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Many governments have set ambitious targets for tree planting and increased woodland cover as a key part of actions to reach net‐zero carbon emissions by 2050. However, many uncertainties remain concerning how and where to expand tree cover, what species to plant, and how best to manage new plantations. Much contemporary forestry has been based on even‐aged monocultures, largely because of perceived advantages for timber production. However, in order to play a key role in climate change mitigation future forests will have to achieve timber production (and wider ecosystem service provision) alongside resilience to biotic and abiotic challenge. It is therefore crucial that appropriate informed decisions are made with regard to the structure, composition, and planning of future forests, in order to provide sustainable solutions that provide environmental, economic, and health benefits to society. Genetically diverse, mixed, and irregular forests, with their higher biodiversity and niche complementarity, are promising new forest configurations for regulating the water cycle, storing carbon, and delivering other goods and services. In the following discussion, we have used UK information to illustrate the benefits of mixed woodland versus monocultures and highlighted current issues related to government initiatives and policies for current and future forests. However, similar issues and problems are encountered globally. [ABSTRACT FROM AUTHOR]

Decarbonizing industrial sectors is a critical global challenge, involving the creation of new industrial spaces—'net zero industrial clusters'—co‐locating energy sectors and 'hard‐to‐abate' industries such as oil refining and steelmaking. This paper provides the first empirically grounded geographical investigation of these emerging spaces. It employs a place‐based research agenda to unpack how UK net zero industrial clusters (ICs) are imagined and emplaced in policy and industry discourses through place‐based naming, spatial configuring and mapping activities. By conducting document analysis, 33 in‐depth stakeholder interviews and five field trips to three UK case studies, we show how cluster imaginaries vary across cases and policy contexts in terms of constituents, focus and purpose. Ontological complexity is compounded by different rationales among stakeholders in configuring clusters and by contested cluster naming and boundary setting. This ambiguous, evolving spatiality raises important political and justice concerns over who and where is excluded in cluster building. These findings advance the geographies of low‐carbon transitions by showing: (1) ways that ICs' spatial embeddedness, which underlies cluster spatial configurations, helps increase industry actors' recognition of their economic, social and cultural ties with the places of their making, even if this risks path dependency; (2) how fluid cluster boundaries, reflected in cluster names and maps, emphasize the value of a network topology of scale to enable spatially inclusive, multi‐scalar climate mitigation. Finally, we argue that a place‐sensitive net zero policy mindset is vital for fulfilling ICs and the UK's decarbonization potential in a manner that is both fair and locally grounded. [ABSTRACT FROM AUTHOR]

Achieving ambitious carbon reduction targets requires transformative change to society, with behaviour change playing an important role. Climate change mitigation ('net zero') policies are needed to accelerate and support such behaviour change. This study examined factors and framing effects in public support for net zero policies in the United Kingdom (UK), making use of a large probability sample (ntotal = 5,665) survey conducted in August 2021. It found that net zero policies are widely supported, with only taxes on red meat and dairy products being supported by less than half of the UK public. Climate worry and perceived fairness were the strongest and most consistent predictors of policy support for net zero policies. The results further suggest that support for net zero policies can be increased by emphasising the co-benefits of the policies, in particular where they are beneficial for health. However, the framing effects were very small. In contrast, public support for net zero policies is lower when potential lifestyle and financial costs are mentioned. This suggests that perceived fairness of the distribution of costs and lifestyle implications of policies are crucial for building and maintaining support for net zero. [ABSTRACT FROM AUTHOR]

