Ocean iron fertilization (OIF) aims to remove carbon dioxide (CO 2 ) from the atmosphere by stimulating phytoplankton carbon‐fixation and subsequent deep ocean carbon sequestration in iron‐limited oceanic regions. Transdisciplinary assessments of OIF have revealed overwhelming challenges around the detection and verification of carbon sequestration and wide‐ranging environmental side‐effects, thereby dampening enthusiasm for OIF. Here, we utilize five requirements that strongly influence whether OIF can lead to atmospheric CO 2 removal (CDR): The requirement (a) to use preformed nutrients from the lower overturning circulation cell; (b) for prevailing iron‐limitation; (c) for sufficient underwater light for photosynthesis; (d) for efficient carbon sequestration; (e) for sufficient air‐sea CO 2 transfer. We systematically evaluate these requirements using observational, experimental, and numerical data in an “informed back‐of‐the‐envelope approach” to generate circumpolar maps of OIF (cost‐)efficiency south of 60°S. Results suggest that (cost‐)efficient CDR is restricted to locations on the Antarctic Shelf. Here, CDR costs can be <100 US$/tonne CO 2 while they are mainly >>1,000 US$/tonne CO 2 in offshore regions of the Southern Ocean, where mesoscale OIF experiments have previously been conducted. However, sensitivity analyses underscore that (cost‐)efficiency is in all cases associated with large variability and are thus difficult to predict, which reflects our insufficient understanding of the relevant biogeochemical and physical processes. While OIF implementation on Antarctic shelves appears most (cost‐)efficient, it raises legal questions because regions close to Antarctica fall under three overlapping layers of international law. Furthermore, the constraints set by (cost‐)efficiency reduce the area suitable for OIF, thereby likely reducing its maximum CDR potential.

Solar geoengineering (SG), or the proposed use of technology to reflect sunlight back to space as a means of partially counteracting climate change, requires systematic research funded by public bodies, yet no dedicated national SG research programs (“programs”) currently exist. To explain why and understand how things might change in the future, we add concepts from role theory, a research tradition focused on international relations and foreign policy analysis, to the Multiple Streams Approach, a theoretical framework developed to study agenda setting at the national level, to assess policy processes related to SG research in four countries: Germany, China, Australia, and the United States (US). The results of our analysis indicate that, among these four states, only the US might plausibly consider initiating a program under present conditions. Germany, China, and Australia appear likely to seriously consider comparable efforts only in response to a US program, although their reasons for doing so and specific program designs would differ. The source of this variation, we argue, is the different foreign policy paradigms—or “national role conceptions”—prevailing in each state, which mediate between domestic and international politics and help define which policy proposals qualify as viable in different countries. From a policy perspective, this suggests that the global trajectory of SG depends disproportionately on developments in the US.

Australia's path to net zero emissions must include both emissions reduction and removal of greenhouse gases from the atmosphere. Australia's large landmass and expansive marine estates provide significant opportunities for implementing these negative emissions technologies ('NETs'). Significant further legal innovation will be needed to facilitate NETs crediting and adapt existing environmental, health and safety legislation to this large-scale challenge. As a starting point, this article surveys the current state of Australian law and identifies priority areas for developing a legal framework to facilitate responsible research and development of NETs in Australia. It shows that the enormous scale of greenhouse gas removal requires: a market for NETs credits administered to ensure the legitimacy of crediting practices; special arrangements to facilitate research and development; technology-specific law reform targeting the most promising technologies; and regulatory coordination to ensure that environmental and social risks are adequately managed.

