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Supporters of hydrogen energy urge scaling up technology and reducing costs for competitiveness. This paper explores how hydrogen energy technologies (HET) are perceived by Australia's general population and considers the way members of the public imagine their role in the implementation of hydrogen energy now and into the future. The study combines a nationally representative survey (n = 403) and semi-structured interviews (n = 30). Results show age and gender relationships with self-reported hydrogen knowledge. Half of the participants obtained hydrogen information from televised media. Strong support was observed for renewable hydrogen, while coal (26%) and natural gas (41%) versions had less backing. Participants sought more safety-related information (41% expressed concern). Most felt uncertain about influencing hydrogen decisions and did not necessarily recognise they had agency beyond their front fence. Exploring the link between political identity and agency in energy decision-making is needed, with energy democracy a potentially productive direction. • Hydrogen's strongest appeal to Australians is its benefit for climate change mitigation. • Although widely accepted, there is limited knowledge about hydrogen in terms of how it is produced or used. • The more people know about hydrogen, the more willing they are to participate in the decision-making process. [ABSTRACT FROM AUTHOR]

"Rural Australia" has long been a special site of political contestation. Staking the terms of public depictions of "the rural", "the bush", or "country life" is a constitutive thread running through Australian settler colonial identity and a cornerstone of national electoral politics. This paper analyses major News Corporation media outlets' presentation of an evolving political campaign, comparing contesting representations of farming and rural Australia deployed by the Morrison Coalition government and advocacy group Farmers for Climate Action, in the period between the government's re-election in May 2019 and July 2021. The paper steps through the key tactical discursive moves made by these contesting parties. It argues that in their depictions of rural Australia there are two important features that these perspectives share. Both embrace a discourse of increased agricultural productivity inspired by high-tech innovation, and both are silent on the related social and economic transformations that undergird the "crisis" of the rural. Consequently, public political contestation over rural policy unfolds without engaging transforming structural arrangements that fundamentally organise work and life on the land. • Presents comparative depictions of rurality by the Australian prime minister and advocacy group Farmers for Climate Action. • Political contests over the representation of the rural during the time of accelerating climate change are shown to have strong temporal framings. • Both government and Farmers for Climate Action embrace a discourse of increased agricultural productivity inspired by high-tech innovation and both are silent on socio-economic transformations. • Farmers for Climate Action have made significant steps towards normalising the idea that farming and climate activism go hand in hand. [ABSTRACT FROM AUTHOR]

Soil-based carbon farming has been identified in previous research as a win-win for farm productivity and the mitigation of climate change through carbon sequestration. However, it faces numerous barriers to adoption, including low carbon prices, high transaction costs, information barriers and high uncertainty around future outcomes, markets and policy conditions. Collaboration between landholders and other stakeholders has been proposed as a potential means of overcoming some of these barriers, while maximising the benefits of soil-based carbon farming. In this article, we present the results of a two-stage process investigating collaborative soil-based carbon farming in Australia, involving national-scale key informant interviews and a regional-scale Participatory Rural Appraisal. Fifty-three interviews were undertaken with key carbon farming stakeholders, including landholders, landholder groups, carbon service providers, government, researchers and the financial sector. Collaboration was seen to offer the greatest advantages in relation to knowledge-sharing and social support, followed by its potential to increase carbon income through enhanced bargaining power and the optimisation of co-benefits. The advantages of collaboration were less clear in relation to reducing costs or maximising farm productivity and collaboration also presents new challenges around risk and complexity. Under current conditions, informal collaboration models were seen to offer the best balance between the benefits and risks, with existing cooperatives also well-placed to diversify into carbon. Alternative conditions in the future or in other locations would be needed to facilitate models involving joint projects, pooled credits, shared land management and/or the creation of new carbon-specific cooperatives. • Soil-based carbon farming benefits both carbon sequestration and farm productivity. • Advantages of collaboration are greatest for knowledge-sharing and social support. • Collaboration less beneficial in relation to cost-reduction and farm productivity. • Informal models for collaboration preferred by study participants. • Existing agricultural cooperatives are well-placed to diversify into carbon farming. [ABSTRACT FROM AUTHOR]

Wetland area and condition are declining globally despite their importance to climate change mitigation and biodiversity. Introduced ungulate species are contributing to the global decline. Their impacts on wetlands are widespread and varied, however poorly understood. We summarise global impacts of introduced unmanaged and domesticated ungulates on wetlands highlighting potential outcomes of their removal. We place an emphasis on Australia due to the disproportionate impacts of ungulates on wetlands and potential for emerging carbon and biodiversity markets to incentivise private investment in wetland conservation and restoration. Our Systematic Literature Review assessed impacts of cattle, pigs, horses, deer, buffalo, sheep, camels, and other ungulates on wetlands. There were 372 relevant resources from 35 countries, with highest representation from Australia and the United States. The majority related to cattle (29 %) and pigs (19 %). More impacts were reported in freshwater wetlands (51 %) than marine (19 %). A quarter of studies related to riparian habitats. Ungulate impacts varied geographically and among climates. More studies reported soil damage, weed dispersal, decreased vegetation cover, and woody vegetation suppression than neutral or positive changes in these metrics. Decreases in richness and abundance of native flora and fauna were more frequently reported than increases. Of 33 studies reporting wetland carbon impacts, 24 reported increased CO 2 emissions due to loss of soil carbon or vegetation biomass. Ungulate exclusion from wetlands could enhance carbon stocks and biodiversity, however further studies comparing wetland typologies and carbon dynamics are needed to quantify levels of enhancement given differences in ungulate species and environments. • Wetlands are declining despite their importance for climate change and biodiversity. • Impacts of feral and domesticated ungulates on wetlands vary by ecology, region, climate, and wetland type. • Ungulates damage soils and reduce ground cover, which may increase carbon emissions. • Reported ungulate impacts on flora and fauna are most often negative, but effects depend on taxa and region. • Control of ungulates in wetlands may support wetland conservation and restoration. [ABSTRACT FROM AUTHOR]