Background: Evidence is needed to support local action to reduce the adverse health impacts of climate change and maximise the health co-benefits of climate action. Focused on England, the study identifies priority areas for research to inform local decision making. Methods: Firstly, potential priority areas for research were identified from a brief review of UK policy documents, and feedback invited from public and policy stakeholders. This included a survey of Directors of Public Health (DsPH) in England, the local government officers responsible for public health. Secondly, rapid reviews of research evidence examined whether there was UK evidence relating to the priorities identified in the survey. Results: The brief policy review pointed to the importance of evidence in two broad areas: (i) community engagement in local level action on the health impacts of climate change and (ii) the economic (cost) implications of such action. The DsPH survey (n = 57) confirmed these priorities. With respect to community engagement, public understanding of climate change's health impacts and the public acceptability of local climate actions were identified as key evidence gaps. With respect to economic implications, the gaps related to evidence on the health and non-health-related costs and benefits of climate action and the short, medium and longer-term budgetary implications of such action, particularly with respect to investments in the built environment. Across both areas, the need for evidence relating to impacts across income groups was highlighted, a point also emphasised by the public involvement panel. The rapid reviews confirmed these evidence gaps (relating to public understanding, public acceptability, economic evaluation and social inequalities). In addition, public and policy stakeholders pointed to other barriers to action, including financial pressures, noting that better evidence is insufficient to enable effective local action. Conclusions: There is limited evidence to inform health-centred local action on climate change. More evidence is required on public perspectives on, and the economic dimensions of, local climate action. Investment in locally focused research is urgently needed if local governments are to develop and implement evidence-based policies to protect public health from climate change and maximise the health co-benefits of local action. [ABSTRACT FROM AUTHOR]

Background: Climate change is one of the greatest threats to public health in this century. The UK is one of six countries that has enshrined in law a commitment to become net zero by 2050. However, there is a lack of guidance and structure for local government in the UK, which has responsibility for public health, to reach this goal and help their communities mitigate and adapt to the health and health inequality impacts of climate change. This study aimed to identify common barriers and facilitators related to addressing the health and health inequality impacts of climate change in local governments. Methods: Using Normalisation Process Theory, we developed a two-round survey for people working in local authorities to identify the barriers and facilitators to including the health and health inequality impact of climate change in their climate action plans. The survey was delivered online via Qualtrics software. In the first-round respondents were able to express their views on barriers and facilitators and in the second round they ranked common themes identified from the first round. Two hundred and fifty people working in local government were invited to take part and n = 28 (11.2%) completed the first round of the survey and n = 14 completed the second round. Thematic analysis was used in Round 1 to identify common themes and weighted rankings were used to assess key barriers and facilitators in Round 2. Results: Key facilitators were the need to save money on energy, and successful partnership working already in place including across local government, with local communities and external stakeholders. Key barriers were insufficient staff, resources and lack of support from management/leaders, and lack of local evidence. Conclusion: To mitigate and adapt to the health impacts of climate change, local government must nurture a culture of innovation and collaboration to ensure that different departments work together This means not just working with external partners, but also collaborating and co-producing with communities to achieve health equity and mitigate the debilitating effect of climate change on public health. [ABSTRACT FROM AUTHOR]

With this paper we explore and discuss the priorities of and possible goal conflicts between authenticity and climate change in heritage gardens. How can climate change mitigation, adaptation, resilience, and cultural heritage conservation be combined in heritage gardens? Our study was guided by the following research question: How do gardeners negotiate climate change and authenticity in heritage gardens? From Rachel Carson's Silent Spring in the 1960s through to the 2002 report Gardening in the Global Greenhouse and the recent Gardening in a Changing World in 2022 mankind's impact on the environment and the emerging climate change has been the focus of increasing attention. By investigating and interviewing multiple gardeners our objective was to pinpoint common challenges, as well as what can be learned from one another within the field of gardening and heritage conservation. The case study method was adopted for this study, involving three head gardeners in the United Kingdom. Interviews were conducted with Joseph Atkin at Aberglasney Gardens, Claire Greenslade at Hestercombe Gardens, and Steve Lannin at Iford Manor about their expertise and knowledge. The gardeners expressed concern regarding climate change and the challenges it poses. The interviewees shared their experience with drought, reduced use of pesticides and herbicides, and the peat legislation in relation to their role as head gardeners. We argue that authenticity and the traditional gardening practised before the advent of power tools, plastic, peat issues, and uninformed transportation can be part of the solution to loss of biodiversity and climate change. This paper identifies some of the obstacles encountered in relation to negotiating questions of authenticity and climate change in heritage gardens. [ABSTRACT FROM AUTHOR]

