ALBERT

Description: Drought risk threatens pastoralism in rangelands, which are already under strain from climatic and socioeconomic changes. We examine the future drought risk (2031–2060 and 2071–2100) to rangeland productivity across Eurasia (West, Central, and East Asia) using a well-tested process-based ecosystem model and projections of five climate models under three shared socioeconomic pathway (SSP) scenarios of low (SSP1−2.6), medium (SSP3−7.0), and high (SSP5−8.5) warming relative to 1985–2014. We employ a probabilistic approach, with risk defined as the expected productivity loss induced by the probability of hazardous droughts (determined by a precipitation-based index) and vulnerability (the response of rangeland productivity to hazardous droughts). Drought risk and vulnerability are projected to increase in magnitude and area across Eurasian rangelands, with greater increases in 2071–2100 under the medium and high warming scenarios than in 2031–2060. Increasing risk in West Asia is caused by longer and more intense droughts and vulnerability, whereas higher risk in Central and East Asia is mainly associated with increased vulnerability, indicating overall risk is higher where vulnerability increases. These findings suggest that future droughts may exacerbate livestock feed shortages and negatively impact pastoralism. The results have practical implications for rangeland management that should be adapted to the ecological and socioeconomic contexts of the different countries in the region. Existing traditional ecological knowledge can be promoted to adapt to drought risk and embedded in a wider set of adaptation measures involving management improvements, social transformations, capacity building, and policy reforms addressing multiple stakeholders.

Description: The decarbonization of India's economy will have different effects across income groups. As India is in the middle of the transformation process from an agriculture-based economy towards an industry- and service-based economy, called economic structural change, the extent of income distribution across households strongly depends also on the speed of economic transformation. While a number of recent studies have analyzed the distributional effects of carbon pricing, the specific role of structural change across sectors has not been in the focus of the related literature. Our study contrasts distributional effects from climate policy with distributional effects from structural change in India and asks how far carbon pricing supports or hinders structural change and development. We develop and apply a comprehensive model framework that combines economic growth and international trade dynamics related to structural change with detailed household income and expenditure data for India. Our study shows that changes in income and inequality due to carbon pricing vary with the changes in the sectoral structure of economies. Our results indicate that carbon pricing tends to delay economic structural change by retarding the reallocation of economic activities from the agricultural sector to the manufacturing sector. Furthermore, the results emphasize that the increase in inequality due to structural change is substantially stronger than due to carbon pricing. Consequently, socially sensitive policies supporting the process of structural transformation appear to be more important for poor households than lowering climate policy ambitions.

Description: "There are no scientifically justified obstacles to protecting biodiversity in all its beauty and diversity. There are only six years left to achieve the biodiversity targets by 2030. We must work together now to get there in time." In the 10 Must Knows from Biodiversity Science 2024, 64 scientists have further developed their well-founded and diverse findings and recommendations from the 10MustKnows22. The content of the ten selected key areas of the Earth-human system is supplemented by relevant publications from 2022 and 2023 and linked to the 23 global goals of the Kunming-Montreal Global Biodiversity Framework (GBF) adopted in December 2022. The authors are aware that the next six years until 2030 are essential for achieving an ecologically sustainable and socially just life on our planet in the medium and long term. With the 10MustKnows24, they want to actively contribute to accelerating the socio-ecological transformation by providing scientifically sound recommendations for politics and society.

Description: Non-traditional and transnational actors have become essential for environmental and climate change governance. One of these actors, the Climate and Clean Air Coalition (CCAC), has taken over a lead role in the governance of SLCPs. Since 2012, the CCAC has been pushing for an increased political dialogue on the one hand, and fostering technical expertise, projects, and a knowledge network on the other hand. This voluntary alliance is an interesting research subject because it brings together a mix of over 150 governmental, intergovernmental, NGO, and scientific members, who closely work on reducing global near term-warming as well as improving air quality, health, and further aspects of sustainable development. This chapter focuses on the CCAC’s role in the international policy landscape and on what it can contribute to SLCP governance. It describes the CCAC’s structure, modus of operation, and activities, and then scrutinizes its potential and challenges for SLCP governance. Furthermore, this text seeks to provide a perspective on the CCAC in the global climate and environmental policy landscape.

Description: Hydrological extremes, such as droughts and floods, can trigger a complex web of compound and cascading impacts (CCI) due to interdependencies between coupled natural and social systems. However, current decision-making processes typically only consider one impact and disaster event at a time, ignoring causal chains, feedback loops, and conditional dependencies between impacts. Analyses capturing these complex patterns across space and time are thus needed to inform effective adaptation planning. This perspective paper aims to bridge this critical gap by presenting methods for assessing the dynamics of the multi-sector CCI of hydrological extremes. We discuss existing challenges, good practices, and potential ways forward. Rather than pursuing a single methodological approach, we advocate for methodological pluralism. We see complementary or even convergent roles for analyses based on quantitative (e.g., data-mining, systems modeling) and qualitative methods (e.g., mental models, qualitative storylines). The data-driven and knowledge-driven methods provided here can serve as a useful starting point for understanding the dynamics of both high-frequency CCI and low-likelihood but high-impact CCI. With this perspective, we hope to foster research on CCI to improve the development of adaptation strategies for reducing the risk of hydrological extremes.

Description: Net-zero energy system configurations can be met in numerous ways, implying diverse economic effects. However, what is usually ignored in techno-economic and economy-wide analysis are the distinct social-political drivers and barriers, which might constrain certain elements of future energy systems. We thus apply a model ensemble that defines social-political storylines which constrain feasible net-zero configurations of the European energy system. Using these configurations in a macroeconomic general equilibrium model allows us to explore economy-wide effects and ultimately the cost-effectiveness of different systems. We find that social-political storylines provide valuable boundary conditions for feasible net-zero designs of the energy system and that the costliest energy sector configuration in fact leads to the highest European-wide welfare levels. This result originates in indirect effects, particularly positive employment effects, covered by the macroeconomic model. However, adverse public budget effects on the transition to net-zero energy may limit the willingness of policymakers who focus on shorter time-horizons to foster such a development. Our results highlight the relevance of considering the interaction of energy system-changes with labor, emission allowance and capital markets, as well as considering long-term perspectives.

Description: The Corona pandemic was one of the most challenging political events of the last decades in Europe in which many important political issues had to be decided within a very short space of time. Deliberative, sortition-based formats offer new approaches to strengthen democracy in times of crisis but have so far mainly been used for fundamental issues that have been under discussion for a long time. In Germany, four Corona Citizens’ Councils were organized at different levels to deal with the highly dynamic pandemic situation. The first was on local level and took place in the city of Augsburg, the next and most prominent one in the state of Baden-Wurttemberg (‘Bürgerforum Corona’), being held monthly over a period of 13 months. Another one was organized in the state of Saxony, a fourth one in Thuringia. The article examines the background, the methodological quality and the outcomes of three Corona Citizens’ Councils in Germany. The article compares the three Citizens’ Councils and draws conclusions about the crisis-management capacities of deliberative formats in dealing with pressing political issues in highly dynamic situations.