The soil security concept has been put forward to maintain and improve soil resources inter alia to provide food, clean water, climate change mitigation and adaptation, and to protect ecosystems. A provisional framework suggested indicators for the soil security dimensions, and a methodology to achieve a quantification. In this study, we illustrate the framework for the function soil carbon storage and the two dimensions of soil capacity and soil condition. The methodology consists of (i) the selection and quantification of a small set of soil indicators for capacity and condition, (ii) the transformation of indicator values to unitless utility values via expert-generated utility graphs, and (iii) a two-level aggregation of the utility values by soil profile and by dimension. For capacity, we used a set of three indicators: total organic and inorganic carbon content and mineral associated organic carbon in the fine fraction (MAOC) estimated via their reference value using existing maps of pedogenons and current landuse to identify areas of remnant genosoils (total organic and inorganic carbon) and the 90th percentile for MAOC. For condition we used the same set of indicators, but this time using the estimated current value and comparing with their reference-state values (calculated for capacity). The methodology was applied to the whole of Australia at a spatial resolution of 90 m × 90 m. The results show that the unitless indicator values supporting the function varied greatly in Australia. Aggregation of the indicators into the two dimensions of capacity and condition revealed that most of Australia has a relatively low capacity to support the function, but that most soils are in a generally good condition relative to that capacity, with some exceptions in agricultural areas, although more sampling of the remnant genosoils is required for corroboration and improvement. The maps of capacity and condition may serve as a basis to estimate a spatially-explicit local index of Australia's soil resilience to the threat of decarbonization. • Methodology based on the soil security assessment framework. • Quantification of the capacity and condition of the soil to store carbon. • Spatial estimation of the utility to support carbon storage for three indicators. • Australia has low capacity, but overall good condition to store carbon. • Intensive up-to-date sampling is required to corroborate the results. [ABSTRACT FROM AUTHOR]

We modelled and mapped the distribution of three principal soil organic carbon (SOC) fractions across New South Wales and gained insights into the factors controlling their distribution. Carbon fractions are important for modelling soil carbon dynamics for carbon accounting, and as a potential indicator of soil quality. We considered particulate organic carbon (POC), humic organic carbon (HOC) and resistant organic carbon (ROC), which represent fractions of increasing bio-chemical stability. A dataset of 427 NSW profiles with mid-infrared (MIR) derived carbon fractions and a set of 16 predictor variables were applied. Random Forest and multiple linear regression techniques were applied, for depth intervals to 30 cm. The derived models and maps were of moderate strength, with validation results revealing Lin's concordance values for the 0–30 cm depth interval of 0.79 for total SOC stocks and 0.60 to 0.74 for the fraction stocks. Maps of mean stocks, and upper and lower 95% prediction intervals are presented. Absolute stocks (in Mg ha−1) of each fraction have a strong linear relationship with total SOC and are controlled by similar environmental and land management factors, normally increasing in a systematic way with increasingly moist climate (considering rainfall and temperatures), increasing mafic lithology (associated with more fertile, clay rich soils) and less disturbed land uses with higher vegetation cover. The environmental factors influencing the relative proportions of each fraction (% of total SOC) are more complex, but climate and lithology appear to be dominant, in addition to depth in profile. An SOC vulnerability index is mapped over the State, identifying areas where the stored carbon is most vulnerable to land management or environmental change. Our findings add to the understanding of factors driving the distribution of soil carbon and its fractions, which may ultimately contribute to more effective climate change mitigation programs. Unlabelled Image • Digital soil maps of three SOC fractions (at 100 m resolution) prepared for NSW • Absolute stocks of SOC fractions have strong linear relationship with total SOC. • All stocks increase with moister climate, more mafic soil and higher vegetation cover. • Relative proportions (% of total SOC) influenced by climate, lithology and depth • SOC vulnerability index mapped over NSW [ABSTRACT FROM AUTHOR]

Climate change poses both immediate and anticipated challenges. With growing awareness of climate change and much of their life courses ahead, young people are distinctively positioned to experience anticipated challenges. This article reports the findings of a survey conducted among 1943 young people (15 – 19 years) living across Australia. The survey examined respondents' knowledge, perceptions, and emotional experiences of climate change, and how these factors influence their views and decision-making regarding the future. Quantitative analysis indicates higher concern and impactful feelings about climate change, as well as personal proximity to climate change and taking climate action, were the most important predictors for how respondents made choices about their lives, and their outlook on the future. Through, qualitative analysis of open-ended five key themes emerged in respondents' perceptions of climate futures: preparing for uncertainty, dependent on the powerful, disconnected from climate change, running out of time, and grieving a dead future. Overall, findings suggest climate change is a significant influence on how young people think about and make choices about their lives and the future. The present impacts of anticipated climate change in the lives of young people need greater recognition in research, policy and public discussion about climate change. • Reports the findings of a national survey of 1943 young people aged 15 – 19 years living across Australia. • Examined knowledge, perceptions, and emotional experiences of climate change, and the future. • Climate change is a significant influence on how young people think and make choices about their lives and futures. • The impacts of anticipated climate change in young peoples' lives needs greater recognition in research, policy and public discussion. [ABSTRACT FROM AUTHOR]

• Results of a large national Australian survey of young people (15–19 years) • High concern, worry, powerlessness, and frustration about climate change. • Respondents most commonly talked to friends about climate change feelings. • Feeling listened to predicted talking about climate change feelings. • Differences in emotions when talking to different generations were evident. • Young people need respect, opportunities to act, and shared understanding. The emotional significance of climate change for young people is becoming recognised. However, their experiences of talking about these feelings are not well understood, despite being acknowledged as an important avenue for support and social change. This article reports on a survey of 1,943 young people aged 15–19 years living in Australia. The survey examined their level of concern about climate change, the feelings they associate with climate change, whom they talk to about these feelings, under what conditions, and with what effects. Respondents reported a high level of concern about climate change, most associated with feelings of worry, powerlessness, and frustration. Friends were most trusted to share these feelings with, followed by parents/guardians and then teachers. The most important predictor of young people talking about their climate feelings was whether they felt listened to. Respondents were more likely to feel comfortable having climate conversations with younger or same-aged people and associated these conversations with hope. In contrast, climate conversations with older people were most often associated with betrayal, uncertainty, and worry. Through open-ended responses, the young people surveyed called for further respect and consideration of their views, opportunities to drive action and lead climate conversations, and a need for shared understanding of the issues at stake. Our findings highlight opportunities for those who care about and interact with young people to help them come to terms with the challenges of living in a changing climate through listening and creating safe spaces for what can be difficult discussions. [ABSTRACT FROM AUTHOR]