Greenhouse gas stabilisation in the atmosphere is one of the most pressing challenges of this century. Sequestering carbon in the soil by changing land use and management is increasingly proposed as part of climate mitigation strategies, but our understanding of this is limited in quantitative terms. Here we collate a substantial national and regional data set (15790 soil cores), and analyse it in an advanced statistical modelling framework. This produced new estimates of the effects of land use on soil carbon stocks in the UK, different in magnitude and ranking order from the previous best estimates. Soil carbon stocks were highest in woodlands, followed by rough grazing and semi-natural grasslands, then improved grasslands, and lowest in croplands. Estimates were smaller than the previous estimates, partly because of new data, but mainly because the effect is more reliably characterised using a logarithmic transformation of the data. With the very large data set analysed here, the uncertainty in the differences among land uses was small enough to identify consistent mean effects. However, the variability in these effects was large, and this was similar across all surveys. This has important implications for agri-environment schemes, seeking to sequester carbon in the soil by altering land use, because the effect of a given intervention is very hard to verify. We examined the validity of the "space-for-time" substitution, and although the results were not unequivocal, we estimated that the effects are likely to be over-estimated by 5-33%, depending upon land use. [ABSTRACT FROM AUTHOR]

We present the results of a study on the climate forcing effects of replacing coal for power generation in the United Kingdom (UK) with wood pellets produced in northern Ontario, Canada. Continuous wood pellet production from two biomass sources were considered: fiber from increased harvesting of standing live trees (stemwood scenario) and from harvest residue provided by ongoing harvesting operations (residue scenario). In both scenarios, biomass was collected from harvesting operations in two forest management units (FMUs) with contrasting harvest residue treatments: natural decay of slash piles in the Hearst FMU and slash pile burning in the Kenora FMU. Life cycle emissions associated with wood pellets were assessed for production, transportation, and combustion to replace coal at a hypothetical power generating station in the UK. Greenhouse gas (GHG) emissions and removals in wood pellet and coal scenarios were assessed using two methods: global warming potential (GWP)-based mass balance and dynamic life cycle assessment (LCA) approaches. In the stemwood scenario, climate change mitigation from replacing coal with wood pellets was not achieved within the study timeline (2020–2100). In the residue scenario, immediate climate change mitigation was achieved with fiber sourced from the Kenora FMU where the current practice is to burn slash piles; for the Hearst FMU, where slash is allowed to decompose in the forest, climate change mitigation occurred 11.6 and 3.1 years after biomass collection began, as assessed by the mass balance and dynamic LCA methods, respectively. Factors affecting mitigation potential in the studied scenarios are discussed. [ABSTRACT FROM AUTHOR]

The vehicle emissions testing programme was conducted by the UK Department of Transport in 2016 in response to emissions tampering exposed in the Volkswagen (VW) emissions scandal. The programme identified large emissions discrepancies between real-world and in-lab testing across a range of Euro 5 and Euro 6 diesel passenger vehicles. The large vehicle test fleet reflects the current challenges faced in controlling vehicle emissions. This paper presents the following findings: NOx emissions are altered due to exhaust gas recirculation mismanagement. A new Real-Life Emissions methodology is introduced to improve upon the current Real Driving Emissions standard. A large and concerning emissions divergence was discovered between the achieved NOx improvement and deterioration of CO2. The findings act as catalysts to improve vehicle emissions testing beyond standards established since the VW scandal, aiding in the development of better climate change mitigation strategies and bring tangible air quality improvements to the environment. [ABSTRACT FROM AUTHOR]

