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In recent years, the target of reaching “net zero” emissions by 2050 has come to the forefront of global climate politics. Net zero would see carbon emissions matched by carbon removals and should allow the planet to avoid dangerous climate change. But the recent prominence of this goal should not distract from the fact that there are many possible versions of net zero. Each of them will have different climate justice implications, and some of them could have very negative consequences for the world's poor. This article demonstrates the many ambiguities of net zero, and argues in favor of a net zero strategy in which those who can reasonably bear the burden adopt early and aggressive mitigation policies. We also argue for a net zero strategy in which countries place the lion's share of their faith in known emissions reduction approaches, rather than being heavily reliant on as-yet-unproven “negative emissions techniques.” Our overarching goal is to put net zero in its place, by providing a clear-sighted view of what net zero will achieve, and where the “net” in net zero needs to be tightened further if the world is to achieve climate justice.

According to one prominent theory of development, a country’s wealth is primarily explained by the quality of its institutions. Leaning on that view, several political theorists have defended two normative conclusions. The first is that we have no reason for concern, from the point of view of justice, if some countries have greater natural resource endowments than others. The second is that proposals for redistribution across borders are likely to be superfluous. Advocates of global redistribution have not yet grappled with these momentous arguments, or shown whether, and how, they might be rebuffed. This article does just that.

Opportunity costs can represent a significant portion of the costs associated with conservation projects and frequently outstrip other kinds of cost. They are typically understood to refer to the benefits someone would have obtained if conservation projects had not required them to give up current activities, such as farming or hunting or if the land had been available for uses other than conservation. This familiar way of identifying opportunity costs is flawed, however, because it threatens to condone, or take advantage of, the injustices that many people face that affect their opportunities. I integrated ideas from the political theory of global justice to examine how the analysis of opportunity costs illustrates the importance of considering conservation and issues of global justice together, rather than thinking about them in isolation. I distinguish four baselines for defining opportunity costs. A status quo baseline defines opportunity costs by asking what people would have earned had a conservation project not happened. A willingness to accept baseline defines them by asking people what it would take to make them indifferent to whether a conservation project takes place or not. An antipoverty baseline suggests that opportunity costs have been met when people affected by a project are not left in poverty. An egalitarian baseline suggests opportunity costs have been met when people are not left in relative disadvantage, with worse than average opportunities. I argue that the egalitarian baseline is the most acceptable from the point of view of justice. Such a baseline would suggest that, in practice, many of the world's poor are being unjustly treated, or even exploited, as a result of conservation activities.Los costos de oportunidad pueden representar una porción significativa de los costos asociados con los proyectos de conservación y con frecuencia superan otros tipos de costos. Comúnmente se entiende que estos costos se refieren a los beneficios que alguien habría obtenido si los proyectos de conservación no los hubieran requerido para renunciar a ciertas actividades, como la agricultura o la cacería, o si la tierra hubiera estado disponible para otros usos además de la conservación. Sin embargo, esta manera familiar de identificar los costos de oportunidad es defectuosa ya que amenaza con perdonar, o aprovechar, las injusticias que muchas personas enfrentan y que afectan sus oportunidades. Integré ideas de la teoría política de la justicia global para examinar cómo el análisis de los costos de oportunidad ilustra la importancia de considerar en conjunto la conservación y los temas de justicia global, en lugar de considerarlos de manera aislada. Distingo cuatro líneas base para definir los costos de oportunidad. Una línea base de orden establecido define los costos de oportunidad al preguntar a las personas lo que habrían obtenido de no haberse realizado un proyecto de conservación. Una línea base de la voluntad de aceptación las define al preguntar a las personas qué necesitarían para volverse indiferentes a si se realiza o no un proyecto de conservación. Una línea base de antipobreza sugiere que los costos de oportunidad se han cumplido cuando las personas afectadas por un proyecto no quedan en la pobreza. Una línea base igualitaria sugiere que los costos de oportunidad se han cumplido cuando las personas no quedan en una desventaja relativa, con peores oportunidades al promedio. Argumento que la línea base igualitaria es la más aceptable desde el punto de vista de la justicia. Dicha línea base sugeriría que, en la práctica, muchas de las personas que viven en pobreza son tratadas injustamente, o incluso explotadas, como resultado de las actividades de conservación.机会成本可以代表保护项目成本的很大一部分, 并且经常超过其他类型的成本。机会成本通常被理解为, 当保护项目不要求参与者放弃目前的活动(如耕作或狩猎), 或当土地可用于保护以外的用途时, 人们获得的利益。然而, 这种确定机会成本的常用方式存在着缺陷, 因为它有可能纵容或利用许多人所面临的影响其机会的不公正现象。本文整合了全球正义政治理论的观点, 以研究机会成本分析如何说明综合而非孤立地思考保护和全球正义问题的重要性。研究者区分了定义机会成本的四种基线。现状基线通过询问人们在没有保护项目的情况下会获得什么来定义机会成本。意愿基线通过询问人们需要什么才能使他们不在意是否开展保护项目来定义机会成本。反贫困基线认为, 只要受项目影响的人没有陷入贫困就满足了机会成本。而平等主义基线则认为, 当人们没有处于相对不利的地位、没有比平均机会更糟糕的时候, 机会成本才得到满足。研究者认为, 从正义的角度来看, 平等主义基线是最可以接受的。这种基线表明, 在实践中, 世界上许多贫困人口由于保护活动的开展而受到不公正的待遇, 甚至面临剥削。【翻译:胡怡思;审校:聂永刚】.