Whilst carbon capture and storage (CCS) has been promoted as a direct countermeasure against global warming, there remains much debate about what its final role as a climate change mitigation strategy will be. One key criticism directed towards CCS has been its inability to gain public support. This study compares public attitudes to the range of low carbon energy sources and technologies across Australia and China, and is the first study to compare primary data across these two countries on this topic. An online survey encompassing a broad set of questions was used to identify the factors that are associated with support for CCS compared to other energy technologies. Data were collected from a nationally representative Australian sample (n = 2383) and from Chinese urban residents across six regions (n = 1266). The survey confirmed low levels of knowledge and support for CCS in both countries. However, male respondents, those who perceived themselves to have higher knowledge of CCS, and those who valued economic outcomes over environmental protection were more likely to support CCS - as long as the risks were not perceived to outweigh the benefits. The results found that for Australians who believed in human-induced climate change they were likely to be unsupportive of CCS. This opposition appears to be linked to no tolerance for extending fossil fuels as in our factor analysis CCS was aligned to fossil fuels in Australia. In both countries, support for renewable energy technologies remains strong. Given the International Energy Agency's future energy demand projections, combined with slow progress towards meeting the Paris Climate Agreement, the lack of knowledge and support for CCS is concerning. While there have been some technological advances, without parallel improvements in public acceptance of CCS, it will be difficult to see any commercial projects going forward in the near future. Although, the Chinese government's success in educating on climate science, as evidenced in these results, suggests that they may be more effective at informing the public of the benefits of CCS and take the lead on its deployment for climate change mitigation. Based on the latest climate models, it is almost crunch time for governments to decide if CCS has a role to play as part of an energy transition to a low carbon future or perhaps it may be time to turn their focus to climate adaptation. [ABSTRACT FROM AUTHOR]

Abstract Understanding carbon emissions embodied in trade is an important prerequisite for the effective formulation of climate mitigation policies. Based on input–output analysis and panel regression models, this study proposes a multi-step forecasting procedure to simulate carbon emissions embodied in bilateral trade. We calculate carbon emissions embodied in the trade between China and Australia during 2000–2014 and forecast the same for the period 2015–2022 under four different development scenarios. The results show that, during 2000–2014, net carbon outflow from China to Australia increased from 2.2 to 15.5 Mt CO 2 , concentrated in textile and heavy manufacturing sectors. The simulation results show that, the forecasts of "R&D focus" and "GDP focus" scenarios constitute the lower and upper bounds of embodied emissions, and the latter is more than two times of the former in 2022 both for embodied emissions in Australia's exports and China's exports. Finally, conclusions are drawn and policy implications are discussed. Highlights • A multi-step forecasting procedure of carbon emissions embodied in trade is proposed. • Carbon emissions embodied in China–Australia trade during 2000–2014 are analyzed. • A scenario analysis is conducted for emissions embodied in China–Australia trade. [ABSTRACT FROM AUTHOR]

Abstract The study aimed to identify diurnal indoor temperature patterns and quantify the impact of outdoor on indoor temperature as well as of other modifying factors. Indoor and outdoor temperatures of 77 houses in Brisbane, Australia were monitored with temperature sensors for one year (May 2017–2018). A linear mixed effect model predicted that on average, a 1°C increase in outdoor temperature resulted in a 0.41°C increase in indoor temperature during both the cool and warm seasons. The age of the house, building material, roof material and insulation had a moderate influence on indoor temperature. Queenslander houses (a stand-alone timber structure mounted on stumps with an extensive veranda) were, in general, cooler (0.5°C cooler in winter) and reactive (meaning, having a strong association with the outdoor temperature), while slab-on-ground houses were, in general, warmer (0.3°C) and stable (meaning, having less association with the outdoor temperature). From the indoor temperature patterns identified for the heated and cooled houses it was concluded that in this climate, heating and cooling is seldom done for 24 h. This quantitative information is crucial for understanding the influence of temperature on human health and household energy consumption at the time when climate change mitigation approaches are being discussed. [ABSTRACT FROM AUTHOR]

• Transformative change is needed in landscape practice to enhance its climate agency. • Little is known about the barriers and facilitators of designing for climate change. • Insights from Australian practitioners highlight lack of agency as a key barrier. • Transformation in structures and systems of decision-making processes is needed. • Improved advocacy, engaging with policy and collaboration advance designers' agency. The way we plan and design our landscapes, infrastructure, and cities has to transform if we want to meet the needs of our society and address climate change without breaching the earth's ecological boundaries. Landscape architects are known as environmental stewards. They are trained to create a balance between the built and natural environments. However, landscape architects' agency to lead climate change actions is restricted. Little is known about the barriers to addressing climate change in landscape architectural practice, and the levers to increase landscape architects' agency in climate change leadership. This paper addresses this gap through an in-depth empirical analysis of barriers and facilitators of climate change action from the perspective of landscape architecture professionals. In-depth interviews were conducted with 24 practitioners from Australia. The results show that those interviewed perceived the profession had limited agency and influence in leading climate decisions. Other barriers exist and are grouped against the three spheres of transformation: 1) design implementation barriers influencing the built outcomes (practical); 2) structures and systems barriers influencing the design decision-making processes (political); and 3) socio-cultural barriers including values, ideologies, and beliefs (personal). The most restricting barriers that emerged were those related to limited project budget and timeframes, informational and technological aspects (access to reliable data, tools, and skillsets), as well as those related to political systems and structures in place (regulations, and design standards). Key facilitators to address existing barriers are identified, including creating awareness through practice and advocacy, active involvement of professionals in all life stages of projects, especially in planning and policy creation, and closer collaborations with other built environment sectors beyond sub-consultancy. The findings can pave the way towards increased agency and impact of the profession to bring climate change agendas to the forefront of landscape design practice. [ABSTRACT FROM AUTHOR]