An increase in extreme weather events is leading to increased flood occurrence and risk in many areas. Although climate mitigation strategies are being implemented, it is widely accepted that societies must adapt to climate variability and climate change. Traditional climate change impact studies have used projections for future time‐slices, often for a range of possible emissions scenarios. Recently however, there has been a move to instead consider climate change impacts relative to global mean surface temperature (GMST) change, to try to encourage action to avoid the more severe impacts from higher GMST changes. To support adaptation planning, more localised information on impacts is required. Here, data on the potential range of changes in flood peaks is generated by combining flood response surfaces and the new UK Climate Projections 2018, for every river cell on a 1 km grid across Britain, for GMST changes of 1–4.5°C. The results show significant spatial variation, with impacts typically higher in the west than the east, and generally increasing with GMST change. Some southern regions show flood peak changes accelerating with GMST change. The changes in flood peaks can be translated into changes in flood inundation and associated flood risk under alternative adaptation assumptions. [ABSTRACT FROM AUTHOR]

Subtidal seabed sediments are one of the planet's biggest organic carbon stores, but have been poorly considered in nature‐based climate change mitigation. Protection of the seabed is predominantly through establishment of marine protected area (MPA) networks, but their emphasis on biodiversity may limit their carbon value. The United Kingdom has one of the most extensive networks of MPAs in the world, yet damaging human activities are excluded from only a small portion. We calculate that full protection of the MPA network would offer limited carbon benefit, due to below average organic carbon stocks and disturbance from mobile fishing gears when compared to the entire U.K. seabed. We find that inshore exclusion zones (where mobile gears are restricted from nearshore areas to benefit biodiversity and low‐impact fishers) could offer greater carbon benefits compared to MPAs. However, neither of these biodiversity‐focused protection strategies are as effective for seabed carbon as targeted protection. [ABSTRACT FROM AUTHOR]

Soils have the potential to sequester and store significant amounts of carbon, contributing towards climate change mitigation. Soil carbon markets are emerging to pay farmers for management changes that absorb atmospheric carbon, governed by codes that ensure eligibility, additionality and permanence whilst protecting against leakage and reversals. This paper presents the first global comparative analysis of farmland soil carbon codes, providing new insights into the range of approaches governing this global marketplace. To do this, the paper developed an analytical framework for the systematic comparison of codes which was used to identify commonalities and differences in approaches, methods, administration, commercialisation and operations for 12 publicly available codes from around the world. Codes used a range of mechanisms to manage additionality, uncertainty and risks, baselines, measurement, reporting and verification, auditing, resale of carbon units, bundling and stacking, stakeholder engagement and market integrity. The paper concludes by discussing existing approaches and codes that could be adapted for use in the UK and evaluates the need for an over-arching standard for soil carbon codes in the UK and internationally, to which existing codes and other schemes already generating soil carbon credits could be assessed and benchmarked. [ABSTRACT FROM AUTHOR]

Tree planting now forms a major part of the UK climate mitigation strategy, with targets to increase the forest cover from the current 13% to 17%–20% by 2050. A tree planting strategy on this scale requires a significant amount of planning, bringing together expertise from a wide range of practitioners. We highlight four key reasons why fungi should be considered in tree planting strategies: 1. Fungi can cause severe tree disease. 2. Fungi can cause significant human health burdens. 3. Forest soil carbon and nutrient cycling is controlled by fungi. 4. Climate change is already affecting fungi. Following from these four reasons, we explore the ways in which the negative effects of fungi, such as plant and human disease, can be mitigated against, whilst also protecting and promoting the benefits of fungi in carbon storage and biodiversity. Based on this, we outline seven guidelines which should be integrated into existing tree planting guidelines and UK policy: A. Monitor tree fungal disease emergence and spread, including in source material trade (e.g. seeds and saplings). B. Choose tree species combinations appropriate to the specific habitat and appropriate for biodiversity and carbon storage goals. C. Develop and implement a widely accessible fungal spore forecast to complement existing pollen forecasts. D. Protect existing ancient and mature woodlands. E. Promote planting on suitable land types, avoiding grasslands and wetlands. F. Assess proposed and existing forest sites, ideally using a combination of fungal fruit body surveys and eDNA techniques. G. Develop and implement the UK Fungi Red List into UK law. [ABSTRACT FROM AUTHOR]