The school librarian is responsible for facilitating access to electronic resources, creating an awareness of these formats, and ensuring that the pupils and staff have the skills to exploit them effectively. Traditionally, these skills have been developed within the individual secondary and tertiary educational sectors. In the United Kingdom, skills acquisition and the implications of resource provision are being considered across secondary and tertiary education. The paper opens with an account of a study of the provision and use of electronic resources in tertiary education in the U.K. and then explores the implications of research into skills transfer between secondary schools and the tertiary sector.

The ocean is central to our lives, but many of our impacts on the ocean are highly unsustainable, and patterns of resource exploitation at sea are deeply inequitable. This article assesses whether the objectives encapsulated in the UN’s Sustainable Development Goal for the ocean are well equipped to respond to these challenges. It will argue that the approach underpinned by the SDG 14 is largely compatible, unfortunately, with ‘business as usual.’ SDG 14 is undoubtedly intended as a starting point rather than a final destination; but it is nevertheless important to be clear about how far we still need to travel on the road to oceanic justice. Most significantly, SDG 14 leaves several key challenges inadequately addressed or simply unaddressed. It fails to specify adequate principles for the fair sharing of benefits and burdens flowing from the ocean, including the burdens of tackling pressing environmental problems. Neither does it address the underlying causes of inequality in the ocean economy. It neglects to properly address, furthermore, the fragmented institutional context which significantly impedes effective action to advance the goals of justice and sustainability at sea. Finally, whereas SDG 14 correctly identifies a series of necessary reforms to the ocean economy, it fails to engage with important issues of transitional justice which will arise if these policies are implemented. Vital first step though it is, promoting a just and sustainable ocean will require us to set our sights considerably higher than the targets endorsed as part of SDG 14.

Dictatorship is a great stain upon our world. Dictators treat their subjects purely as means to their own aggrandizement, and not as agents with a right to participate in self‐government. Moreover, dictators frequently, though not always, commit great harms: starting wars, brutalizing dissidents, persecuting minorities, and squandering resources which could otherwise be used to advance the common good.The question of how outsiders—including outsiders living in societies committed in word, if not always in deed, to the core principles of liberal democracy—ought to engage with or respond to dictatorial regimes, though, is a thorny one. Difficult questions arise in the context of overseas aid, for instance, as states and NGOs grapple with how to act in a situation where their support might bolster repressive regimes. But the focus here will be upon international trade. In recent years, a number of scholars have argued that for liberal democracies to allow their citizens and corporations to trade with dictatorships can also serve to entrench dictators' positions, and even make the emergence of dictatorships more likely. ...