• Estimates of the time of emergence of climate change (ToE) for Australian rivers. • Stochastic data generation helps to better define baseline variability. • Uncertainty in ToE represented by 37 CMIP6 projections and 3 emissions scenarios. • ToE in river flows can precede ToE in precipitation by up to 50 years. • ToE substantially delayed or avoided in a low emissions pathway (SSP1-2.6). Climate change impacts on river flows are leading to substantial changes in water availability for human and natural systems. The significance of these impacts largely depends on the degree of change relative to natural variability. The 'Time of Emergence' (ToE) is the point in time (past or future) when the signal of climate change emerges from the noise of background variability. The ToE has been assessed for some climate variables but rarely streamflows. Here we investigate ToE of changes in streamflow across Australia for various characteristic periods relevant to different water management objectives. We assess the uncertainty in ToE estimates from different emissions pathways and a large ensemble of CMIP6 climate model projections. ToE is likely to occur earlier in hydrologic systems subject to low natural variability than those subject to high variability, and to systems that are vulnerable to failure over longer rather than shorter periods. There are clear regional differences in the patterns of ToE, with changes first emerging in south-west regions of Australia, followed by the south-east, then east and north. We estimate that ToE has already occurred in over 10% of sampled rivers for longer characteristic periods, primarily in south-west Australia. Importantly for planning, the results show that ToE in flows precedes ToE in precipitation by up to 50 years due to compounding effects of changes in annual precipitation, precipitation seasonality, and increasing temperatures. The number of catchments projected to have reached ToE by 2080 is heavily influenced by the trajectory of future emissions. A low emissions pathway generally consistent with aspirational goals of the Paris Climate Agreement (SSP1-2.6) substantially delays the emergence of significant hydrological change by up to 50 years, or negates emergence entirely by 2080, depending on location. Our methods can be applied to catchments globally, and our findings have implications for the prioritisation of climate adaptation efforts across different river systems and the urgency of continued action on climate change mitigation. [ABSTRACT FROM AUTHOR]

Carbon farming policies aim to contribute to climate change mitigation, but their success strongly depends on whether landholders actually adopt desired practices or participate in offered programs. The Australian Government’s Carbon Farming Initiative and Emissions Reduction Fund policies were designed to incentivise the adoption of carbon farming practices. Although these policies have been active since December 2011, farmer engagement has been limited, and net emissions reductions low as a result. We surveyed broad-acre farmers in the Western Australian wheatbelt to explore their drivers and barriers to adopting carbon farming practices and participating in carbon farming policy programs. Drivers of adoption included knowledge and perception of co-benefits (for yield, productivity, and the environment), knowing another adopter, and believing that changes to farm management are an appropriate method to reduce Australia’s greenhouse gas emissions. Barriers to adoption included lack of information, uncertainty and costs. The key barrier to participation was policy and political uncertainty. The determinants of adoption and participation that we identify in our study offer important insights into how to best ensure the success of Australia’s land sector-based climate change policies. We conclude that, to increase landholder engagement, the co-benefits and climate change benefits of carbon farming practices must be actively promoted, and additional information is needed about the costs associated with adoption. Information diffusion is best achieved if it actively leverages landholder social networks. Finally, our results indicate that landholder buy-in to carbon farming could be greatly enhanced by achieving more continuity in Australian climate change policies and politics. [ABSTRACT FROM AUTHOR]

Background In Australia, co-benefits have rarely entered policy discourse and have so far failed to gain traction in climate change-related policy debates. This is partly due to the dominant perception about the difficulties associated with identifying, quantifying and incorporating co-benefits into decision-making frameworks. There is also limited understanding on the part of policy-makers about the profound policy implications of a ‘co-benefits approach’ as a paradigm that can address multiple policy goals, including addressing climate change impacts, achieving sustainable development, and enhancing health, wellbeing and liveability. Objectives Our paper addresses this gap by contributing to current understandings of the ‘co-benefits approach’ as a means of integrating climate concerns into local planning and development control in general. At a more specific level, the paper provides an insight into the Australian local government policy context to illustrate how to plan, generate and purposively promote co-benefits in planning urban built environments. Methods A desktop review of NSW councils’ web sites and their climate change-related policies was undertaken. A comprehensive online survey was subsequently conducted to investigate the extent to which councils have adopted a ‘co-benefits approach’ in their low carbon policies. Results Major barriers to integrating co-benefits in the policy process were identified in this research. They include: (i) local government's current practice of single-sectoral policy development; (ii) absence of an integrated and co-ordinated ‘whole-of-government approach’ to address climate change impact; (iii) over-reliance on quantitative decision-support frameworks; and (iv) over-emphasis on short term and readily quantifiable monetary consideration of benefits. Conclusion Local government's over-emphasis on readily quantifiable ‘monetary considerations’ in targeting benefits from climate change policies excludes a wide range of environmental, social and health benefits from incorporation in policy. This limits the achievement of optimal policy outcomes across multiple sectors using a co-benefits approach. [ABSTRACT FROM AUTHOR]

• Forests can shift to alternate states where regeneration fails post-disturbance. • Empirical experiments can help to quantify alternate states in forests. • Acacia woodland replaces ash-type eucalypt forest where regeneration fails. • Transition to alternate states can compromise the functional integrity of forests. • Management changes and intervention must mitigate the risk of regeneration failure. Under the current trajectory of accelerated climatic and environmental change, many forests are at risk of regeneration failure and subsequent transition to alternate stable states including non-forests or grassland. These regimes shifts can have severe ecological impacts and compromise carbon stores, undermine climate change mitigation, and create conditions incompatible with the survival of biodiversity. However, detailed empirical-based understanding of the alternative states associated with disturbance regime shifts is limited. Here, using a manipulative experiment, and controlling for seed application, we document temporal patterns of vegetation structure and composition associated with regeneration failure after clearcut logging in the ash-type eucalypt forests in south-eastern Australia. Our findings clearly demonstrate that in the absence of direct seed input, frequent stand-replacing disturbance can result in regeneration failure in these forests leading to them being replaced by low species diversity Acacia woodland. These insights can be extrapolated to scenarios of post-fire regeneration failure, where frequent fire precludes the development of adequate seed-stores (<21 years). Such shifts to alternative stable states can have severe ecological implications which require management intervention to circumvent and conserve the functional integrity of these forests. Our case study demonstrates the value of manipulative empirical experiments in quantifying the potential aftermath of forest regeneration failure. Such experiments may be useful to support theories and models in quantifying the ecological implications of regeneration failure, and to guide the application of management interventions for restoration where empirical-based knowledge of these states is limited. [ABSTRACT FROM AUTHOR]