Maximising resource‐use efficiency, productivity and environmental sustainability are all fundamental requirements to raise global food production by ~70 per cent in order to feed a world population of ~9.7 billion people by 2050. Perhaps the most vital resource within our capacity to achieve this goal is our soil. Broadly, the fundamental question concerns whether or not satisfying this production demand will accelerate soil degradation, climate change, and the loss of soil carbon stocks. This paper builds upon the outputs of the UK Charity 'Food & Farming Futures' (chaired by Lord Curry of Kirkharle) virtual workshop held on 23 March 2021, entitled 'Capturing the Potential of Soil'. The event focussed on the link between soil health, primarily soil organic carbon (SOC), and agricultural productivity. Supported with commentaries by Professor Pete Smith (University of Aberdeen and Science Director of the Scottish Climate Change Centre of Expertise) and Professor Steve McGrath (Head of Sustainable Agricultural Sciences at Rothamsted Research), specific focus will be given to the research challenges within the UK's ability to improve soil health and functionality, the implementation priorities that must be held in order to improve soil management by 2050 and what the potential co‐benefits could be. These co‐benefits were scattered across environmental, economic, social and political issues, yet they may be summarised into six primary co‐benefits: developing natural capital, climate change mitigation, carbon trading, improvements in crop yield, animal performance and human health (nutrition). Additionally, the main barriers to improved soil management practices are centred on knowledge exchange‐regarding agri‐environmental techniques—whilst the most impactful solutions rely on soil monitoring, reporting and verification. [ABSTRACT FROM AUTHOR]

Against the backdrop of a fragmented and evolving governance landscape, this paper examines how effective climate commissions are in engaging the public to co-produce local climate action in the UK. Climate commissions are emerging amid heightened concerns regarding the top-down style of policymaking on climate change and resource-constrained local authorities. However, less is known about how they engage the public who are pivotal for climate action, both in signalling greater ambition from governments and through their own mitigation and adaptation efforts. This paper draws on qualitative interviews with an array of individuals both inside and outside climate commissions in the UK, and utilises Cash's theoretical framework of 'salience, legitimacy and credibility' to assess how effective climate commissions are in engaging the public to co-produce local climate action. The findings indicate a discernible chasm between commissions and the broader public. Equally however, they provide hopeful perspectives into the effect that more collaborative engagement, that speaks to local concerns and leverages local knowledge, would have on commissions' 'salience, legitimacy and credibility' and, additionally, the legitimacy of local authorities. Moreover, they suggest that deeper collaboration with local networks of community groups, who are not yet represented on commissions, could foster more sustained climate action. It concludes by considering the novel implications of these emergent insights for the Cash framework and what this means for commissions in their future engagement with the public. • Knowledge co-production resonates in both theory and practice. • Local and grassroot action is critical to meet climate mitigation and adaptation goals. • Ensuring 'salience, legitimacy and credibility' can lead to more effective climate policy. • Climate commissions need to better leverage local knowledge to drive climate action. • Community groups are under-utilised in climate conversations and decision-making. [ABSTRACT FROM AUTHOR]

What makes a climate story effective? We examined if short fiction stories about everyday pro-environmental behaviours motivate climate policy support, and individual and collective climate action in a nationally representative experiment (N = 903 UK adults). The story featuring protagonists driven by pro-environmental intentions (i.e., the intentional environmentalist narrative) increased participants' support for pro-climate policies and intentions to take both individual and collective pro-environmental actions, more so than did stories featuring protagonists whose pro-environmental behaviours were driven by intentions to gain social status, to protect their health, and a control story. Participants' stronger feelings of identification with the protagonist partially explained these effects of the intentional environmentalist narrative. Results highlight that narrating intentional, rather than unintentional, pro-environmental action can enhance readers' climate policy support and intentions to perform pro-environmental action. Therefore, the intentions driving pro-environmental action may have implications for the extent to which observes identify with the actor and take pro-environmental action themselves. [ABSTRACT FROM AUTHOR]