Description: Background This article asks the following question: how well are coal regions, affected by phase-out plans, represented in mediating commissions, to what extent do local communities participate in the decision-making process and how are the political negotiations perceived by the communities? We look at the case of the German lignite phase-out from a procedural justice perspective. Informed by literature on sociotechnical decline and procedural justice in energy transitions, we focus first on aspects of representation, participation and recognition within the German Commission on Growth, Structural Change and Employment (“Coal Commission”). Second, we analyze how to exnovate coal in two regions closely tied to the coal- and lignite-based energy history in Germany: Lusatia and the Rhenish Mining District. Results Based on interview series in both regions, we connect insights from local communities with strategies for structural change and participation programs in the regions. We find significant differences between the two regions, which is primarily an effect of the challenging historical experiences in Lusatia. Participation within existing arrangements is not sufficient to solve these problems; they require a comprehensive strategy for the future of the regions. Conclusions We conclude that the first phase-out process was a lost opportunity to initiate a community-inclusive sustainable transition process. As the phase-out process is not yet concluded, additional efforts and new strategies are needed to resolve the wicked problem of lignite phase-out.

Description: The transport sector and especially private cars pose environmental, economic, and social challenges. For this reason, cargo bikes and shared mobility are considered viable alternatives for road transport. In order to understand the potential and barriers of alternative transport modes, it is essential to analyze underlying motives. Moreover, comparing sustainable alternatives (such as public transport) to cars in terms of motives has been established as a research approach (Steg, 2003). Despite increasing interest in cargo bikes and cargo bike sharing, research on this topic is relatively rare. Particularly, there exists a lack of research addressing the impact of cargo bike sharing on car ownership. Against this background, this study quantifies the car ownership reduction effect of cargo bike sharing. In addition, it is investigated how cargo bikes differ from cars with regard to the underlying motives of users which also helps understanding potential barriers. To answer these research questions, this study is based on a large-scale survey with n = 2,590 cargo bike sharing users. The results imply that cargo bike sharing has a notable impact on car ownership. In general, cargo bikes are rated superior in regard to affective, symbolic, and environmental motives as well as on flexibility and price. However, discrepancies to cars do exist in terms of other instrumental aspects (traffic safety, travel speed, comfort, weather-independence). Notably, users who reduced car ownership tend to rate cargo bikes superior compared to car-dependent users. The results imply that cargo bikes can play a marked role in reducing car dependency. Improving infrastructure and cargo bike technology as well as stimulating favorable social norms for cargo bikes have been identified as beneficial conditions that could help to leverage this potential.

Description: In sustainability transitions research, the deliberate destabilisation of socio-technical regimes is increasingly recognised as a central intervention point. Absent, however, are granular approaches for assessing whether regime destabilisation actually occurs in processes of systemic change. We propose to assess regime destabilisation through shifts in the institutionalisation of field logics. Methodologically, we employ Socio-Technical Configuration Analysis to map changes over time in the composition and alignment of institutional and technological concepts embedded in sectoral policy. Empirically, we assess the extent to which post-Brexit agricultural policy reform in the United Kingdom marks the destabilisation of an unsustainable regime. Assessing legislative debate transcripts, we find that the previously dominant regime is only partly destabilised, as pre-existing development trajectories along established configurations of field logics, policy goals and instruments remain. These findings support the validity of our conceptual approach. Moreover, they nuance expectations about large-scale policy change as windows of opportunity for regime shifts.

Description: Where annual layers are found in stalagmites, these can be used to provide insights into palaeoclimate. Sebastian F.M. Breitenbach and Norbert Marwan present a low-cost and high-resolution method for acquisition and analysis of greyscale data from speleothems by means of the free open-source ImageJ software.

Description: Climate models are vital for understanding and projecting global climate change and its associated impacts. However, these models suffer from biases that limit their accuracy in historical simulations and the trustworthiness of future projections. Addressing these challenges requires addressing internal variability, hindering the direct alignment between model simulations and observations, and thwarting conventional supervised learning methods. Here, we employ an unsupervised Cycle-consistent Generative Adversarial Network (CycleGAN), to correct daily Sea Surface Temperature (SST) simulations from the Community Earth System Model 2 (CESM2). Our results reveal that the CycleGAN not only corrects climatological biases but also improves the simulation of major dynamic modes including the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole mode, as well as SST extremes. Notably, it substantially corrects climatological SST biases, decreasing the globally averaged Root-Mean-Square Error (RMSE) by 58%. Intriguingly, the CycleGAN effectively addresses the well-known excessive westward bias in ENSO SST anomalies, a common issue in climate models that traditional methods, like quantile mapping, struggle to rectify. Additionally, it substantially improves the simulation of SST extremes, raising the pattern correlation coefficient (PCC) from 0.56 to 0.88 and lowering the RMSE from 0.5 to 0.32. This enhancement is attributed to better representations of interannual, intraseasonal, and synoptic scales variabilities. Our study offers a novel approach to correct global SST simulations and underscores its effectiveness across different time scales and primary dynamical modes.

Description: We utilize a global warming level (GWL) lens to evaluate global and regional patterns of agricultural impacts as global surface temperature increases, providing a unique perspective on the experience of stakeholders with continued warming in the 21st century. We analyze crop productivity outputs from 11 crop models simulating 5 climate models under 3 emissions scenarios across 4 crops within the AgMIP/ISIMIP Phase 3 ensemble. We categorize regional productivity changes (without adaptation) into 9 characteristic climate change response patterns, identifying consistent increases and decreases as well as non-linear (peak or dip) responses indicative of inflection points reversing trends as GWLs increase. Many maize regions and pockets of wheat, rice and soybean show peak decrease patterns where initial increases may lull stakeholders into complacency or maladaptation before productivity shifts to losses at higher GWLs. Although the GWL perspective has proven useful in connecting diverse climate models and emissions scenarios, we identify multiple pitfalls that recommend proceeding with caution when applying this approach to climate impacts. Chief among these is that carbon dioxide (CO2) concentrations at any GWL depend on a climate model's transient climate response (TCR). Higher CO2 concentrations generally benefit crop productivity, so this leads to more pessimistic agricultural projections for so-called “hot” models and can skew multi-model ensemble results as models with high TCR are disproportionately likely to reach higher GWLs. While there are strong connections between many climatic impact-drivers and GWLs, vulnerability and exposure components of food system risk are strongly dependent on development pathways.

Description: Chapter 6 presents an introduction and sections on: earth system analysis from a nonlinear physics perspective; physics fields with relevance for energy technologies; towards green cities: the role of transport electrification; environmental safety; understanding and predicting space weather

Description: Residential buildings directly contribute 11% to local greenhouse gas emissions and up to 40% of total emissions when accounting for energy use for electricity generation. In order to achieve the climate targets in line with the Federal Climate Protection Act, increased ambition level of climate policy instruments is required in this sector. In this research, we are interested in the governance of this sector and the role of evaluation: the government-mandated processes used to evaluate policy in terms of the actors, organisations and ministries involved in executing and coordinating these processes; and the metrics and methods as well as the scope and granularity of evaluations.

