mean basal area increment for all live woody plants in 30 long-tenn sites, with an average initial basal area of 11.86 + 1.38 (SE)m2ha-', was 1.06m2ha-' over a mean 14years timeframe. The majority of the measurement period, commencing between 1982 and 1988, was characterized by belowaverage rainfall. The increase in live tree basal area was due primarily to growth of existing trees (3.1Zm2ha-'1 rather than establishment of new plants (0.25m2ha-I) qd was partly offset by death (2.31m2ha-'1. A simple but robust relationship between stand basal area and stand biomass of all woody species was developed for the eucalypt dominant woodlands. Analysis of above-ground carbon stocks in live and standing dead woody plants gave a mean net above-ground annual carbon increment for all 57 sites of 0.53 t C ha-' y-l, similar to values estimated elsewhere in world savannas. Published root: shoot ratios were used to infer C flux in woody mot systems on these sites. This results in an estimated sink in above- and below-ground biomass of 18MtCy-' over the eucalypt woodlands studied, and potentially up to 35MtCy-I if extended to all grazed woodlands in Queensland. It is suggested that introduction of livestock grazing and altered fire regimes have triggered the change in tree-grass dominance in these woodlands. Thus, change in carbon stocks in the grazed woodlands of Queensland is identified as an important component of human-induced greenhouse gas flux in Australia, equivalent in magnitude to c. 25% of the most recently published (1999) total estimated national net emissions. The latter inventory takes into account emissions from land clearing, but does not include the sink identified in the pment study. This sequestration also represents a small but significant contribution to the global terrestrial carbon sink.

Theory suggests that the level of enrichment of18O above source water in plant organic material (Δ) may provide an integrative indicator of control of water loss. However, there are still gaps in our understanding of the processes affecting Δ. One such gap is the observed discrepancy between modeled enrichment of water at the sites of evaporation within the leaf and measured enrichment of the leaf water as a whole (ΔL). Farquhar and Lloyd (1993) suggested that this may be caused by a Péclet effect. It is also unclear whether organic material formed in the leaf reflects enrichment of water at the sites of evaporation within the leaf or ΔL. To investigate this question castor bean (Ricinus communis L.) leaves, still attached to the plant, were sealed into a controlled-environment gas exchange chamber and subjected to a step change in leaf-to-air vapor pressure difference. Sucrose was collected from a cut on the petiole of the leaf in the chamber under equilibrium conditions and every hour for 6 h after the change in leaf-to-air vapor pressure difference. Oxygen isotope composition of sucrose in the phloem sap (Δsuc) reflected modeled ΔL. A model is presented describing Δsuc at isotopic steady state, and accounts for 96% of variation in measured Δsuc. The data strongly support the Péclet effect theory.

Changes in the respiratory rate and the contribution of the cytochrome (Cyt) c oxidase and alternative oxidase (COX and AOX, respectively) were investigated in soybean (Glycine max L. cv Stevens) root seedlings using the 18O-discrimination method. In 4-d-old roots respiration proceeded almost entirely via COX, but by d 17 more than 50% of the flux occurred via AOX. During this period the capacity of COX, the theoretical yield of ATP synthesis, and the root relative growth rate all decreased substantially. In extracts from whole roots of different ages, the ubiquinone pool was maintained at 50% to 60% reduction, whereas pyruvate content fluctuated without a consistent trend. In whole-root immunoblots, AOX protein was largely in the reduced, active form at 7 and 17 d but was partially oxidized at 4 d. In isolated mitochondria, Cyt pathway and succinate dehydrogenase capacities and COX I protein abundance decreased with root age, whereas both AOX capacity and protein abundance remained unchanged. The amount of mitochondrial protein on a dry-mass basis did not vary significantly with root age. It is concluded that decreases in whole-root respiration during growth of soybean seedlings can be largely explained by decreases in maximal rates of electron transport via COX. Flux via AOX is increased so that the ubiquinone pool is maintained in a moderately reduced state.