Farming systems face dual pressures of reducing greenhouse gas (GHG) emissions to mitigate climate change and safeguarding food security to adapt to climate change. Building soil organic carbon (SOC) is proposed as a key strategy for climate change mitigation and adaptation. However, practices that increase SOC may also increase nitrous oxide (N 2 O) emissions, and impact crop yields and on-farm income. A comprehensive assessment of the effects of different management practices on trade-offs between GHG emissions and agricultural systems profitability under climate change is needed. We aimed to: (1) analyze the long-term trends of SOC and N 2 O emissions, and ascertain whether the croplands of the study region are net GHG sources or sinks under climate change; (2) quantify the GHG abatement on a gross margin basis; (3) identify effective management practices that could achieve a win-win strategy; and (4) investigate sources of uncertainty in estimates of GHG emissions and gross margins under climate change. APSIM was used to simulate the effects of three crop residue retention rates (10%, 50% and 100%), and six representative crop rotations (wheat-canola, wheat-field pea-wheat-canola, wheat-field pea-wheat-oats, wheat-wheat-barley, wheat-wheat-canola, and wheat-wheat-oats) under two Shared Socio-economic Pathways scenarios (SSP245 and SSP585) using climate projections from 27 GCMs. GHG emissions and gross margins from 1961 to 2092 were assessed across 204 study sites in southeastern Australia. Our results showed that residue retention can turn the soil from a carbon source (10% retention, 304–450 kg CO 2 -eq ha−1 yr−1) to a carbon sink (100% retention, −269 ∼ −57 kg CO 2 -eq ha−1 yr−1), and the potential of carbon sequestration was partly offset by concomitantly increased N 2 O emissions. The wheat-wheat-canola rotation with full residue retention was shown to be a win-win solution with both large potential of GHG abatement and high gross margin compared with other rotations. Spatial analysis showed that the southeastern part of the study region, with higher rainfall, had higher gross margins, while the drier northwestern part had greater GHG emission reduction potentials. Although climate change led to increased GHG emissions and decreased yields for some crops, these adverse effects were overweighed by the higher SOC and yield advantages from full residue retention. This study emphasizes the significant potential for agronomic management to maximize gross margin and reduce GHG emissions under climate change in southeast Australia. Results from this study could be used by farmers and policymakers to mitigate climate change without compromising agroecosystem profitability. [Display omitted] • APSIM was used to simulate the effects of residue retention and crop rotation on GHG emissions and gross margins. • Retaining all crop residues could turn the soil from a carbon source to a carbon sink, and benefit gross margins. • Enhancement of residue retention on GHG abatement overweighed adverse effects of climate change under SSP245 and SSP585. • The wheat-wheat-canola rotation was the most beneficial in terms of GHG mitigation and profitability compared with others. [ABSTRACT FROM AUTHOR]

Sequestering atmospheric carbon in soils is considered a key climate change mitigation strategy and including cover crops into cropping systems is commonly promoted as a management change that can increase soil organic carbon (SOC). Projecting SOC changes under climate change when cover crops are integrated into a cropping system is important because climate is a key driver of SOC dynamics and projected changes in climate are uncertain. Further, projecting SOC changes can provide landholders with information on the risk associated with the use of cover crops to generate carbon credits considering the inherent uncertainty in SOC changes under a changing climate. The Agricultural Production SIMulator was used to simulate SOC and yields of a typical crop rotation, with and without a cow pea cover crop, at 204 sites in the Riverina region of Southern Australia. Sowing cover crops reduced crop yields and increased SOC relative to the crop rotation without cover crops. GHG emissions associated with indirect land use change due to reduced crop yields and N 2 O emissions from the cover crop meant that sowing cover crops was unlikely to provide climate change mitigation. The number of carbon credits generated by participating in the soil carbon method of the Australian government's emissions reduction program varied greatly across the region with some sites not generating any credits. The implications of these results are discussed with respect to climate change mitigation and the risk of entering a SOC trading program when costs of compliance are high and the ability to generate carbon credits is uncertain. • Cover crops replace traditional fallow periods in dryland cropping systems. • Cowpea cover crops reduced the yield of cereal, oilseed and legume crops. • Total GHG emissions were generally greater than SOC sequestration. • Replacing fallows with cowpeas unlikely to reduce GHG emissions. • Climate change mitigation was variable across the region of interest. [ABSTRACT FROM AUTHOR]

• Biomass, litterfall, decomposition and soil carbon data were collated. • Data was sourced from decades of research in plantations and farm forestry. • These data informed the model predicting carbon in tree plantings across Australia. • Biomass, litterfall and decomposition data first constrained the model. • The model was then efficiently calibrated for prediction of litter and soil carbon. Understanding carbon sequestration from tree planting and management activities is important for contributing to the mitigation of climate change. Although rates of growth and resulting sequestration of carbon in live above-ground biomass are relatively well understood in various woody plantings and commercial plantations in Australia, less is known about associated changes in live below-ground biomass, and the turnover and decomposition of biomass, and hence, resulting changes in carbon stocks of litter and soil. Our objective was to develop a modelling approach for predicting these processes and the resulting changes in litter and soil carbon following the establishment and/or management of tree plantings (EMTP) to facilitate their inclusion in carbon abatement projects. We reviewed and collated data on allocation of biomass, litterfall, litter decomposition, litter/harvest residue mass and soil organic carbon (N = 5,655 estimates). Data were sourced from existing field studies of woody plantings (mixed-species environmental and mallee eucalypt), commercial plantations (hardwood and softwood) and in some cases, eucalypt-dominant native forests. After constraining a carbon accounting model to observed measures of growth, allocation of biomass, and rates of litterfall and litter decomposition, the model was calibrated to maximise the efficiency of prediction of litter and soil pools. Although large uncertainties in 'observed' results meant that precision of prediction in any given data source was relatively poor, model predictions had negligible overall bias. The size and diversity of datasets applied in the process of calibration improved overall confidence in model predictions of litter and soil carbon pools. The calibrated model will therefore be a useful tool for informing land managers and policy makers seeking to understand on-site dynamics of all carbon pools, and hence, the total contribution to carbon abatement of different EMTP projects in Australia. [ABSTRACT FROM AUTHOR]