Description: Real-world labs make the mobility transition tangible for residents. However, these experiences are not always positive, and often local conflicts arise. Based on in-depth interviews, the authors show that perceived procedural unfairness as well as the redistribution of space are the main drivers of a sceptical attitude towards redesign projects. Real-world labs (RwLs) are often used to explore and foster the mobility transition. Many RwLs dealing with mobility transition temporarily reallocate public spaces from motorized to active transport or to leisure activities. While some residents accept and enjoy the changes, others react with scepticism, rejection, or protest. This can lead to conflicts. Controversial perceptions and conflicts among residents make a permanent redesign rather challenging for the administration and the politicians. In this paper the authors investigate the related conflict types and counterarguments by studying the case of a temporary redesign of an intersection in Berlin. Based on in-depth interviews, they untangle procedural, distributional, and identity conflicts which might underlie the critical and ambivalent perceptions of residents. An abundance of conflict issues pertaining to procedural and distributional conflicts are revealed and emphasize the role of the RwL process.

Description: In order to avoid dangerous climate change and to satisfy the global energy needs energy systems have to change. Hopes are especially high in countries of the Global South for the low-carbon transition to propel sustainable development. Yet, while the energy transition provides opportunities, it also raises questions on how to avoid new global inequalities. This study presents the first quantitative approach to measure the extent to which the energy transitions in the Global South incorporate elements of energy justice. In doing so, this study builds on a rich literature on energy justice that differentiates between distributional, recognition, and procedural justice, thus taking into account social and development objectives such as affordability and accessibility of energy, the inclusion of marginalised parts of society, as well as broader community involvement and participation. Though much important conceptual and qualitative work has been done, what has been lacking so far is a quantitative measure of the degree to which the energy transition lives up to the imperative of energy justice, going beyond the much-studied Global North. The proposed energy justice index is designed and applied to select countries from Southeast Asia (Malaysia), sub-Saharan Africa (Kenya), the MENA region (Jordan), and Latin America (Chile). The index stands the test of the empirical application and demonstrates significant variation between countries along the different dimensions of energy justice. The study also emphasizes the importance of further testing and of improving data quality for informed policy making of energy justice issues in the Global South.

Description: Net zero targets have rapidly become the guiding principle of climate policy, implying the use of carbon dioxide removal (CDR) to compensate for residual emissions. At the same time, the extent of (future) residual emissions and their distribution between economic sectors and activities has so far received little attention from a social science perspective. This constitutes a research gap as the distribution of residual emissions and corresponding amounts of required CDR is likely to become highly contested in the political economy of low-carbon transformation. Here, we investigate what function CDR performs from the perspective of sectors considered to account for a large proportion of future residual emissions (cement, steel, chemicals, and aviation) as well as the oil and gas industry in the EU. We also explore whether they claim residual emissions to be compensated for outside of the sector, whether they quantify these claims and how they justify them. Relying on interpretative and qualitative analysis, we use decarbonization or net zero roadmaps published by the major sector-level European trade associations as well as their statements and public consultation submissions in reaction to policy initiatives by the EU to mobilize CDR. Our findings indicate that while CDR technologies perform an important abstract function for reaching net zero in the roadmaps, the extent of residual emissions and responsibilities for delivering corresponding levels of negative emissions remain largely unspecified. This risks eliding pending distributional conflicts over residual emissions which may intersect with conflicts over diverging technological transition pathways advocated by the associations.

Description: The Paris Agreement requires countries to break away from carbon lock-in, a particular challenge for traditional oil and gas producers. How can these countries overcome path-dependencies to shift from a fossil fuel heavy system to one relying on renewable energy? Malaysia epitomizes this challenge: the country is the second-largest oil producer in Southeast Asia whilst the fossil fuel energy sector takes up nearly 80 % of total greenhouse gas (GHG) emissions, with coal energy occupying the largest share. To identify leverage points of energy transitions, we model the structural components influencing the Malaysian energy system and assess the dynamics of interrelating factors. Based on stakeholders' input, we identify main factors influencing Malaysia's energy transition, explore their interactions, and use Cross Impact Balances (CIB) to create scenarios. Our analysis reveals the need to simultaneously disperse the centralized political power to a more diverse set of actors whilst introducing green growth recovery packages to break the carbon lock-in. Whilst focused on Malaysia, the findings contribute more generally to our understanding how fossil fuel reliant emerging economies can break path-dependencies inhibiting the clean energy transition.

Description: The topic of greenhouse gas emissions embodied in products is gaining in prominence and the possibilities for measuring and verifying them are improving. This provides fertile ground for those who demand that climate policy should address such embodied emissions. There are different design options for policies targeting embodied emissions. Such differences affect which groups can be mobilized in their favour. This paper shows that procurement standards which target intermediate products can mobilize the support of relatively low carbon producers of high carbon materials, while product standards which target final products can mobilize the support of producers of relatively low carbon materials and knowledge-intensive service providers.

Description: L’alimentation est à la fois un levier central pour engager la transition socio-écologique et un theme quotidien tangible pour chaque citoyen.ne. En Allemagne comme en France, quelques collectivités territoriales engagent des mesures innovantes pour promouvoir une alimentation locale et durable. Le Forum pour l’avenir franco-allemand s’est penché sur les expériences de certaines de ces collectivités et a facilité le dialogue entre elles durant plusieurs mois afin de comprendre quelles politiques nationales peuvent soutenir de telles initiatives locales. En associant des expert.e.s issus de la sphère scientifique, de l’administration et de la société civile, il a recommandé de « Donner la priorité au développement de systèmes alimentaires locaux et durables » avec cinq propositions d’action concrètes aux gouvernements français et allemand. Cette étude présente les initiatives françaises et allemandes ayant nourri les propositions d’action du Forum pour l’avenir.

Description: Food and food policy is central to social-ecological transformation. It is also an everyday issue that is easy to communicate to citizens. Municipalities in Germany and France have recognized the potential of innovative local food policies and have developed and tested innovative approaches to transforming local food systems. However, they are encountering structural barriers that cannot be overcome at the municipal level. The Franco-German Forum for the Future has researched the opportunities and obstacles of local nutritional change and brought engaged municipalities from both countries into exchange with each other. Together with experts from academia, public administrations and civil society, it has developed the seven recommendations for the national governments, one of which concerns "Prioritizing the development of local and sustainable food systems" with five proposals for action. This study is intended as a background paper to the Recommendation. With recourse to the concrete example of Mouans-Sartoux and other municipalities in France and Germany, it describes the potentials of a sustainable municipal food policy and provides – from concrete local practice – the background knowledge for each of the five proposals for action.

Description: Germany is known for its ambitious climate policy targets. By 2045, the country seeks to achieve climate neutrality. As an intermediate step, the government has determined emission thresholds for different economic sectors through the year 2030. The industrial sector has so far not been a frontrunner in Germany's emission reduction efforts. Much of the country's success in this context is owed to the successful ramp-up of renewables in the electricity sector. For German industries, this means that they have little time left to undergo a substantial climate-friendly transformation by 2030. But how can this be achieved? This chapter introduces five different building blocks of Germany's climate strategy for its emission-intensive industrial sector: (1) The expansion of renewable energy for electricity production; (2) electrification and energy efficiency improvements; (3) the establishment of a green hydrogen economy; (4) the transformation towards a circular economy; and lastly (5) carbon capture and storage (CCS) and carbon capture and utilization (CCU). In an in-depth case study, the chapter reviews the particular role of CCU as a strategic component, discussing its potential as a climate strategy, its regulatory and legal framework, as well as insights on the broader societal acceptance of this technological approach.