The maximum energy to which ions are accelerated in the interaction of a high power laser pulse with a thin foil target scales with the laser intensity, with a power-law that varies with the acceleration mechanism and laser pulse parameters. For fixed laser energy and pulse duration, maximizing the intensity by focusing to a smaller focal spot does not, however, necessarily result in higher-energy ions. For the case of relatively thick foil targets, it has been shown that self-generated magnetic fields and unfavourable changes to the temperature and divergence of the fast electron population injected into the target can result in lower-energy sheath-accelerated ions compared to that expected from intensity scaling laws. We report results from an investigation of the influence of laser focusing on ion acceleration in the ultrathin target regime, for which high energy protons have been achieved by our group [1]. We compare the interaction physics resulting from the use of f/3 and f/1 focusing geometries. Although f/1 focusing (achieved using a focusing plasma optic) produces a smaller nominal laser focal spot size and thus higher nominal peak intensity, more efficient ion acceleration to higher energies is achieved with the f/3 geometry for the case of expanding ultrathin foils undergoing relativistic self-induced transparency. Particle-in-cell simulations reveal that self-focusing in the expanding plasma produces a near-diffraction-limited focal spot, resulting in up to an order of magnitude higher focused intensity in the f/3 case. We also report on the extent to which this intensity enhancement is expected in the case of the short-pulse, ultrahigh-intensity regime that will soon be accessible using multi-petawatt lasers. The study is published in reference [2]. [1] A. Higginson et al., Nature Communications 9, 724 (2018) [2] T. P. Frazer et al., Phys. Rev. Research 2, 042015(R) (2020)

Optimisation of betatron X-rays and their applications, SPIE Optics + Optoelectronics, 2021

This chapter examines a variety of views about the nature of society’s putative duty to conserve natural resources for the future, with a focus on the contested idea of sustainability. This chapter examines competing conceptions of sustainability and their implications for natural resource conservation across generations. Sustainability is a very popular concept, but there are many different positions on what might be called the “sustainability of what?” question. The chapter examines a number of competing views and shows how controversy here has informed the debate between so-called weak and strong conceptions of sustainability. It concludes with an examination of the politics of sustainability, and in particular the connections and possible tensions between goals of natural resource conservation and of global justice.

Predicted sea level rise caused by anthropogenic climate change threatens to drastically alter coastlines around the world. In the case of low-lying atoll states, it threatens to expunge them from the map. This potential scenario has engendered considerable discussion concerning the fate of climate refugees. Relatively little attention, however, has been given to the impact of sea level rise on existing maritime zones and how these zones, and the resources they represent, might continue to benefit displaced communities. This article builds on the small body of legal scholarship that has taken this matter seriously, to provide a normative analysis, based on principles of global justice, of the best ways of responding to the plight of atoll states. The article thus both extends legal scholarship by applying the principles of global justice to the problem of maritime boundaries, and contributes to the literature on global justice by investigating a salient but hitherto neglected case.

This paper discusses the nature and conclusions of the second phase of a two-part project, CrossEd, undertaken between autumn 2004 and autumn 2005 and funded by the Joint Information Systems Committee in the UK. The study investigated collaborations taking place between secondary schools and universities in the provision of information literacy skilling relating to the use of e-resources. A survey of all university libraries in the UK was undertaken using an e-mail questionnaire to identify the incidence of current collaboration. The data from that survey provided information on the types of collaboration taking place. These were categorised and used to select the survey population of six university libraries for the qualitative study. Data collection was by means of face-to-face and telephone interviews with university librarians, using semistructured interview schedules. Six types of training for school pupils were identified, and the research revealed at least seven distinct positive aspects of cross-sectoral collaboration for school pupils. A fundamental lack of understanding of the respective roles of secondary school and university librarians was evident, and a range of issues to be addressed by librarians in both educational sectors was identified. A strategy for enhancing collaboration in the UK is also discussed.