The study investigated the impact of historical and future climate changes on potential natural vegetation (PNV) types and net primary productivity (NPP) in Australia, using the Comprehensive and Sequential Classification System model and the Miami model coupled with climate of the 1931–70 and 1971–2010 periods and the projected climate in 2050. Twenty-eight vegetation classes were classified based on the key climate indicators with four of them being the major vegetation classes corresponding to Australian rangelands and accounting for 75% of total land area. There was a substantial shift in areas of vegetation classes from the 1931–70 period to the 1971–2010 period due to the increased rainfall over large areas across Australia. The modelling projected a range of changes in vegetation classes for 2050 depending on the climate-change scenario used. Many vegetation classes with more intense land use (e.g. steppe and forest) were projected to decrease in 2050, which may have significant impact on the grazing industry and biodiversity conservation. By 2050, NPP was projected to increase in central and northern Australia and to decrease in southern and eastern coastal areas and was projected to be higher on average than that of the 1931–70 period. The vegetation classes approximately corresponding to Australian rangelands mostly had increased NPP projections compared with the 1931–70 period. Although actual response will partially depend on human management activities, fire and extreme events, the projected increase in average NPP in 2050 indicates that Australian vegetation, particularly the rangeland vegetation, will likely be a net carbon sink rather than a carbon source by 2050, with the exception of a ‘warm-dry’ scenario.

Australian agriculture is faced with the dilemma of increasing food production for a growing domestic and world population while decreasing environmental impacts and supporting the social and economic future of regional communities. The challenge for farmers is compounded by declining rates of productivity growth which have been linked to changes in climate and decreasing investment in agricultural research. The answer must lie in understanding the ecological functionality of landscapes and matching management of agricultural systems and use of natural resources to landscape capacity in a changing climate. A simplified mixed grain and livestock farm case study is used to illustrate the challenges of assessing the potential for shifts in land allocation between commodities to achieve sustainable intensification of nutrition production. This study highlights the risks associated with overly-simplistic solutions and the need for increased investment in research to inform the development of practical strategies for increasing food production in Australian agro-ecosystems while managing the impacts of climate change and addressing climate change mitigation policies.

Soil and land-management interactions in Australian native-forest regrowth remain a major source of uncertainty in the context of the global carbon economy. We sampled soil total organic C (TOC) and soil total N (TN) stocks at 45 sites within the Brigalow ecological community of the Brigalow Belt bioregion, Queensland, Australia. The sites were matched as triplets representing three land uses, specifically: uncleared native brigalow forest (‘Remnant’); grassland pasture (‘Pasture’), derived by clearing native vegetation and maintained as pasture for a minimum of 10 years, and; regrowing native brigalow forest (‘Regrowth’, stand ages ranging from 10 to 58 years) that had developed spontaneously after past vegetation clearing for pasture establishment. Soil TOC fractions and natural abundance of soil C and N isotopes were examined to obtain insight into C and N dynamics. An updated above- and belowground carbon budget for the bioregions was generated. Average soil TOC stocks at 0–0.3-m depth ranged from 19 to 79 Mg ha–1 and soil TN stocks from 1.8 to 7.1 Mg ha–1 (2.5th and 97.5th percentiles, respectively). A trend in stocks was apparent with land use: Remnant > Regrowth ≅ Pasture sites. Soil δ13C ranged from –14 to –27‰, and soil δ15N ranged from 4‰ to 17‰, in general reflecting the difference between Pasture (C4-dominated) land use and N2-fixing (C3-dominated) Remnant and Regrowth. Mid-infrared spectroscopy predicted C fractions as a percentage of soil TOC stock, which ranged from 5% to 60% (particulate), 20–80% (humus) and 9–30% (resistant/inert). The geo-referenced soil and management information we collected is important for the calibration of C models, for the estimation of national C accounts, and to inform policy developments in relation to land-resource management undertaken within the Brigalow Belt bioregions of Australia.