Description: Dataset of recurrence plot bibliography. Scripts to retrieve additional data (paper citations and authors' affiliations) and to perform some statistical bibliometric and bibliographic analysis of the recurrence plot bibliography. Scripts are forPython and MATLAB.

Description: MATLAB scripts and functions used to create spatial recurrence plots to study circular structures in higherdimensional data fields, and to reproduce the figures of M. Riedl, N. Marwan, J. Kurths: Extended generalized recurrence plot quantification of complex circular patterns, European Physical Journal B, 90(58), 1–9 (2017). DOI:10.1140/epjb/e2017-70560-7

Description: A transition to healthy diets like the EAT-Lancet Planetary Health Diet could considerably reduce GHG emissions. However, the specific contributions of dietary shifts for the feasibility of 1.5°C pathways remain unclear. Here, we use the open-source Integrated Assessment Modeling (IAM) framework REMIND-MAgPIE to compare 1.5°C pathways with and without dietary shifts. We find that a flexitarian diet increases the feasibility of the Paris Agreement climate goals in different ways: The reduction of GHG emissions related to dietary shifts, especially methane from ruminant enteric fermentation, increases the 1.5°C-compatible carbon budget. Therefore, dietary shifts allow to achieve the same climate outcome with less carbon dioxide removal (CDR) and less stringent CO2 emission reductions in the energy system, which reduces pressure on GHG prices, energy prices and food expenditures.

Description: Photovoltaics (PV) and wind are the most important energy-conversion technologies for cost-efficient climate change mitigation. To reach international climate goals, the annual PV module production must be expanded to multi-terawatt (TW) scale. Economic and resource restraints demand the implementation of cost-efficient multi-junction technologies, for which perovskite-based tandem technologies are highly promising. In this work, the resource demand of the emerging perovskite PV technology is investigated, considering two factors of supply criticality, namely, mining capacity for minerals and the production capacity for synthetic materials. Overall, the expansion of perovskite PV to a multi-TW scale may not be limited by material supply if certain materials, especially indium, can be replaced. Moreover, organic charge-transport materials face currently unresolved scalability challenges. This study demonstrates that, besides the improvement of efficiency and stability, perovskite PV research and development also need to be guided by sustainable materials choices and design-for-recycling considerations.

Description: Forests, critical components of global ecosystems, face unprecedented challenges due to climate change. This study investigates the influence of functional diversity—as a component of biodiversity—to enhance long-term biomass of European forests in the context of changing climatic conditions. Using the next-generation flexible trait-based vegetation model, LPJmL-FIT, we explored the impact of functional diversity on long-term forest biomass under three different climate change scenarios (video abstract: https://www.pik-potsdam.de/~billing/video/2023/video_abstract_billing_et_al_LPJmLFIT.mp4). Four model set-ups were tested with varying degrees of functional diversity and best-suited functional traits. Our results show that functional diversity positively influences long-term forest biomass, particularly when climate warming is low (RCP2.6). Under these conditions, high-diversity simulations led to an approximately 18.2% increase in biomass compared to low-diversity experiments. However, as climate change intensity increased, the benefits of functional diversity diminished (RCP8.5). A Bayesian multilevel analysis revealed that both full leaf trait diversity and diversity of plant functional types contributed significantly to biomass enhancement under low warming scenarios in our model simulations. Under strong climate change, the presence of a mixture of different functional groups (e.g. summergreen and evergreen broad-leaved trees) was found more beneficial than the diversity of leaf traits within a functional group (e.g. broad-leaved summergreen trees). Ultimately, this research challenges the notion that planting only the most productive and climate-suited trees guarantees the highest future biomass and carbon sequestration. We underscore the importance of high functional diversity and the potential benefits of fostering a mixture of tree functional types to enhance long-term forest biomass in the face of climate change.

Description: The question of how science can become a lever in achieving the Sustainable Development Goals permeates most recent sustainability research. Wide-ranging literature calling for a transformative approach has emerged in recent years. This ‘transformative turn’ is fueled by publications from fields such as sustainability science, social-ecological research, conservation science, sustainability transitions, or sustainability governance studies. However, there is a lack of a shared understanding specifically of what is meant for research to be transformative in this developing discourse around doing science differently to tackle sustainability problems. We aim to advance transformative research for sustainability. We define transformative research and outline six of its characteristics: (1) interventional nature and a theory of change focus; (2) collaborative modes of knowledge production, experimentation and learning; (3) systems thinking literacy and contextualization; (4) reflexivity, normative and inner dimensions; (5) local agency, decolonization, and reshaping power; (6) new quality criteria and rethinking impact. We highlight three tensions between transformative research and traditional paradigms of academic research: (1) process- and output-orientation; (2) accountability toward society and toward science; (3) methodologies rooted in scientific traditions and post-normal methodologies. We conclude with future directions on how academia could reconcile these tensions to support and promote transformative research.

Description: Dominant ways of doing research are not enough to achieve the UN Sustainable Development Goals. The typical response of science to dealing with the current local and global sustainability crises is to produce and accumulate more knowledge. Transformative research seeks to couple knowledge production with co-creating change. This paper defines the transformative way of doing research to pro-actively support society's fight against pressing societal and environmental problems. We present six characteristics of transformative research. We reflect on the challenges related to implementing these characteristics in scientific practice and on how academia can play its part.

Description: Strategies for mitigating climate change today include plans for removing carbon dioxide from the atmosphere through “Negative Emissions Technologies” (NETs). NETs create new opportunities for scientific research, technology development, and the development of financial products, but also new conceptual possibilities, for example of declaring one’s ambition to become “climate neutral.” NETs thus constitute a novel frontier in climate science and politics whose conditions of possibility, characteristics, and consequences can be studied by social scientists and humanists. For environmental sociologists, NETs pose numerous opportunities for engaging with questions around future-making, imaginaries, promises, expertise, markets, infrastructure, justice, publics, and generally, the shape and role of science and technology in a form of social life that is increasingly organized around “planetary” concepts.

Description: CrossGov D2.1 EU and international policy landscape - Mapping EU policies and Green Deal objectives: general observations for policy coherence in the marine domain aims to provide a mapping of the European Green Deal policy landscape relevant to the marine domain and the CrossGov project. It also offers a general introduction into how policy coherence, embedded within the design of (selected) EU policies, supports or impedes progress towards the EGD’s objectives in the marine domain. A total of 36 policies were selected and mapped against five EGD strategies, namely the 2030 Climate Target Plan, the EU Climate Change Adaptation Strategy, the Biodiversity Strategy for 2030, the Zero Pollution Action Plan, and the Sustainable Blue Economy Strategy. These five strategies lay out a total of 25 specific objectives to implement the vision of the EGD, identified as relevant to the marine domain and the focus of the CrossGov project – i.e. climate change, biodiversity loss, and pollution.