Despite lying outside the Antarctic Treaty area, the longstanding sovereignty dispute between Argentina and the United Kingdom over the Falklands/Malvinas, South Georgias, and the South Sandwich Islands (collectively known as the 'Question of Falklands/Malvinas') has significant implications for Antarctic governance. The South Georgias and South Sandwich Islands are within the CCAMLR Area and sites of significant fishing interest. Over the last four decades, CCAMLR has been able to avoid any confrontation between Argentina and the UK over regulation of fishing activities in waters surrounding these archipelagos. But at the 2021 CCAMLR meeting, Russia controversially blocked renewal of an existing conservation measure for international management of fishing for Patagonian toothfish in waters surrounding the South Georgias. Under the CCALMR regime, a provision known as the 'Chairman's Statement' allows member states to use national law to regulate fishing in waters surrounding islands within the CCAMLR Area over which state sovereignty is recognised by all Contracting Parties. However, there are differing interpretations on whether the Chairman's Statement allows a CCAMLR state to unilaterally use national law to allow fishing in waters surrounding islands which are under territorial dispute. While CCAMLR has so far avoided addressing this issue, as third parties' interests are involved, it will likely need to take a more active role in the near future. This article therefore assesses the serious challenges this issue raises for CCAMLR and the wider ATS and concludes by presenting paths that the Antarctic community could explore to reduce the present tensions.

As Patricia Birnie cautiously and prophetically put it in the inaugural issue of this journal (INEA 1, January 2001, p. 74), “we do not know whether States and the tentative regimes they have so far established can withstand the pressures of globalization of trade and degradation and over-exploitation generated by advances in technologies for locating, fertilizing, harvesting, processing and modifying natural resources and biodiversity. This is truly terra incognita in which such seeds of destruction may already be implanted.” Among the 600 or so papers and reviews published in INEA from 2001 to 2020, more than 70 deal wholly or partly with legal aspects of environmental problems and the international dimensions of environmental justice. While the main focus of INEA has been on issues of public international (inter-state) law , there have also been important inputs drawn from comparative legal analysis (of national legislation and judicial decisions) and from “transnational administrative law” that influence the effectiveness of multilateral treaties and their associated international institutions. Novel concepts and practices emerging from the environmental field (such as recourse to a range of “soft law” principles; flexible delegated standard-setting in the face of global change; and equitable differentiation of compliance duties) have inspired developments in related areas of contemporary international law-making and law-applying. At the same time, the very proliferation of multilateral and bilateral environmental instruments raised new questions and expressions of alarm over “treaty congestion” and “fragmentation” within the international law system. It is not the intention of this paper to explore the general interaction of international environmental law with neighboring disciplines such as international economic law or human rights law, but simply to record the “seismographic” impact of INEA on legal-intellectual discourse over these past two decades. To some extent, the role of the Journal in identifying both new prospects and new risks in this field could indeed be likened to that of a “canary in the coal-mine.” The lessons so learnt may thus offer new insights to help in averting the destruction which Birnie visualized, and to advance inter-generationally and intra- generationally shared values of environmental justice.

Antarctic territorial claims are important for understanding the history and future possibilities of the Antarctic region. Although the 1959 Antarctic Treaty put on hold arguments about territorial claims over the continent, these claims still play a role in shaping the Antarctic Treaty System. To understand these disagreements, it is important to consider the legal basis of the respective claims. One of the key disagreements is between the United Kingdom and Argentina, which have overlapping claims to areas of West Antarctica. European states have generally assumed that the whole of the Antarctic continent was terra nullius when the UK first claimed a part of West Antarctica in 1908. However, Argentina claims that it inherited part of the 'South American Antarctic' from Spain in the early 19th century and has effectively exercised its rights derived from that title. On the other side of the continent, areas of East Antarctica were claimed for the British Commonwealth and later transferred to Australia. The UK and Australia recognise each other's claims. The existing analysis of Antarctic law has not properly considered whether any future outcome of the territorial dispute between the UK and Argentina might legally impact the Australian claims in East Antarctica. This article, therefore, considers the legal basis of the Argentine and Australian claims. We conclude that regardless of any future outcome of the Argentinian-British territorial dispute, there is no overt legal conflict between the Argentinian and Australian claims to Antarctic territory; they may both legally co-exist.