The impact of grazing on soil carbon (C) and nitrogen (N) cycles is complex, and across a large area it can be difficult to uncover the magnitude of the effects. Here, we have linked two common approaches to statistical modelling – regression trees and linear mixed models – in a novel way to explore various aspects of soil C and N dynamics for a large, semiarid bioregion where land use is dominated by grazing. The resulting models, which we term RT-LMM, have the pleasing visual appeal of regression trees, and they account for spatial autocorrelation as per a linear mixed model. Our RT-LMM were developed from explanatory variables that related information on climate, soil and past land management. Response variables of interest were: stocks of soil total organic carbon (TOC), soil total nitrogen (TN), and particulate organic C (POC); the ratio of TOC stock to TN stock; and the relative abundance of stable isotopes δ13C and δ15N in the soil. Each variable was sampled at the depth interval 0–0.3 m. The interactions of land use with, in particular, air temperature and soil phosphorus were strong, but three principal management-related effects emerged: (i) the use of fire to clear native vegetation reduced stocks of TOC and TN, and the TOC : TN ratio, by 25%, 19% and 9%, respectively, suggesting that TOC is more sensitive to fire than TN; (ii) conversion of native vegetation to pasture enriched soil with δ13C by 1.7 ‰; subsequent regrowth of the native vegetation among the pasture restored δ13C to its original level but there was no corresponding change in TOC stock; and, (iii) the time elapsed since clearing reduced POC stocks and the TOC : TN ratio.

Land-change science emphasizes the intimate linkages between the human and environmental components of land management systems. Recent theoretical developments in drylands identify a small set of key principles that can guide the understanding of these linkages. Using these principles, a detailed study of seven major degradation episodes over the past century in Australian grazed rangelands was reanalyzed to show a common set of events: ( i ) good climatic and economic conditions for a period, leading to local and regional social responses of increasing stocking rates, setting the preconditions for rapid environmental collapse, followed by ( ii ) a major drought coupled with a fall in the market making destocking financially unattractive, further exacerbating the pressure on the environment; then ( iii ) permanent or temporary declines in grazing productivity, depending on follow-up seasons coupled again with market and social conditions. The analysis supports recent theoretical developments but shows that the establishment of environmental knowledge that is strictly local may be insufficient on its own for sustainable management. Learning systems based in a wider community are needed that combine local knowledge, formal research, and institutional support. It also illustrates how natural variability in the state of both ecological and social systems can interact to precipitate nonequilibrial change in each other, so that planning cannot be based only on average conditions. Indeed, it is this variability in both environment and social subsystems that hinders the local learning required to prevent collapse.

Effective response by government and individuals to the risk of land degradation requires an understanding of regional climate variations and the impacts of climate and management on condition and productivity of land and vegetation resources. Analysis of past land degradation and climate variability provides some understanding of vulnerability to current and future climate changes and the information needs for more sustainable management. We describe experience in providing climate risk assessment information for managing for the risk of land degradation in north-eastern Australian arid and semi-arid regions used for extensive grazing. However, we note that information based on historical climate variability, which has been relied on in the past, will now also have to factor in the influence of human-induced climate change. Examples illustrate trends in climate for Australia over the past decade and the impacts on indicators of resource condition. The analysis highlights the benefits of insights into past trends and variability in rainfall and other climate variables based on extended historic databases. This understanding in turn supports more reliable regional climate projections and decision support information for governments and land managers to better manage the risk of land degradation now and in the future.

In life cycle assessment studies, greenhouse gas (GHG) emissions from direct land-use change have been estimated to make a significant contribution to the global warming potential of agricultural products. However, these estimates have a high uncertainty due to the complexity of data requirements and difficulty in attribution of land-use change. This paper presents estimates of GHG emissions from direct land-use change from native woodland to grazing land for two beef production regions in eastern Australia, which were the subject of a multi-impact life cycle assessment study for premium beef production. Spatially- and temporally consistent datasets were derived for areas of forest cover and biomass carbon stocks using published remotely sensed tree-cover data and regionally applicable allometric equations consistent with Australia’s national GHG inventory report. Standard life cycle assessment methodology was used to estimate GHG emissions and removals from direct land-use change attributed to beef production. For the northern-central New South Wales region of Australia estimates ranged from a net emission of 0.03 t CO2-e ha–1 year–1 to net removal of 0.12 t CO2-e ha–1 year–1 using low and high scenarios, respectively, for sequestration in regrowing forests. For the same period (1990–2010), the study region in southern-central Queensland was estimated to have net emissions from land-use change in the range of 0.45–0.25 t CO2-e ha–1 year–1. The difference between regions reflects continuation of higher rates of deforestation in Queensland until strict regulation in 2006 whereas native vegetation protection laws were introduced earlier in New South Wales. On the basis of liveweight produced at the farm-gate, emissions from direct land-use change for 1990–2010 were comparable in magnitude to those from other on-farm sources, which were dominated by enteric methane. However, calculation of land-use change impacts for the Queensland region for a period starting 2006, gave a range from net emissions of 0.11 t CO2-e ha–1 year–1 to net removals of 0.07 t CO2-e ha–1 year–1. This study demonstrated a method for deriving spatially- and temporally consistent datasets to improve estimates for direct land-use change impacts in life cycle assessment. It identified areas of uncertainty, including rates of sequestration in woody regrowth and impacts of land-use change on soil carbon stocks in grazed woodlands, but also showed the potential for direct land-use change to represent a net sink for GHG.