Description: The PermaGov Deliverable focuses on exploring the EU policy landscape within the context of the European Green Deal (EGD), structured around four regime complexes: marine life, marine plastics, marine energy, and maritime transport. These complexes provide a framework for analysing the EU's approach to achieving the EGD's vision for sustainable marine governance. This report aims to offer a descriptive overview of marine EU policies relevant to the PermaGov project, focusing on policies identified as relevant to the overarching goals set forth in the EGD. It also considers relevant initiatives at global and regional levels. The marine life regime sees the EU Biodiversity Strategy for 2030 as its overarching strategy, essential for the EGD’s element of preserving and restoring ecosystems and biodiversity. Tackling the challenges of marine waste pollution, the marine plastics regime is guided by the EU Circular Economy Action Plan and the EU Action Plan: Towards Zero Pollution for Air, Water, and Soil, targeting the EGD’s elements of a mobilising industry for a clean and circular economy and a zero-pollution ambition for a toxic-free environment. The marine energy regime is shaped by the European Climate Law and the Offshore Renewable Energy Strategy, which are the overarching instruments that contribute to the EGD’s elements of increase the EU’s climate ambition for 2030 and 2050 and ensure the supply of clean, affordable, and secure energy. Lastly, the maritime transport regime sees the 'Fit for 55' Package and the 'Sustainable and Smart Mobility Strategy' as the two main instruments to achieve the EGD’s elements of increase the EU’s climate ambition for 2030 and 2050 and Accelerating the Shift to Sustainable and Smart Mobility. An additional aspect of this report is an initial screening of institutional barriers through the lens of policy documents. This is intended to be a starting point for the case studies of the PermaGov project, which will be further investigated in more depth later in the project. Institutional barriers are understood as obstacles within the structure and processes of governance systems that hamper decision-making processes and policy implementation. These barriers often arise from established rules, norms, and practices. The report considers the analytical framework developed by Oberlack (2017), focusing on attributes of institutions such as actor eligibility, responsibility, control, social connectivity, conflict, social learning, accountability, temporal and spatial scale, adaptiveness, and formality. These attributes describe the characteristics of how institutions are organised and operate, providing insights into potential challenges in policy design and implementation. The report provides a mapping of instruments relevant to the PermaGov four regime complexes and concludes by identifying potential institutional barriers, underlining the importance of conducting further detailed research in upcoming tasks of the PermaGov projects to effectively address the challenges of sustainable marine governance in line with the EGD’s ambitions.

Description: In this discourse, we present the unveiling of an open-source software package designed to facilitate engagement with the atmospheric model, Aeolus 2.0. This particular iteration stands as a self-contained model of intermediate complexity. The model's dynamical core is underpinned by a multi-layer pseudo-spectral moist-convective Thermal Rotating Shallow Water (mcTRSW) model. The pseudo-spectral problem-solving tasks are handled by the Dedalus algorithm, acknowledged for its spin-weighted spherical harmonics. The model captures the temporal and spatial evolution of vertically integrated potential temperature, thickness, water vapour, precipitation, and the intricate influence of bottom topography. It comprehensively characterizes velocity fields in both the lower and upper troposphere, employing resolutions spanning a spectrum from the smooth to the coarse, enabling the exploration of a wide range of dynamic phenomena with varying levels of detail and precision.

Description: We study the impact of California’s cap-and-trade system on carbon emissions in the electricity and industrial sectors. We use US state-level panel data covering the period 2005–2019 and apply the synthetic control method to construct an optimal counterfactual for per capita emissions in each sector. In our experiment, emissions in the power sector fall below counterfactual emissions by 48%. In the industrial sector, the state’s emissions are 6% higher than those of the synthetic control unit by the end of the observation period. Thus, cap-and-trade failed to deliver decarbonization across both sectors. While the abatement in the power sector was facilitated by complementary policies and driven by a switch from natural gas to renewables, California’s policy mix has disincentivized emission reductions in the industrial sector.

Description: Human activities have had a significant impact on Earth's systems and processes, leading to a transition of Earth's state from the relatively stable Holocene epoch to the Anthropocene. The planetary boundaries framework characterizes major risks of destabilization, particularly in the core dimensions of climate and biosphere change. Land system change, including deforestation and urbanization, alters ecosystems and impacts the water and energy cycle between land surface and atmosphere, while climate change can disrupt the balance of ecosystems and impact vegetation composition and soil carbon pools. These drivers also interact with each other, further exacerbating their impacts. Earth system models have been used recently to illustrate the risks and interacting effects of transgressing selected planetary boundaries, but a detailed analysis is still missing. Here, we study the impacts of long-term transgressions of the climate and land system change boundaries on the Earth system using an Earth system model with an incorporated detailed dynamic vegetation model. In our centennial-scale simulation analysis, we find that transgressing the land system change boundary results in increases in global temperatures and aridity. Furthermore, this transgression is associated with a substantial loss of vegetation carbon, exceeding 200 PgC, in contrast to conditions considered safe. Concurrently, the influence of climate change becomes evident as temperatures surge by 2.7–3.1 °C depending on the region. Notably, carbon dynamics are most profoundly affected within the large carbon reservoirs of the boreal permafrost areas, where carbon emissions peak at 150 PgC. While a restoration scenario to reduce human pressure to meet the planetary boundaries of climate change and land system change proves beneficial for carbon pools and global mean temperature, a transgression of these boundaries could lead to profoundly negative effects on the Earth system and the terrestrial biosphere. Our results suggest that respecting both boundaries is essential for safeguarding Holocene-like planetary conditions that characterize a resilient Earth system and are in accordance with the goals of the Paris Climate Agreement.

Description: The majority of signatories to The United Nations Climate Change Conference in 2021 (COP26) made a declaration to end deforestation by 2030. Here, we quantify future changes in land use and associated CO2 emissions to examine the impact of ending deforestation by 2030 on global land dynamics and emissions using an open-source land-use model. We show that if the COP26 declaration to end deforestation is fully implemented globally, about 167 Mha of deforestation could be avoided until 2050, compared to a baseline scenario which does not have extended forest protection. However, avoided deforestation and associated emissions come at the cost of strongly increased conversion of unprotected non-forested land to agricultural land, while land-use intensification in most regions is similar compared to a baseline scenario. Global initiatives are needed to facilitate a common dialogue on addressing the possible carbon emissions and non-forest leakage effects due to the expedited loss of non-forested land under a policy aimed at halting deforestation by 2030.

Description: As the Earth system is exposed to large anthropogenic interferences, it becomes ever more important to assess the resilience of natural systems, i.e., their ability to recover from natural and human-induced perturbations. Several, often related, measures of resilience have been proposed and applied to modeled and observed data, often by different scientific communities. Focusing on terrestrial ecosystems as a key component of the Earth system, we review methods that can detect large perturbations (temporary excursions from a reference state as well as abrupt shifts to a new reference state) in spatio-temporal datasets, estimate the recovery rate after such perturbations, or assess resilience changes indirectly from stationary time series via indicators of critical slowing down. We present here a sequence of ideal methodological steps in the field of resilience science, and argue how to obtain a consistent and multi-faceted view on ecosystem or climate resilience from Earth observation (EO) data. While EO data offers unique potential to study ecosystem resilience globally at high spatial and temporal scale, we emphasize some important limitations, which are associated with the theoretical assumptions behind diagnostic methods and with the measurement process and pre-processing steps of EO data. The latter class of limitations include gaps in time series, the disparity of scales, and issues arising from aggregating time series from multiple sensors. Based on this assessment, we formulate specific recommendations to the EO community in order to improve the observational basis for ecosystem resilience research.