This paper presents an integrated analysis of the costs and benefits of carefully constructed scenarios for the electrification of transport in Australia. Scenarios were constructed to responsively meet increased electricity demand, whilst maximising emission reduction, household finances and public health benefits. The scenarios bundle several technologies, including charging infrastructure, electric vehicles, home battery systems, and renewable energy. The fastest, mission-style, adoption scenario can reduce emissions by 9% of the 2030 carbon budget and reduce the loss of life by 24,000 by 2042. In all scenarios, government expenditure is dwarfed by the estimated public benefits, and households are nearly always better off in the medium to long term. Demonstrating the feasibility and advantages of surface transportation electrification in Australia, which presents cross-sections of rural and urban infrastructure, traffic and a large, socially and politically diverse population, provides broadly applicable evidence of the feasibility of electrification in other jurisdictions. [ABSTRACT FROM AUTHOR]

The prediction of future drought is an effective mitigation tool for assessing adverse consequences of drought events on vital water resources, agriculture, ecosystems and hydrology. Data-driven model predictions using machine learning algorithms are promising tenets for these purposes as they require less developmental time, minimal inputs and are relatively less complex than the dynamic or physical model. This paper authenticates a computationally simple, fast and efficient non-linear algorithm known as extreme learning machine (ELM) for the prediction of Effective Drought Index (EDI) in eastern Australia using input data trained from 1957–2008 and the monthly EDI predicted over the period 2009–2011. The predictive variables for the ELM model were the rainfall and mean, minimum and maximum air temperatures, supplemented by the large-scale climate mode indices of interest as regression covariates, namely the Southern Oscillation Index, Pacific Decadal Oscillation, Southern Annular Mode and the Indian Ocean Dipole moment. To demonstrate the effectiveness of the proposed data-driven model a performance comparison in terms of the prediction capabilities and learning speeds was conducted between the proposed ELM algorithm and the conventional artificial neural network (ANN) algorithm trained with Levenberg–Marquardt back propagation. The prediction metrics certified an excellent performance of the ELM over the ANN model for the overall test sites, thus yielding Mean Absolute Errors, Root-Mean Square Errors, Coefficients of Determination and Willmott's Indices of Agreement of 0.277, 0.008, 0.892 and 0.93 (for ELM) and 0.602, 0.172, 0.578 and 0.92 (for ANN) models. Moreover, the ELM model was executed with learning speed 32 times faster and training speed 6.1 times faster than the ANN model. An improvement in the prediction capability of the drought duration and severity by the ELM model was achieved. Based on these results we aver that out of the two machine learning algorithms tested, the ELM was the more expeditious tool for prediction of drought and its related properties. [ABSTRACT FROM AUTHOR]

Cities must transform in order to address the challenge of climate change and to achieve societal ambitions such as the sustainable development goals. However, a key impediment to achieving transformation is underdeveloped understandings of how key actors and sectors within the built environment work together to achieve goals. This paper addresses these gaps by developing and visually presenting a process map to describe: the key processes involved in producing the built environment across its life stages; key sectors of the built environment, their key actors, and the activities coordinated between them. The process map was peer reviewed by an expert reference group of built environment professionals active in Australia and the UK. The motivation for developing this process map is to facilitate future research to identify and expedite opportunities for coordinated action to address significant societal challenges such as climate change action, and the sustainable development goals – which require transformative action in cities. • Cities must transform to address climate change • We develop a process map to describe the production of the built environment • Process map describes fundamental activities for producing the built environment • Process map spans built environment life stages; identifying activities and interactions of key sectors and actors • Can be applied to inform transformative action targeted at challenges such as climate change [ABSTRACT FROM AUTHOR]

Agricultural vulnerability assessment is a comprehensive and powerful analytical tool to locate hotspots with states of susceptibility to harm and powerlessness of agricultural system. It plays an important role in guiding policy makers to plan and implement adaptation practices to mitigate potential climate risks to crop. However, due to the diversity in the methodology of vulnerability assessment, there are still knowledge gaps in assessing and comparing crop vulnerability to climate in different regions of the world, including Australia. Our main objectives were to: (1) present a vulnerability analytical method for wheat yield, which can be applied to different areas where long-term crop yield and climate data are available. (2) quantify temporal changes of the vulnerability of wheat yield to historical climate. (3) identify the most vulnerable region in study area to provide guidance for climate mitigation. Our study developed an indicator-based method using exposure, sensitivity, and adaptive capacity to assess the vulnerability of crop yield. We used the long-term recorded wheat yield data, combining with comprehensive exposure index to assess climate vulnerability of historical yield with a case study area of south-eastern Australia's wheat belt. The results showed that from the 1930s to the 1990s, both climate exposure and sensitivity had large inter-annual variations with no significant trends detected. However, adaptive capacity increased by 34% from 1930s to 1950s, 54% from 1950s to 1970s, and 54% from 1970s to 1990s. By contrast, climate vulnerability across the wheat belt decreased by 13% from 1930s to 1950s, 15% from 1950s to 1970s, and 33% from 1970s to 1990s. This is mainly due to increased adaptive capacity with the improvement of agronomic management practices, technological and socio-economic progress. We identified the areas with the highest vulnerability were in the northwestern parts of wheat belt while the least vulnerable areas located in the southeast. We expect that these identified vulnerable hotspots can be used by different landholders to allocate natural resources and policymakers to plan the priority mitigation to adapt to climate change in the local scale. Moreover, the method of vulnerability assessment used in this study can be applied to other regions around the world where long-term crop yield and climate data are available. [Display omitted] • A modified indicator-based method was developed to assess wheat yield vulnerability. • Machine learning was used to obtain weights of climate indices when calculating exposure. • Historical vulnerability of wheat yield decreased as the improved adaptive capacity. • The most vulnerable areas were the north-western parts of the wheat belt. • This vulnerability assessment method can be applied to other regions with long-term data of crop yield and climate. [ABSTRACT FROM AUTHOR]