International law provides a system of legal order for the conduct of international relations. Within this system, states may constitute regional legal regimes in a continuous geographical area to address their own regional problems. In Antarctica, states active in the region have developed a sui generis regional legal regime (conceptualised here as ‘Antarctic Law’) to address problems of the Antarctic. During most of the twentieth century, Antarctic Law played a central role in understanding human interaction within, and international ordering of, the Antarctic region. However, over the last two decades, understanding the importance of the legal and regional nature of Antarctic law has become less prominent. Instead, Antarctic scholarship (including legal analysis) has moved towards a universalist perspective, interdisciplinary scholarship and critical approaches. We argue these approaches have under-appreciated the importance of the legal ordering of the region. New challenges within the region will require responses that draw on this regional legal ordering. This paper therefore aims to be a first step towards rediscovering the importance of the concept of ‘Antarctic Law’ as a regional and legal regime with a key role in providing successful international order within the Antarctic region to meet the challenges of the early twenty-first century.

The limits of predictionPrediction, evidence-basedlimits of pose a critical riskRisk for any organisation making long-range decisions about its strategyStrategy and investments. The accuracy of our forecasts degrades progressively due to the combined effects of complexity andUncertainty uncertaintyUncertaintyTUNA conditions, compounded by the passage of timeScenariospassage of time. Scenarios become useful in the zone beyond the limits of standard prediction. However, we question whether it is really the case that scenarios must only start where prediction ends. Do most organisations that invest in scenario planningScenario, ‘core team’planning have no expectation that the scenarios created will provide a credible picture of what the futureFutures might be like? Instead, we view scenarios as anticipatory systems with a distinctive type of predictive model, where prediction is not based on probability, but plausibility. The zone of plausibilityZone of plausibility is a space in which scenarios provide evidence-based, broad-brush, but targeted, prediction. We contend that other objectives for scenarios, (such as futuresFutures consciousness, or re-perception) are necessary but secondary to scenarios’ predictive work in the zone of plausibilityZone of plausibility. Importantly, we argue that if we abandon hope that our scenarios will provide a constrained form of prediction, then we fail to harness the potential that scenarios can offer—when they are plausible, rigorous, and robust.

Australia’s plans to build a 2.7 km airstrip and other infrastructure in the ice-free Vestfold Hills near its Davis Station in East Antarctica have been heavily criticized, primarily on environmental grounds. The aerodrome, which Australia contends would improve scientific access to the continent and facilitate search and rescue operations, could also have an array of geopolitical implications. Antarctic legal expert Jeffrey McGee, an associate professor at the University of Tasmania in Hobart who has come out in support of the project, recently co-authored a report for the Australian Strategic Policy Institute, All-weather aerodrome in Antarctica would be a gamechanger for Australia. Dr. McGee joins the podcast to explain the strategic rationale and current status of the aerodrome and why he believes, if the plans go forward, it would not only benefit Australia but also other Antarctic stakeholders.

In 2018, the international community began formal intergovernmental negotiations over a new legally binding instrument for the protection of marine biodiversity of areas beyond national jurisdiction. Protecting marine biodiversity is imperative for a sustainable future, and all the different organizations and agreements will have to work together to achieve this common goal. One of the first key principles to be agreed was to "not undermine" the existing legal instruments or mandates of regional and sectoral marine governance organizations. While fisheries are not being discussed during the negotiations, a marine biodiversity agreement is likely to still impact regional fisheries management organizations (RFMOs), due to overlapping areas of interest. This article aims to firstly, assess the potential constraints posed by the commitment to "not undermine"; secondly, consider how aspects of the biodiversity agreement, such as area-based management and environmental impact assessments, might enhance RFMOs; and thirdly, suggest meaningful ways to ensure cooperation between RFMOs and the marine biodiversity agreement.