Description: Global flood impacts have risen in recent decades. While increasing exposure was the dominant driver of surging impacts, counteracting vulnerability reductions have been detected, but were too weak to reverse this trend. To assess the ongoing progress on vulnerability reduction, we combine a recently available dataset of flooded areas derived from satellite imagery for 913 events with four global disaster databases and socio-economic data. Event-specific flood vulnerabilities for assets, fatalities and displacements reveal a lack of progress in reducing global flood vulnerability from 2000—2018. We examine the relationship between vulnerabilities and human development, inequality, flood exposure and local structural characteristics. We find that vulnerability levels are significantly lower in areas with good structural characteristics and significantly higher in low developed areas. However, socio-economic development was insufficient to reduce vulnerabilities over the study period. Nevertheless, the strong correlation between vulnerability and structural characteristics suggests further potential for adaptation through vulnerability reduction.

Description: Simulating the ozone variability at regional scales using chemistry transport models (CTMs) remains a challenge. We designed a multi-model intercomparison to evaluate, for the first time, four regional CTMs on a national scale for Germany. Simulations were conducted with LOTOS-EUROS, REM-CALGRID, COSMO-MUSCAT and WRF-Chem for January 1st to December 31st, 2019, using prescribed emission information. In general, all models show good performance in the operational evaluation with average temporal correlations of MDA8 O3 in the range of 0.77-0.87 and RMSE values between 16.3 mu g m3 and 20.6 mu g m- 3. On average, better models' skill has been observed for rural background stations than for the urban background stations as well as for springtime compared to summertime. Our study confirms that the ensemble mean provides a better model-measurement agreement than individual models. All models capture the larger local photochemical production in summer compared to springtime and observed differences between the urban and the rural background. We introduce a new indicator to evaluate the dynamic response of ozone to temperature. During summertime a large ensemble spread in the ozone sensitivities to temperature is found with (on average) an underestimation of the ozone sensitivity to temperature, which can be linked to a systematic underestimation of mid-level ozone concentrations. During springtime we observed an ozone episode that is not covered by the models which is likely due to deficiencies in the representation of background ozone in the models. We recommend to focus on a diagnostic evaluation aimed at the model descriptions for biogenic emissions and dry deposition as a follow up and to repeat the operational and dynamic analysis for longer timeframes.

Description: Transdisciplinary processes deal with transdisciplinary problems that are (i) complex, (ii) societally relevant, (iii) ill-defined, and (iv) real-world problems which often show a high degree of ambiguity resulting in contested perceptions and evaluations among and between scientists and practitioners. Therefore, they are susceptible to multiple trade-offs. Transdisciplinary processes construct socially robust orientations (SoROs) particularly for sustainable transitioning. The integration of science and practice knowledge on equal footing (1) is considered the core of transdisciplinary processes. Yet other forms of knowledge integration contribute essentially to construct SoROs. Individuals may (2) use different modes of thought; (3) refer to various cultures with diverse value and belief systems; and (4) problems are perceived and prioritized based on roles and interests. Coping with transdisciplinary problems, (5) purposeful differentiation and integration and (6) an integration of evolutionary evolving codes of representing knowledge are necessary. Finally, (7) what systems to integrate requires consensus-building among participating scientists and practitioners. This paper is Part I of a two-part publication. It provides a conceptualization of the different types of knowledge integration. Part II analyzes tasks, challenges, and barriers related to different types of knowledge integration in five transdisciplinary processes which developed SoROs for sensitive subsystems of Germany affected by the irresponsible use of digital data.

Description: Transdisciplinary problems are complex, ill-defined, societal real-world problems with high ambiguity that are contested and require multiple trade-offs. Part I of this paper showed that transdisciplinary processes include seven types of knowledge integration: system (ontological), epistemological, cultural, cognitive, social conflict, evolutionary (levels of representation), and complexity-theory-based types of knowledge integration. The epistemological integration of the different modes of reasoning from science and practice is a unique selling point of the transdisciplinary process. Part II presents five transdisciplinary processes for the responsible use of digital data in different vulnerable/sensitive subsystems of Germany (mobility, health, agriculture, SME, and social media). Between 10 and 18 participants (equally representing science and practice in each group) synchronously constructed socially robust orientations as pillars of a white book. We elaborate that outcomes of a transdisciplinary process can be improved, and barriers diminished by reflecting on which of the seven types of knowledge integration are applied (see Part I). This is done for the six phases of a transdisciplinary process: (1) triggering, (2) initiation, (3) preparation, (4) planning, (5) core, and (6) post-processing. We particularly address researchers and practitioners who seek insights into how the production and integration of knowledge can be improved by transdisciplinary processes.

Description: Introduction Current urban and transport planning practices have significant negative health, environmental, social and economic impacts in most cities. New urban development models and policies are needed to reduce these negative impacts. The Superblock model is one such innovative urban model that can significantly reduce these negative impacts through reshaping public spaces into more diverse uses such as increase in green space, infrastructure supporting social contacts and physical activity, and through prioritization of active mobility and public transport, thereby reducing air pollution, noise and urban heat island effects. This paper reviews key aspects of the Superblock model, its implementation and initial evaluations in Barcelona and the potential international uptake of the model in Europe and globally, focusing on environmental, climate, lifestyle, liveability and health aspects. Methods We used a narrative meta-review approach and PubMed and Google scholar databases were searched using specific terms. Results The implementation of the Super block model in Barcelona is slow, but with initial improvement in, for example, environmental, lifestyle, liveability and health indicators, although not so consistently. When applied on a large scale, the implementation of the Superblock model is not only likely to result in better environmental conditions, health and wellbeing, but can also contribute to the fight against the climate crisis. There is a need for further expansion of the program and further evaluation of its impacts and answers to related concerns, such as environmental equity and gentrification, traffic and related environmental exposure displacement. The implementation of the Superblock model gained a growing international reputation and variations of it are being planned or implemented in cities worldwide. Initial modelling exercises showed that it could be implemented in large parts of many cities. Conclusion The Superblock model is an innovative urban model that addresses environmental, climate, liveability and health concerns in cities. Adapted versions of the Barcelona Superblock model are being implemented in cities around Europe and further implementation, monitoring and evaluation are encouraged. The Superblock model can be considered an important public health intervention that will reduce mortality and morbidity and generate cost savings for health and other sectors.

Description: In academia and political debates, the notions of ‘degrowth’ has gained traction since the dawn of the 21st century. While some uncertainty around its exact definition remains, research on degrowth revolves around the idea of reducing resource and energy throughput as a unifying theme. We employ a mixed-methods design to systematically review the scientific peer-reviewed English literature from 2008 to 2022 that refers to ‘degrowth’ or ‘post-growth’ in title, keywords or abstract (N = 951). We find a lack of concrete distributional and monetary policy proposals in the sample analyzed, and a low overall degree of collaboration among authors in relation to degrowth's age and size. The scientific peer-reviewed literature analyzed can be grouped into seven clusters along two major gradients, one along methodology (qualitative-quantitative) and the other along scale-of-analysis (individual-societal). We conclude that the academic literature about degrowth would benefit from a more prominent discussion of the political implications of its ideas and proposals, and that in particular the debate about distributional policy implications of degrowth should be more prominent and concrete, with a stronger focus on distributional policies in a degrowing economy.