Climate change presents a range of challenges for animal agriculture in Australia. Livestock production will be affected by changes in temperature and water availability through impacts on pasture and forage crop quantity and quality, feed-grain production and price, and disease and pest distributions. This paper provides an overview of these impacts and the broader effects on landscape functionality, with a focus on recent research on effects of increasing temperature, changing rainfall patterns, and increased climate variability on animal health, growth, and reproduction, including through heat stress, and potential adaptation strategies. The rate of adoption of adaptation strategies by livestock producers will depend on perceptions of the uncertainty in projected climate and regional-scale impacts and associated risk. However, management changes adopted by farmers in parts of Australia during recent extended drought and associated heatwaves, trends consistent with long-term predicted climate patterns, provide some insights into the capacity for practical adaptation strategies. Animal production systems will also be significantly affected by climate change policy and national targets to address greenhouse gas emissions, since livestock are estimated to contribute ~10% of Australia’s total emissions and 8–11% of global emissions, with additional farm emissions associated with activities such as feed production. More than two-thirds of emissions are attributed to ruminant animals. This paper discusses the challenges and opportunities facing livestock industries in Australia in adapting to and mitigating climate change. It examines the research needed to better define practical options to reduce the emissions intensity of livestock products, enhance adaptation opportunities, and support the continued contribution of animal agriculture to Australia’s economy, environment, and regional communities.

Land-use change, particularly clearing of forests for agriculture, has contributed significantly to the observed rise in atmospheric carbon dioxide concentration. Concern about the impacts on climate has led to efforts to monitor and curtail the rapid increase in concentrations of carbon dioxide and other greenhouse gases in the atmosphere. Internationally, much of the current focus is on the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC). Although electing to not ratify the Protocol, Australia, as a party to the UNFCCC, reports on national greenhouse gas emissions, trends in emissions and abatement measures. In this paper we review the complex accounting rules for human activities affecting greenhouse gas fluxes in the terrestrial biosphere and explore implications and potential opportunities for managing carbon in the savanna ecosystems of northern Australia. Savannas in Australia are managed for grazing as well as for cultural and environmental values against a background of extreme climate variability and disturbance, notably fire. Methane from livestock and non-CO2 emissions from burning are important components of the total greenhouse gas emissions associated with management of savannas. International developments in carbon accounting for the terrestrial biosphere bring a requirement for better attribution of change in carbon stocks and more detailed and spatially explicit data on such characteristics of savanna ecosystems as fire regimes, production and type of fuel for burning, drivers of woody encroachment, rates of woody regrowth, stocking rates and grazing impacts. The benefits of improved biophysical information and of understanding the impacts on ecosystem function of natural factors and management options will extend beyond greenhouse accounting to better land management for multiple objectives.