[Display omitted] • Timeline of real driving passenger car emissions (1998 to 2022) in the UK constructed from remote sensing data. • Impact of the promotion and demise of diesel fuel on passenger car NO x emissions evaluated. • Promotion of diesel fuel in the UK led to 721 kt excess NO x emissions. • Rapid move away from diesel fuel had minor influence on UK emissions. The promotion and growth in the use of diesel fuel in passenger cars in the UK and Europe over the past two decades led to considerable adverse air quality impacts in urban areas and more widely. In this work, we construct a multi-decade analysis of passenger car emissions in the UK based on real driving emissions data. An important part of the study is the use of extensive vehicle emission remote sensing data covering multiple measurement locations, time periods, environmental conditions and consisting of over 600,000 measurements. These data are used to consider two scenarios: first, that diesel fuel use was not promoted in the early 2000s for climate mitigation reasons, and second, that there was not a dramatic decline in diesel fuel use following the Dieselgate scandal. The strong growth of diesel fuel use coincided with a time when diesel NO x emissions were high and, conversely, the strong decrease of diesel fuel use coincided with a time when diesel vehicle after-treatment systems for NO x control were effective. We estimate that the growth in diesel car use in the UK results in excess NO x emissions of 721 kt over a three decade period; equivalent to over 7 times total annual passenger car NO x emissions and greater than total UK NO x emissions of 681.8 kt in 2021 and with an associated damage cost of £5.875 billion. However, the sharp move away from diesel fuel post-Dieselgate only reduced NO x emissions by 41 kt owing to the effectiveness of modern diesel aftertreatment systems. [ABSTRACT FROM AUTHOR]

The saltmarsh carbon storage potential is a key topic in blue carbon research and climate policy. Ecosystem service valuations provide valuable information to policymakers for habitat management and climate change mitigation policies. Yet, only few saltmarsh valuation studies have included the carbon storage service in the UK context. This paper investigates how the public values saltmarsh ecosystem services, focussing on the carbon storage service. We used a choice experiment to elicit the willingness to pay (WTP) of a representative sample of the Scottish public to support interventions that would maintain or improve the provision of these services. Furthermore, we tested the effect of information on individuals' preferences and WTP with a split sample approach where one group received a treatment in the form of additional information. We found that (i) all attributes had a significant influence on individuals' choices; (ii) both groups had, on average, a positive marginal WTP for all presented ecosystem services; (iii) the treated sample had, on average, no significantly different marginal WTP for carbon storage than the control group. This paper adds to the limited literature on the saltmarsh carbon storage ecosystem service and demonstrates a developed nation's public's openness to nature-based climate change mitigation solutions. [Display omitted] • The Scottish public on average prefers saltmarsh management over the status quo. • Providing additional information reduced heterogeneity in WTP for carbon storage. • Most respondents preferred an improvement of all saltmarsh ecosystem services. • Therefore management should focus on both climate change mitigation and adaptation. [ABSTRACT FROM AUTHOR]