From our review of scenario objectives, approaches, and techniques, we suggest that scenario methods can be grouped under one or more of seven broad approaches: deductive, inductive, quantitative, hybrid, integrated, scoping, and engagement. Each has its strengths and weaknesses. We conclude that no single scenario approach can match the scale and complexity of Antarctic geopolitics. For that reason, we recommend that a scenario process employ a judicious blend of several approaches. For this book, we focus on one technique, the standard intuitive logics ‘2 × 2’ matrix, commonly deployed in geopolitical scenarios. We unpack it with a worked example and encounter some difficulties applying it to the field of Antarctic geopolitics. This leads us to propose some modifications, which may be useful for scenarios in other fields. Importantly, ‘practical’ decisions about scoping and framing of scenarios are shaped, in important ways, by the assumptions and values we hold. Which issues are in? Which are out? How are issues framed? Whose voices are heard, and whose are excluded? What types of data do we admit? How do we handle complexity? What expertise do we need? Decisions about scenario process are not the objective, technical considerations they are often perceived to be.

Ocean governance is complex and influenced by multiple drivers and actors with different worldviews and goals. While governance encompasses many elements, in this paper we focus on the processes that operate within and between states, civil society and local communities, and the market, including industry. Specifically, in this paper, we address the question of how to move towards more sustainable ocean governance aligning with the sustainable development goals (SDGs) and the UN Ocean Decade. We address three major risks to oceans that arise from governance-related issues: (1) the impacts of the overexploitation of marine resources; (2) inequitable distribution of access to and benefits from marine ecosystem services, and (3) inadequate or inappropriate adaptation to changing ocean conditions. The SDGs have been used as an underlying framework to develop these risks. We identify five drivers that may determine how ocean governance evolves, namely formal rules and institutions, evidence and knowledge-based decision-making, legitimacy of decision-making institutions, stakeholder engagement and participation, and empowering communities. These drivers were used to define two alternative futures by 2030: (a) ‘Business as Usual’—a continuation of current trajectories and (b) ‘More Sustainable Future’—optimistic, transformational, but technically achievable. We then identify what actions, as structured processes, can reduce the three major governance-related risks and lead to the More Sustainable Future. These actions relate to the process of co-creation and implementation of improved, comprehensive, and integrated management plans, enhancement of decision-making processes, and better anticipation and consideration of ambiguity and uncertainty.

In this chapter, weAntarcticamilitarisation build on the work of previous chapters to develop five plausible scenarios on Antarctic militarisationAntarcticamilitarisation, using the deductive approach and the IL 2 × 2IL 2x2 technique. Our time horizon is around a decade into the futureFutures. The ‘scenario standpoint’ we adopt is that of states whose policies and actions seek to preserve and enhance the current rules and norms of the ATS—including promotion of the peaceful use of Antarctica and the Southern Ocean. Our first four scenarios are titled Splendid Isolation, QuarantineQuarantine scenario, Stealth, and Cold War IICold War II (scenario). Our fifth scenario scenario is Pressures Managed—a new medium option. This is designed to provide us with some evidence-based, targeted, broad-brush prediction, without suggesting this outcome is more probable. From these five narratives, we offer a set of policy-relevant recommendations. If the non-militarisationAntarcticanon-militarisation of Antarctica is to be preserved, two suggestions stand out. The first is that like-minded states should resist moves to reinterpret what constitutes ‘military activity’ in Antarctica to a lesser standard. The second is that the ATS should review its complianceCompliance and inspection regimesCompliance and inspection regimes, to better account for contemporary military technologies.

In this chapter, we explore how the scenarios constructed in Chap. 8 help us think about Antarctic geopolitics, conceived as the intersection between power, authority, and space, in rivalry between states. We suggest that viewing Antarctic geopolitics through this lens can assist in closing some important conceptual gaps in international law and institutionalist perspectives on Antarctic governance. We examine the intersections between spatial ordering, authority, and power in the subtle rivalry between states in Antarctica and the Southern Ocean. Our scenarios illustrate how projection of power may influence the future of the ATS—both globally, from great power competition, and regionally, from simmering rivalries in the Indo-Pacific and South Atlantic. We suggest that the concept of balance of power might usefully be viewed not simply as an adversarial relationship, but also in associational terms, with its potential for founding a just equilibrium between states. In turn, this just equilibrium can enliven the authority of enabling institutions (such as the ATS) and international law. We also highlight how spatial ordering of areas in, below and above Antarctica is subject to significant tensions due to ambiguities in interaction between the Law of the Sea Convention, the Antarctic Treaty, and treaties governing outer space.