• We model operational and embodied GHG emissions for Australia's built environment. • The scope includes residential and commercial buildings. • A high ambition scenario delivers a 94% reduction in emissions compared to BAU. • Includes renewables, electrification, efficiency and material replacement. • Novel pathways analysis highlights options for net zero and net negative emissions. Achieving net zero operational and embodied greenhouse gas (GHG) emissions in the built environment is recognised in Australia and globally as a key strategy to address climate change and achieve the United Nations Sustainable Development Goals (SDGs). However, gaps in knowledge remain regarding potential national pathways to achieve this outcome in Australia. This study further extends and applies a national-scale integrated macroeconomic simulation model to explore coherent pathways to net zero emissions in the built environment sector by 2050. The scope of the study includes residential and commercial buildings and both operational and embodied emissions. It applies scenario analysis incorporating different levels of climate ambition, including a shift to renewable energy, electrifying buildings, improving energy efficiency and replacing carbon-intensive materials. We find that a high ambition scenario (Scenario 2) delivers a 94% reduction in GHG emissions by 2050 when compared against business-as-usual, placing a net-zero target within reach. Improvements on Australia's SDGs performance are also attained. Through subsequent pathways analysis we find that achieving net zero or even net negative operational and embodied emissions is feasible with more ambitious action in key areas, including increasing the share of mass-timber buildings and reducing end-of-life losses in sequestered carbon. [ABSTRACT FROM AUTHOR]

• MLR and RF were used to estimate current SOC stocks in south-eastern Australia. • Rainfall and minimum temperature were major drivers in determining SOC stocks. • The multi-GCM ensemble means suggested an overall decrease in SOC stocks. • The largest mean decrease of SOC stocks occurs in the high-rainfall alpine regions. Soil organic carbon (SOC) plays a key role in the sequestration of carbon that could otherwise be warming the atmosphere. Climate change including increased temperature and changed rainfall will greatly impact the global SOC cycle. There are still significant gaps in our knowledge of the size of the global SOC pool and how future climate will affect SOC stocks and flows in many parts of the world, including Australia. In this study, we used SOC data in a Digital Soil Mapping framework to predict current and future SOC stocks across the state of New South Wales (NSW) in south-eastern Australia. In the first phase of the study we estimated the current SOC stock using multiple linear regression (MLR) and random forest (RF) modelling, and in the second phase we projected the change of SOC stocks in the near future (2050s) and far future (2090s) under two Shared Socio-economic Pathways (SSPs) scenarios based on 25 global climate models (GCMs) from the Coupled Model Inter-comparison Project Phase 6 (CMIP6). Our spatial modelling showed that estimated current SOC stocks in NSW decreased from east to west. Multi-GCM ensemble means suggested SOC stocks would decrease by 7.6–12.9% under SSP2-4.5 and 9.1–20.9% under SSP5-8.5 across NSW under future climate. The extent of change in SOC stocks varied spatially with the largest mean decrease of SOC stocks occurring in the North Coast and South East (alpine) regions of NSW. Our findings can support decision-making in land management and climate change mitigation strategies in NSW at the regional level. Furthermore, the modelling methods can be applied to other areas where edaphic and landscape properties, land use, and climate data are available. [ABSTRACT FROM AUTHOR]

Restoration of coastal and marine ecosystems is essential to meet both national and global conservation targets and to counteract declines in coastal marine ecosystems. However, despite its status as a world leader in marine protection, Australia is lagging behind other countries in the implementation of coastal and marine restoration. Effective legislative frameworks that support the implementation of coastal and marine restoration as a management tool remains a key barrier to large-scale implementation of coastal and marine restoration in Australia and many other regions. We analyzed restoration projects and their policy frameworks in Australia, North America and Europe to identify the range of policy approaches for marine and coastal restoration. We then evaluated the legislative frameworks for coastal and marine restoration in two states in Australia (Queensland and New South Wales), to assess the current restoration permitting process and identify how different legislative and policy approaches could facilitate coastal and marine restoration projects. We identified two specific areas where improvements could be made to facilitate marine coastal restoration in Australia: increased transparency and better integration into coastal policy. Coastal and marine restoration in Australia is undertaken without appropriate and effective policy at the local, regional and national levels, which likely impedes its broader use as a management strategy. The policy and legislative changes and amendments outlined in this article can streamline the coastal and marine restoration process and thereby improve uptake of marine and coastal restoration in Australia. • Marine ecosystem restoration in Australia faces barriers because of inadequate and uncoordinated legislative frameworks. • Marine restoration could be better facilitated through increased transparency and integration into coastal planning policy. • Policy that supports the growing field of marine restoration for climate change mitigation will improve coastal resilience. [ABSTRACT FROM AUTHOR]

• The economics of carbon sequestration in South Australia were evaluated. • Results confirm active afforestation is a high-cost abatement option. • Conservative carbon accounting methods further limit incentives for land-use change. • Achievable abatement is likely small relative to emissions at recent carbon price. • Changes to Australian carbon accounting could incentivise more land-use change. Governments globally are developing increasingly ambitious carbon emissions reduction schemes that include significant emissions offset credits for forest-based carbon sequestration. Such strategies can present significant challenges in highly modified and intensively farmed regions where forest land use opportunity and establishment costs are high. This article evaluates the economics of land-use change via active afforestation for local carbon abatement in the Australian state of South Australia, a region with high supply costs representative of long-established temperate farming regions. We found that there is no economically viable abatement below $38 tCO 2 e−1, however up to 154 Mt CO 2 e of abatement could be available up to prices of $50 tCO 2 e−1. Variation in current Australian Emissions Reduction Fund (ERF) policy parameters related to permanence and crediting periods were also assessed. Recent ERF contracts involve a 100-year land-use change commitment (permanence period) and a 25-year crediting period where payments for growth in carbon from the land-use change is contracted. We compared outcomes of this arrangement to a scenario with equal 100-year permanence and crediting periods. We found substantial differences in carbon supply at some price points for a 25 rather than a 100-year crediting period. Under ERF parameters the first economically viable revegetation options occur at $42 tCO 2 e−1, however, we found a 69 percent reduction in economically viable supply at a carbon price of $50 tCO 2 e−1. The results highlight the role offset crediting policy can have on dis-incentivising land-use change and the need for landholders to be compensated fully for temporal opportunity costs. [ABSTRACT FROM AUTHOR]