Food systems contribute 23–42% of global greenhouse gas emissions. Reducing food system emissions is an essential component of climate change mitigation, and a system-wide approach, including production, processing, trade and demand-side transformations, will be needed. Long-term analysis of greenhouse gas (GHG) emissions of food supply is crucial for informing this transformation, and understanding the processes contributing to existing trends can reveal opportunities for future mitigation strategies. To address these needs we used data on food supply, trade and emission intensity to quantify changes in GHG emissions between 1986 and 2017 resulting from food supply in the United Kingdom (UK). Uniquely, the relative contributions of supply-side and demand-side changes to historical trends in food emissions were assessed, and the gap between current UK food consumption and EAT-Lancet recommended diets was used to estimate the additional GHG emission reductions that could be achieved by shifting to the Planetary Health Diet (PHD). It was estimated that in the UK, per-capita GHG emissions from food fell by 32% (from 4.6 tCO 2 eq/capita to 3.1 tCO 2 eq/capita) between 1986 and 2017. Of this 32% reduction, 21% was due to supply-side changes (a fall in emission intensity per unit of production due to increased efficiency of farming practices), 10% was due to demand-side changes (including dietary change and waste reduction), and 2% was due to changing trade patterns. Relative to the PHD, however, the average UK citizen still greatly over-consumes beef, lamb and pork, tubers and starchy vegetables and dairy products, and under-consumes vegetables, nuts, and legumes. It was estimated that by adopting the PHD, UK per capita food emissions could be reduced by a further 42% to 1.8 tCO 2 eq/capita. These results expose the historic contributions of both supply- and demand-side changes to reductions in GHG emissions from food, and highlight the underutilised potential of dietary change in contributing to mitigation of GHG emissions from food. [Display omitted] • UK per-capita food emissions fell by 32% between 1986 and 2017. • Supply and demand-side changes contributed to this reduction. • Adopting the Planetary Health Diet could reduce emissions of UK food supply by 42%. • This reveals the underutilised potential of dietary change as a mitigation strategy. [ABSTRACT FROM AUTHOR]

Grasslands account for ∼30% of global terrestrial carbon (C), of which most is stored in soils and provide important ecosystem services including livestock and forage production. Reseeding of temporary grasslands on a 5-year cycle is a common management practice to rejuvenate sward productivity and reduce soil compaction, but is physically disruptive and may reduce soil organic carbon (SOC) stocks. However, research to date is limited, which impacts on the ability to optimise grassland management for climate change mitigation. To determine whether extending the time interval up to 20 years between grassland reseeding can increase stable SOC stocks, a soil survey was conducted across three UK grassland chrono-sequences comprising 24 fields on contrasting soil types. We found that grassland SOC stocks (39.8–114.8 Mg C ha−1) were higher than co-located fields in arable rotations (29.3–83.2 Mg C ha−1) and the relationship with grassland age followed a curvilinear relationship with rapid SOC stock accumulation in the year following reseeding (2.69–18.3 Mg C ha−1 yr−1) followed by progressively slower SOC accumulation up to 20 years. Contrary to expectation, all grasslands had similar soil bulk densities and sward composition questioning the need for traditional 5-year reseeding cycles. Fractionation of soils into stable mineral associated fractions revealed that coarse textured grassland topsoils (0–15 cm) were near-saturated in C irrespective of grassland age whilst loam soils reached saturation ∼10 years after reseeding. Fine-textured topsoils and subsoils (15–30 cm) of all textures were under saturated and thus appear to hold the most potential to accrue additional stable C. However, the lack of a relationship between C saturation deficit and grassland age in subsoils suggests that more innovative management to promote SOC redistribution to depth, such as a switch to diverse leys or full inversion tillage may be required to maximise subsoil SOC stocks. Taken together our findings suggest that extending the time between grassland reseeding could temporarily increase SOC stocks without compromising sward composition or soil structure. However, detailed monitoring of the trade-offs with grassland productivity are required. Fine textured soils and subsoils (15–30 cm) have the greatest potential to accrue additional stable C due to under saturation of fine mineral pools. • Reseeding of grasslands is disruptive and may reduce soil organic carbon stocks. • A soil C survey of grassland chronosequences was conducted across three UK farms. • Soil C stocks were related to age with rapid initial increases after reseeding. • Fine textured soils and subsoils were under saturated and could accrue additional C. • Use of diverse leys and full inversion tillage may increase subsoil soil C stocks. [ABSTRACT FROM AUTHOR]