Concern about the risk of harmful human-induced climate change has resulted in international efforts to reduce greenhouse gas emissions to the atmosphere. We review the international and national context for consideration of greenhouse abatement in native vegetation management and discuss potential options in Queensland. Queensland has large areas of productive or potentially productive land with native woody vegetation cover with approximately 76 million ha with woody cover remaining in 1991. High rates of tree clearing, predominantly to increase pasture productivity, continued throughout the 1990s with an average 345,000 ha/a estimated to have been cleared, including non-remnant (woody regrowth) as well as remnant vegetation. Estimates of greenhouse gas emissions associated with land clearing currently have a high uncertainty but clearing was reported to contribute a significant proportion of Australia's total greenhouse gas emissions from 1990 (21%) to 1999 (13%). In Queensland, greenhouse emissions from land clearing were estimated to have been 54.5 Mt CO2-e in 1999. Management of native vegetation for timber harvesting and the proliferation of woody vegetation (vegetation thickening) in the grazed woodlands also represent large carbon fluxes. Forestry (plantations and native forests) in Queensland was reported to be a 4.4 Mt CO2-e sink in 1999 but there are a lack of comprehensive data on timber harvesting in private hardwood forests. Vegetation thickening is reported for large areas of the c. 60 million ha grazed woodlands in Queensland. The magnitude of the carbon sink in 27 million ha grazed eucalypt woodlands has been estimated to be 66 Mt CO2-e/a but this sink is not currently included in Australia's inventory of anthropogenic greenhouse emissions. Improved understanding of the function and dynamics of natural and managed ecosystems is required to support management of native vegetation to preserve and enhance carbon stocks for greenhouse benefits while meeting objectives of sustainable and productive management and biodiversity protection.

Australia is one of the two largest exporting nations for beef and lamb in the world and the USA is a major export market for both products. To inform the Australian red meat industry regarding the environmental performance of exported food products, this study conducted the first multi-impact analysis of Australian red meat export supply chains including all stages through to warehousing in the USA. A large, integrated dataset based on case study farms and regional survey was used to model beef and lamb from major representative production regions in eastern Australia. Per kilogram of retail-ready red meat, fresh water consumption ranged from 441.7 to 597.6 L across the production systems, stress-weighted water use from 108.5 to 169.4 L H2O-e, fossil energy from 28.1 to 46.6 MJ, crop land occupation from 2.5 to 29.9 m2 and human edible protein conversion efficiency ranged from 7.9 to 0.3, with major differences observed between grass finished and grain finished production. GHG emissions excluding land use and direct land use change ranged from 16.1 to 27.2 kg CO2-e per kilogram, and removals and emissions from land use and direct land use change ranged from −2.4 to 8.7 kg CO2-e per kilogram of retail retail ready meat. Process based life cycle assessment shows that environmental impacts and resource use were highest in the farm and feedlot phase. Transportation contributed ≤5% of greenhouse gas emissions, water and land, confirming that food miles is not a suitable indicator of environmental impacts for red meat transported by ocean shipping. The contribution of international transportation to total energy demand was higher, ranging from 14 to 23%. These beef and lamb supply chains were found to rely on small volumes of water from stressed water catchments, and occupied only small amounts of crop land suited to other food production systems. Production of high quality protein foods for human consumption used only small amounts of protein from human edible grain.

Purpose: Methodology of co-product handling is a critical determinant of calculated resource use and environmental emissions per kilogram (kg) product but has not been examined in detail for different sheep production systems. This paper investigates alternative approaches for handling co-production of wool and live weight (LW, for meat) from dual purpose sheep systems to the farm-gate. Methods: Seven methods were applied; three biophysical allocation (BA) methods based on protein requirements and partitioning of digested protein, protein mass allocation (PMA), economic allocation (EA) and two system expansion (SE) methods. Effects on greenhouse gas (GHG) emissions, fossil energy demand and land occupation (classified according to suitability for arable use) were assessed using four contrasting case study (CS) farm systems. A UK upland farm (CS 1) and a New Zealand hill farm (CS 2) were selected to represent systems focused on lamb and coarse-textured wool for interior textiles. Two Australian Merino sheep farms (CS 3, CS 4) were selected to represent systems focused on medium to superfine garment wool, and lamb. Results and discussion: Total GHG emissions per kilogram total products (i.e. wool + LW) were similar across CS farms. However, results were highly sensitive to the method of co-product handling. GHG emissions based on BA of wool protein to wool resulted in 10–12 kg CO2-e/kg wool (across all CS farms), whereas it increased to 24–38 kg CO2-e/kg wool when BA included a proportion of sheep maintenance requirements. Results for allocation% generated using EA varied widely from 4 % (CS 1) to 52 % (CS 4). SE using beef as a substitution for sheep meat gave the lowest, and often negative, GHG emissions from wool production. Different methods were found to re-order the impacts across the four case studies in some instances. A similar overall pattern was observed for the effects of co-product handling method on other impact categories for three of the four farms. Conclusions: BA based on protein partitioning between sheep wool and LW is recommended for attributional studies with the PMA method being an easily applied proxy for the more detailed BA methods. Sensitivity analysis using SE is recommended to understand the implications of system change. Sensitivity analysis using SE is recommended to investigate implications of choosing alternative products or systems, and to evaluate system change strategies in which case consequential modelling is appropriate. To avoid risks of burden shifting when allocation methods are applied, results should be presented for both wool and LW.