• A techno-economic equation-based methodology for optimal design and operation of integrated solvent-based post-combustion carbon capture. • Absorber and desorber design using a rate-based model. • Consideration of a wide range of design and operation parameters concurrently in the optimisation procedure. • The results indicate the marked dependence of the system variables on the decision makers' objectives. • A case-study on two different objective functions demonstrates how one leads to the lowest possible total capital cost while the other minimises levelized carbon capture cost. A techno-economic equation-based methodology is developed for optimal design and operation of integrated solvent-based post-combustion carbon capture (PCC) processes using a rate-based model for the interaction of gas and liquid. The algorithm considers a wide range of techno-economic design and operation parameters such as number of absorber/desorber columns, height of columns, diameter of columns, operating conditions (P, T) of columns, pressure drop, packing type, percentage of CO 2 mitigated, captured CO 2 purity, amount of solvent regeneration, flooding velocities of columns, and number of compression stages. A case study is conducted to showcase two common objective-functions i) minimizing total capital investment, and ii) minimizing levelized capture costs, both for a 300 MW coal-power plant in Australia. The former objective leads to the lowest possible total capital cost of $312.4 M corresponding to levelized carbon capture cost of 58.1 $/tonne−CO 2. For objective (ii), however, the lowest levelized carbon capture cost is found to be around ten percent lower (52.8 $/tonne−CO 2), though it leads to a higher total capital cost ($325.2 M). The results indicate that the design and operation variables are markedly interactive, and no unique optimal design exists which can deliver all desired outcomes at once. Therefore, decisions on the selection of right variables become dependent on the decision-makers techno-economic objectives. [ABSTRACT FROM AUTHOR]

• We assess the potential inclusion of blue carbon within Australia's Emissions Reduction Fund, emphasizing issues and approaches that have global relevance. • We identify twelve potential management actions then quantify and discuss the five most promising activities, encompassing the protection, restoration and creation of mangroves, tidal marshes and seagrasses. • On a per area basis, mean abatement intensity of organic carbon was highest for the management activity ' (re)introduction of tidal flow' which may result in mean annual abatement of 13 – 15 Mg C org ha−1 yr−1 for mangrove and 6 – 8 Mg C org ha−1 yr−1 for tidal marsh. • Our approach offers a template that uses best available information to identify options for carbon abatement through management of coastal landscapes. There is increasing interest in protecting, restoring and creating 'blue carbon' ecosystems (BCE; mangroves, tidal marshes and seagrasses) to sequester atmospheric CO 2 -C and thereby contribute to climate change mitigation. While a growing number of countries aspire to report greenhouse gas emission and carbon sequestration changes from these ecosystems under voluntary international reporting requirements, few countries have domestic policy frameworks that specifically support the quantification and financing of carbon emission abatement through BCE management. Australia, as home to approximately 5–11% of global blue carbon stocks, has a substantial interest in the development of blue carbon policy. Here we assess the potential inclusion of blue carbon within Australia's Emissions Reduction Fund, emphasizing issues and approaches that have global relevance. We used a participatory workshop of scientific experts and carbon industry stakeholders to identify blue carbon management actions that would meet the requirements of the Fund. In total, twelve actions were assessed for their greenhouse gas emission abatement potential and the ability to measure abatement reliably, using a combination of available data and qualitative and quantitative methods, including expert knowledge. We identify and discuss the five most relevant and promising activities, encompassing the protection, restoration and creation of mangroves, tidal marshes and seagrasses. On a per area basis, mean abatement intensity of organic carbon (C org) was highest for the (re)introduction of tidal flow resulting in establishment of mangrove (13–15 Mg C org ha−1 yr−1) and tidal marsh (6–8 Mg C org ha−1 yr−1), followed by land use planning for sea-level rise for the creation of new mangrove habitat (8 Mg C org ha−1 yr−1). The avoided disturbance of existing mangroves, tidal marshes and seagrasses has the twofold benefit of avoiding remineralisation of existing stocks, plus the future annual abatement associated with the net sequestration of atmospheric CO 2 -C as C org with the continued functioning of these BCE. Our approach offers a template that uses best available information to identify options for carbon abatement through management of coastal landscapes, and details current knowledge gaps and important technical aspects that need to be considered for implementation in carbon crediting schemes. [ABSTRACT FROM AUTHOR]

• Regenerative agriculture facilitates climate change adaptation and mitigation. • Transitioning from conventional to regenerative agriculture can be challenging. • Transformation occurs across personal, practical and political spheres. • Personal transformation can be facilitated through learning and induced epiphanies. • Transitions are navigated (and sustained) through zones of friction and traction. Regenerative agriculture, an alternative form of food and fiber production, concerns itself with enhancing and restoring resilient systems supported by functional ecosystem processes and healthy, organic soils capable of producing a full suite of ecosystem services, among them soil carbon sequestration and improved soil water retention. As such, climate change mitigation and adaptation are incidental to a larger enterprise that employs a systems approach to managing landscapes and communities. The transformative potential of regenerative agriculture has seen growing attention in the popular press, but few empirical studies have explored the processes by which farmers enter into, navigate, and, importantly, sustain the required paradigm shift in their approach to managing their properties, farm businesses, and personal lives. We draw on theories and insights associated with relational thinking to analyze the experiences of farmers in Australia who have undertaken and sustained transitions from conventional to regenerative agriculture. We present a conceptual framework of "zones of friction and traction" occurring in personal, practical, and political spheres of transformation that both challenge and facilitate the transition process. Our findings illustrate the ways in which deeply held values and emotions influence and interact with mental models, worldviews, and cultural norms as a result of regular monitoring; and how behavioral change is sustained through the establishment of self-amplifying positive feedbacks involving biophilic emotions, a sense of well-being, and an ever-expanding worldview. We conclude that transitioning to regenerative agriculture involves more than a suite of 'climate-smart' mitigation and adaptation practices supported by technical innovation, policy, education, and outreach. Rather, it involves subjective, nonmaterial factors associated with culture, values, ethics, identity, and emotion that operate at individual, household, and community scales and interact with regional, national and global processes. Findings have implications for strategies aimed at facilitating a large-scale transition to climate-smart regenerative agriculture. [ABSTRACT FROM AUTHOR]