Description: The Yangtze River Delta (YRD) region frequently experiences ozone pollution events during the summer and autumn seasons. High-concentration events are typically related to synoptic weather patterns, which impact the transport and photochemical production of ozone at multiple scales, ranging from the local to regional scale. To better understand the regional ozone pollution problem, studies on ozone source attribution are needed, especially regarding the contributions of sources at different vertical heights based on tagging the region or time periods. Between September 3 and 8, 2020, an episode of ozone concentration anomaly high was observed in Hefei through ground-based stations and ozone Lidar. The mechanism behind this event was uncovered through synoptic weather pattern analysis and using the Weather Research and Forecasting Chemistry model (WRF-Chem). Because an approaching typhoon caused variable wind direction, the O3-rich air masses (ORMs) arising from the YRD region were transported to Hefei via the nocturnal residual layer and descended to the ground through horizontal advection and vertical mixing processes the next day. Based on geographic source tagging, the anthropogenic NOx emissions (ANEs) from local and regional sources were the main contributors to the heavy ozone pollution over Hefei on September 6. Furthermore, the intra-regional transported ozone from southern Jiangsu (SJS), southern Anhui (SAH), and Zhejiang (ZJ) in the YRD was the main driving factor of the surface and upper atmosphere ozone pollution. Based on time period tagging, The ozone generated due to ANEs from September 3 to 5 significantly contributed to this episode. It is important to pay attention to the impact of ANEs on September 5 on the surface peak ozone concentration the following day (i.e., September 6). Our findings provide significant insights into the regional ozone transport mechanism in the YRD and optimization of measures to prevent and control heavy ozone pollution on spatiotemporal scales.

Description: In this paper, the authors discuss the role of China in the emerging geopolitics of hydrogen. It begins with a review of China's external energy policy and its evolution over the past decades, highlighting China's transition to a net-energy importer as an important inflection point in that process. It then goes on to describe the main pillars of China's national hydrogen policy. Building on this the paper provides and overview of China's external hydrogen policy and how this aligns with both its broader energy foreign policy and its hydrogen policy objectives. The paper finds that China’s hydrogen strategy – both internal and external – are still at an emergent stage. National targets remain modest, and policy remains ambiguous regarding the preferred production pathway. China’s long-term vision clearly emphasizes the role of renewable hydrogen to help balance an energy system dominated by wind and solar energy. However, current policy provides ample space for the promotion of other forms of hydrogen production. Rather, than a strong, centralized policy approach, local and provincial governments along with SOEs have been driving investment and policy experimentation in the sector, which includes efforts to boost fossil-based hydrogen production.

Description: As a variant of Support Vector Machine (SVM), Large Margin Distribution Machine (LDM) has been validated to outperform SVM both theoretically and experimentally. Due to the inevitable noise in real applications, the credibility of different samples is not necessarily the same, which is neglected by most existing LDM models. To tackle the above problem, this paper first introduces fuzzy set theory into LDM, and proposes a Fuzzy Large Margin Distribution Machine (FLDM) with better robustness and performance. Considering the noise and uncertainty in datasets, sample points farther from the center of homogenous class are less reliable. Therefore, a fuzzy membership function based on the distance to the class center is utilized to characterize the confidence of each sample, i.e., the degree to which the sample belongs to a certain category. Furthermore, different strategies are developed to obtain class centers for linearly separable and linearly inseparable problems. Experiments conducted on both artificial and UCI datasets verified the superiority of FLDM from different perspectives.

Description: The problem of network disintegration, such as suppression of an epidemic spread and destabilization of terrorist networks, possesses extensive applications and has lately been the focus of growing interest. Many real-world complex systems are represented by spatial networks in which nodes and edges are spatially embedded. However, existing disintegration approaches for spatial network disintegration focus on singular aspects such as geospatial information or network topography, with insufficient modeling granularity. In this paper, we propose an effective and computationally efficient virtual node model that essentially integrates the geospatial information and topology of the network by modeling edges as virtual nodes with weights. Moreover, we employ Kernel Density Estimation, a well-known non-parametric technique for estimating the underlying probability density function of samples, to fit all nodes, comprising both network and virtual nodes, to identify the critical region of the spatial network, which is also the circular geographic region where disintegration occurs. Extensive numerical experiments on synthetic and real-world networks demonstrate that our method outperforms existing methods in terms of both effectiveness and efficiency, which provides a fresh perspective for modeling spatial networks.

Description: Bioenergy with carbon capture and storage (BECCS) can help stabilize the climate by extracting carbon dioxide from the atmosphere while producing renewable energy. However, biomass availability would limit the potential of BECCS, and biomass cropland expansion may threaten biodiversity, food security, and water supply. Replacing land-intensive foods can help unlock sustainable biomass production. Here, we estimated BECCS energy and negative emissions using biomass grown on freed-up land when replacing animal-source foods. Biomass production excludes agricultural expansion to protect biodiversity, ensures enough food supply globally to safeguard food security, and constrains irrigation to secure water for people and ecosystems. Negative emissions consider supply chain emissions and the forgone sequestration from natural revegetation. Results show that replacing 50% of animal products by 2050 could release enough land for BECCS to generate 26.4–39.5 EJelec/year, the scale of coal power today, while removing 5.9–9.3 GtCO2e/year from the atmosphere, almost what coal power emits today.

Description: We investigated the influence of the El Niño-Southern Oscillation (ENSO) on inter-annual precipitation variability in the far-eastern Pacific (FEP) and northern South America (NSA) using an approach based on phase synchronization (PS). First, we carried out a detailed analysis of observational data to define the inter-annual variability, eliminate the seasonal residual frequencies in hydro-climatic anomalies, and assess the statistical significance of PS. Additionally, we characterized the seasonality of regional patterns of sea surface temperature, surface pressure levels, low-level winds and precipitation anomalies associated with the ENSO states. We found that the positive (negative) precipitation anomalies experienced in the FEP and NSA differ from those previously reported in the literature. In particular, the Guianas (northeastern Amazon) and the Caribbean constitute two regions with negative (positive) rainfall anomalies during El Niño (La Niña), separated by a zone of non-significant anomalies along the Orinoco Low-level Jet corridor. Moreover, we showed that the ENSO signal is phase-locked with inter-annual rainfall and low-level wind variability in most of the study regions. Furthermore, we found consistency in the PS between the Central and Eastern Pacific El Niño indices and hydroclimatic anomalies over the Pacific. However, some areas exhibited PS, although they did not show significant precipitation anomalies, suggesting that the influence of ENSO on tropical climatology manifests not only in terms of the magnitude of anomalies but also in terms of the phases only. Our approach advances the understanding of climatic anomalies in tropical regions and provides new insights into the non-linear interactions between ENSO and hydroclimatic processes in tropical Americas.