Australia is the largest supplier of fine apparel wool in the world, produced from diverse sheep production systems. To date, broad scale analyses of the environmental credentials of Australian wool have not used detailed farm-scale data, resulting in a knowledge gap regarding the performance of this product. This study is the first multiple impact life cycle assessment (LCA) investigation of three wool types, produced in three geographically defined regions of Australia: the high rainfall zone located in New South Wales (NSW HRZ) producing super-fine Merino wool, the Western Australian wheat-sheep zone (WA WSZ) producing fine Merino wool, and the southern pastoral zone (SA SPZ) of central South Australia, producing medium Merino wool. Inventory data were collected from both case study farms and regional datasets. Life cycle inventory and impact assessment methods were applied to determine resource use (energy and water use, and land occupation) and GHG emissions, including emissions and removal associated with land use (LU) and direct land use change (dLUC). Land occupation was divided into use of arable and non-arable land resources. A comparison of biophysical allocation and system expansion methods for handling co-production of greasy wool and live weight (for meat) was included. Based on the regional analysis results, GHG emissions (excluding LU and dLUC) were 20.1 ± 3.1 (WA WSZ, mean ± 2 S.D) to 21.3 ± 3.4 kg CO 2 -e/kg wool in the NSW HRZ, with no significant difference between regions or wool type. Accounting for LU and dLUC emissions and removals resulted in either very modest increases in emissions (0.3%) or reduced net emissions by 0–11% depending on pasture management and revegetation activities, though a higher degree of uncertainty was observed in these results. Fossil fuel energy demand ranged from 12.5 ± 4.1 in the SA SPZ to 22.5 ± 6.2 MJ/kg wool (WA WSZ) in response to differences in grazing intensity. Fresh water consumption ranged from 204.3 ± 59.1 in the NSW HRZ to 393.7 ± 123.8 L/kg wool in the WA WSZ, with differences primarily relating to climate. Stress-weighted water use ranged from 11.0 ± 3.0 (SA SPZ) to 74.6 ± 119.5 L H 2 O-e/kg wool (NSW HRZ) and followed an opposite trend to water consumption in response to the different levels of water stress across the regions. Non-arable grazing land was found to range from 55% to almost 100% of total land occupation. Different methods for handling co-production of greasy wool and live weight changed estimated total GHG emissions by a factor of three, highlighting the sensitivity to this methodological choice and the significance of meat production in the wool supply chain. The results presented improve the understanding of environmental impacts and resource use in these wool production regions as a basis for more detailed full supply chain analysis.

Measurement of discrimination against 18O during dark respiration in plants is currently accepted as the only reliable method of estimating the partitioning of electrons between the cytochrome and alternative pathways. In this paper, we review the theory of the technique and its application to a gas-phase system. We extend it to include sampling effects and show that the isotope discrimination factor, D, is calculated as –dln(1 + δ)/dlnO*, where δ is isotopic composition of the substrate oxygen and O*=[O2]/[N2] in a closed chamber containing tissue respiring in the dark. It is not necessary to integrate the expression but, if the integrated form is used, the resultant regression should not be constrained through the origin. This is important since any error in D will have significant effects on the estimation of the flux of electrons through the two pathways.