Waste-related methane (CH 4) emissions could account for 31% of total UK CH 4 emissions. Waste management strategies in the UK have recently changed as more waste is diverted from landfills to anaerobic digesters (AD) and composting facilities, which can be significant sources of CH 4. In this study, we combined mobile CH 4 emissions data from waste treatment facilities to perform a life cycle assessment of current biowaste treatment and potential future mitigation, including AD, in-vessel composting, incineration, and landfilling scenarios. We found that diverting biowaste from landfill to AD is an effective strategy, but it is not enough to eliminate emissions. The fugitive CH 4 emissions from anaerobic digesters have a significant impact on the environmental sustainability of waste management strategies, with upgrading the biogas into biomethane being the best option for climate change mitigation, in the case where natural gas is replaced. A change in the biowaste strategy can also reduce CH 4 emissions from the waste sub-sector analysed, from 58.2 to 30.3 kilotonnes per year, an emissions saving of approximately 52%. However, with these technologies, net-zero emissions is challenging unless the absolute minimum emissions from the treatment technologies is consistently achieved. Therefore, we strongly recommend a focus on mitigating CH 4 emissions from AD to achieve the goal of net-zero waste management. [Display omitted] • The UK's biowaste strategies are evaluated using seven different scenarios. • Anaerobic digestion, in-vessel composting, incineration and landfill considered. • The range of methane emissions affect technology's environmental sustainability. • Biomethane generation from anaerobic digestion provides the greatest GWP saving. • Meeting the Net Zero goal in the waste sector is challenging. [ABSTRACT FROM AUTHOR]

Countries' emission reduction commitments under the Paris Agreement have significant implications for lifestyles. National planning to meet emission targets is based on modelling and analysis specific to individual countries, whereas global integrated assessment models provide scenario projections in a consistent framework but with less granular output. We contribute a novel methodology for translating global scenarios into lifestyle implications at the national and household levels, which is generalisable to any service or country and versatile to work with any model or scenario. Our 5Ds method post-processes Integrated Assessment Model projections of sectoral energy demand for the global region to derive energy-service-specific lifestyle change at the household level. We illustrate the methodology for two energy services (mobility, heating) in two countries (UK, Sweden), showing how effort to reach zero carbon targets varies between countries and households. Our method creates an analytical bridge between global model output and information that can be used at national and local levels, making clear the lifestyle implications of climate targets. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) is at the interface of biowaste management, energy generation, food production and land-based carbon dioxide removal. Strategic deployment of AD requires careful scoping of interactions with prospective alternative biowaste management, energy generation technologies and land uses to ensure effective delivery of climate neutrality and circularity. There remains a need to assess the greenhouse gas (GHG) mitigation efficacy of AD in the context of future alternative (counterfactual) processes associated with differential rates of decarbonisation across energy, waste management and land (including agriculture) sectors. To address this gap, prospective life cycle assessment (LCA) is applied to AD deployment scenarios across three decarbonisation contexts, using the UK as an example. Food waste prevention and diversion to animal feed always achieve more GHG mitigation than AD, even with sustainable intensification of food and feed production. Compared with maize- or grass-biomethane transport fuel, solar electricity generation can avoid 16 times more fossil energy and afforestation can mitigate six times more GHG per hectare of land occupied. Transport biomethane is currently the most effective biogas use for GHG mitigation, but large-scale combustion of biogas for electricity or industrial heat generation is the most effective long-term option as transport is electrified and bioenergy carbon capture & storage (BECCS) is deployed. Prioritising waste prevention and diversion to animal feed (including via insect meal) instead of maximising AD deployment could simultaneously: offset an additional 10–15% of national GHG emissions; meet an additional 2–4% of national energy demand; free enough arable land to provide 20–21% of national recommended protein and kcal intake. However, AD is likely to remain the best option to manage substantial volumes of residual food wastes and manures that will remain available even if ambitious projections on waste prevention and diet change are realised. [Display omitted] • Consequential LCA of anaerobic digestion (AD) in future decarbonisation contexts • GHG mitigation efficacy of AD declines as energy & transport systems decarbonise • AD-crop cultivation is a highly inefficient land use for energy generation and GHG mitigation • Carbon capture & storage could maintain effective mitigation from large-scale biogas use • Sustainable niche for waste-AD alongside waste prevention & diversion to animal feed [ABSTRACT FROM AUTHOR]