Anthropogenic climate change has warmed the planet to over 1°C above pre-industrial levels. The biophysical and social impacts of this warming are taking hold, with sea-level rise, melting of polar ice, more extreme weather events, drought, and wildfire. Solar radiation management (SRM) technologies are a set of ideas for increasing the reflectivity of the earth at various scales to offset the effects of anthropogenic climate change. The most ambitious SRM idea involves injecting aerosols into the atmosphere to cool the planet on a global scale. However, regional-scale SRM ideas are also being investigated to lessen climate impacts at regional and local scales. International governance of SRM research and development is a key issue for managing risk and building social license for these technologies. Despite this, there has been very limited international legal and institutional development on SRM. It may therefore be better to start working with existing rules and institutions of international law than wait for significant new treaty development to govern the issue. This article examines the potential of the ENMOD Convention - an overlooked Cold War arms control treaty on the use of environmental modification technologies - to contribute to international governance of SRM.

Trajectory and metadata files from a Southern Ocean surface particle release experiment using Connectivity Modeling System (Paris et al. 2013, https://github.com/beatrixparis/connectivity-modeling-system) run offline in the MOM01 model (Stewart et al., 2017; Spence et al., 2017; Morrison et al., 2020), a global 0.1° ocean sea-ice model, based on version 5 of the Modular Ocean Model (MOM) code (mom-ocean.github.io) (Griffies, 2012). Here particle trajectories are are split into 28 netcdf files (numbered traj_file_01.nc through traj_file_28.nc), and uploaded altogether as a single .tar.gz compressed file. Metadata files are also uploaded containing information on the CMS setup and release locations. Netcdf files contain particle trajectory positions, along with temperature, salinity, status in or out of the mixed layer, release date, and particle exit status (see CMS user guide for details on trajectory files). Other CMS setup files included in each release directory are nest_1.nml, runconf.list, ibm.list, and releaseFile_matchtransport. These input files contain information needed to reproduce the experiment using the MOM01 model output, and are explained in detail in the CMS user guide. Citation of associated paper: Bach, L., V. Tamsitt, K. Baldry, J. McGee, E. Laurenceau-Cornec, R. Strzepek, Y. Xie, P. W. Boyd, 2021. Holistic re-evaluation of Southern Ocean Iron Fertilization for atmospheric CO2 removal, submitted References: Griffies, S. M. (2012). Elements of the modular ocean model (MOM). GFDL Ocean Group Tech. Rep, 7(620), 47. Morrison, A. K., Hogg, A. M., England, M. H., & Spence, P. (2020). Warm Circumpolar Deep Water transport towards Antarctic driven by local dense water export in canyons. Science Advances, 6(18), eaav2516. Paris, C. B., Helgers, J., van Sebille, E., & Srinivasan, A. (2013). Connectivity Modeling System: A probabilistic modeling tool for the multi-scale tracking of biotic and abiotic variability in the ocean. Environmental Modelling and Software, 42, 47-54. Spence, P., Holmes, R. M., Hogg, A. M., Gries, S. M., Stewart, K. D., & England, M. H. (2017). Localized rapid warming of West Antarctic subsurface waters by remote winds. Nature Climate Change, 7(8), 595. Stewart, K., Hogg, A. M., Gries, S., Heerdegen, A., Ward, M., Spence, P., & England, M. H. (2017). Vertical resolution of baroclinic modes in global ocean models. Ocean Modelling, 113, 50-65.