High intensity lasers (>1019 W/cm2) produce relativistic electrons when they interact with matter. The high energy electrons upon incidence on a solid target produce secondary emissions like protons, neutrons, positrons, x-ray emission and γ-rays1. Gamma rays produce from this interaction can be used to induce photoneutron reaction in a material, thereby producing short-lived isotopes or isomers2. The isotopes or isomers produced can be used for diagnosing the radiation flux and directionality3. Materials with short half-lives (in μs to ms time scale) are of interest as a diagnostic for shot to shot measurement of parameters in high repetition lasers (10 Hz), since they decay well before the incidence of the subsequent pulse on the material. For understanding the working of this diagnostic, systematic studies of decay of the isotopes/isomers produced and the attenuation of γ-rays in the material are necessary. The design and efficiency of a diagnostic for characterizing γ-rays using the method of nuclear activation for 10 Hz high repetition laser is presented.

A high power laser was used to accelerate electrons in a laser-driven wakefield accelerator. The high energy electrons were then used to generate an x-ray beam by passing them through a converter target. This bremsstrahlung source was characterised and used to perform penetrative imaging of industrially relevant samples. The photon spectrum had a critical energy in excess of 100 MeV and a source size smaller than the resolution of the diagnostic ( ≲ 150 µm). Simulations indicate a significantly smaller source is achievable. Variations in the x-ray source characteristics were realised through changes to the plasma and converter parameters while simulations confirm the adaptability of the source. Imaging of high areal density objects with 150 µm resolution was performed, demonstrating the unique advantages of this novel source.

Laser-driven proton acceleration from ultrathin foils is investigated experimentally using F/3 and F/1 focusing. Higher energies achieved with F/3 are shown via simulations to result from self-focusing of the laser light in expanding foils that become relativistically transparent, enhancing the intensity. The increase in proton energy is maximised for an optimum initial target thickness, and thus expansion profile, with no enhancement occurring for targets that remain opaque, or with F/1 focusing to close to the laser wavelength. The effect is shown to depend on the drive laser pulse duration.

Relativistic electrons generated by the interaction of petawatt-class short laser pulses with solid targets can be used to generate bright x-rays via bremsstrahlung. The efficiency of laser energy transfer into these electrons depends on multiple parameters including the focused intensity and pre-plasma level. This paper reports experimental results from the interaction of a high intensity petawatt-class glass laser pulses with solid targets at a maximum intensity of 1019 W cm−2. In-situ measurements of specularly reflected light are used to provide an upper bound of laser absorption and to characterize focused laser intensity, the pre-plasma level and the generation mechanism of second harmonic light. The measured spectrum of electrons and bremsstrahlung radiation provide information about the efficiency of laser energy transfer.

An ever-increasing number of strong-field applications, such as ultrafast coherent control over matter and light, require driver light pulses that are both high power and spectrally tunable. The realization of such a source in the terahertz (THz) band has long been a formidable challenge. Here, we demonstrate, via experiment and theory, efficient production of terawatt (TW)-level THz pulses from high-intensity picosecond laser irradiation on a metal foil. It is shown that the THz spectrum can be manipulated effectively by tuning the laser pulse duration or target size. A general analytical framework for THz generation is developed, involving both the high-current electron emission and a time-varying electron sheath at the target rear, and the spectral tunability is found to stem from the change of the dominant THz generation mechanism. In addition to being an ultrabright source (brightness temperature of about 10^{21} K) for extreme THz science, the THz radiation presented here also enables a unique in situ laser-plasma diagnostic. Employing the THz radiation to quantify the escaping electrons and the transient sheath shows good agreement with experimental measurements.