Description: Lack of nitrogen limits food production in poor countries while excessive nitrogen use in industrial countries has led to transgression of the planetary boundary. However, the potential of spatial redistribution of nitrogen input for food security when returning to the safe boundary has not been quantified in a robust manner. Using an emulator of a global gridded crop model ensemble, we found that redistribution of current nitrogen input to major cereals among countries can double production in the most food insecure countries, while increasing global production of these crops by 12% with no notable regional loss or reducing the nitrogen input to the current production by one third. Redistribution of the input within the boundary increased production by 6–8% compared to the current relative distribution, increasing production in the food insecure countries by two thirds. Our findings provide georeferenced guidelines for redistributing nitrogen use to enhance food security while safeguarding the planet.

Description: Oil seed crops are the second most important field crops after cereals in the agricultural economy globally. The use and demand for oilseed crops such as groundnut, soybean and sunflower have grown significantly, but climate change is expected to alter the agroecological conditions required for oilseed crop production. This study aims to present an approach that utilizes decision-making tools to assess the potential climate change impacts on groundnut, soybean and sunflower yields and the greenhouse gas emissions from the management of the crops. The Decision Support Tool for Agrotechnology Transfer (DSSAT v4.7), a dynamic crop model and the Cool Farm Tool, a GHG calculator, was used to simulate yields and estimate GHG emissions from these crops, respectively. Four representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5), three nitrogen (0, 75, and 150 kg/ha) and phosphorous (0, 30 and 60 P kg/ha) fertilizer rates at three sites in Limpopo, South Africa (Ofcolaco, Syferkuil and Punda Maria) were used in field trials for calibrating the models. The highest yield was achieved by sunflower across all crops, years and sites. Soybean yield is projected to decrease across all sites and scenarios by 2030 and 2050, except at Ofcolaco, where yield increases of at least 15.6% is projected under the RCP 4.5 scenario. Positive climate change impacts are predicted for groundnut at Ofcolaco and Syferkuil by 2030 and 2050, while negative impacts with losses of up to 50% are projected under RCP 8.5 by 2050 at Punda Maria. Sunflower yield is projected to decrease across all sites and scenarios by 2030 and 2050. A comparison of the climate change impacts across sites shows that groundnut yield is projected to increase under climate change while notable yield losses are projected for sunflower and soybean. GHG emissions from the management of each crop showed that sunflower and groundnut production had the highest and lowest emissions across all sites respectively. With positive climate change impacts, a reduction of GHG emissions per ton per hectare was projected for groundnuts at Ofcolaco and Syferkuil and for sunflower in Ofcolaco in the future. However, the carbon footprint from groundnut is expected to increase by 40 to 107% in Punda Maria for the period up to 2030 and between 70-250% for 2050, with sunflower following a similar trend. We conclude that climate change will potentially reduce yield for oilseed crops while management will increase emissions. Therefore, in designing adaptation measures, there is a need to consider emission effects to gain a holistic understanding of how both climate change impacts on crops and mitigation efforts could be targeted.

Description: The planetary boundaries framework defines a safe operating space for humanity. To date, these boundaries have mostly been investigated separately, and it is unclear whether breaching one boundary can lead to the transgression of another. By employing a dynamic global vegetation model, we systematically simulate the strength and direction of the effects of different transgression levels of the climate change boundary (using climate output from ten CMIP6 models for CO2 levels ranging from 350 ppm to 1000 ppm). We focus on climate change-induced shifts of Earth’s major forest biomes, the control variable for the land-system change boundary, both by the end of this century and, to account for the long-term legacy effect, by the end of the millennium. Our simulations show that while staying within the 350 ppm climate change boundary co-stabilizes the land-system change boundary, breaching it (〉450 ppm) leads to its critical transgression with greater severity, the higher the ppm level rises and the more time passes. Specifically, this involves a poleward treeline shift, boreal forest dieback (nearly completely within its current area under extreme climate scenarios), competitive expansion of temperate forest into today’s boreal zone, and a slight tropical forest extension. These interacting changes also affect other planetary boundaries (freshwater change and biosphere integrity) and provide feedback to the climate change boundary itself. Our quantitative process-based study highlights the need for interactions to be studied for a systemic operationalization of the framework.

Description: Ecosystems are under multiple stressors and impacts can be measured with multiple variables. Humans have altered mass and energy flows of basically all ecosystems on Earth towards dangerous levels. However, integrating the data and synthesizing conclusions is becoming more and more complicated. Here we present an automated and easy to apply R package to assess terrestrial biosphere integrity which combines 2 complementary metrics: The BioCol metric quantifies the human colonization pressure exerted on the biosphere through alteration and extraction (appropriation) of net primary productivity, whereas the EcoRisk metric quantifies biogeochemical and vegetation structural changes as a proxy for the risk of ecosystem destabilization. Applied to simulations with the dynamic global vegetation model LPJmL5 for 1500–2016, we find that presently (period 2007–2016), large regions show modification and extraction of 〉25 % of the preindustrial potential net primary production, leading to drastic alterations in key ecosystem properties and suggesting a high risk for ecosystem destabilization. In consequence of these dynamics, EcoRisk shows particularly high values in regions with intense land use and deforestation, but also in regions prone to impacts of climate change such as the arctic and boreal zone. The metrics presented here enable global-scale, spatially explicit evaluation of historical and future states of the biosphere and are designed for use by the wider scientific community, not only limited to assessing biosphere integrity, but also to benchmark model performance. The package will be maintained on GitHub and through that we encourage application also to other models and data sets.

Description: Advances in the field of extreme event attribution allow to estimate how anthropogenic global warming affects the odds of individual climate disasters, such as river floods. Extreme event attribution typically uses precipitation as proxy for flooding. However, hydrological processes and antecedent conditions make the relation between precipitation and floods highly nonlinear. In addition, hydrology acknowledges that changes in floods can be strongly driven by changes in land-cover and by other human interventions in the hydrological system, such as irrigation and construction of dams. These drivers can either amplify, dampen or outweigh the effect of climate change on local flood occurrence. Neglecting these processes and drivers can lead to incorrect flood attribution. Including flooding explicitly, that is, using data and models of hydrology and hydrodynamics that can represent the relevant hydrological processes, will lead to more robust event attribution, and will account for the role of other drivers beyond climate change. Existing attempts are incomplete. We argue that the existing probabilistic framework for extreme event attribution can be extended to explicitly include floods for near-natural cases, where flood occurrence was unlikely to be influenced by land-cover change and human hydrological interventions. However, for the many cases where this assumption is not valid, a multi-driver framework for conditional event attribution needs to be established. Explicit flood attribution will have to grapple with uncertainties from lack of observations and compounding from the many processes involved. Further, it requires collaboration between climatologists and hydrologists, and promises to better address the needs of flood risk management.

Description: Natural hazards pose significant risks to people and assets in many regions of the world. Quantifying associated risks is crucial for many applications such as adaptation option appraisal and insurance pricing. However, traditional risk assessment approaches have focused on the impacts of single hazards, ignoring the effects of multi-hazard risks and potentially leading to underestimations or overestimations of risks. In this work, we present a framework for modelling multi-hazard risks globally in a consistent way, considering hazards, exposures, vulnerabilities, and assumptions on recovery. We illustrate the approach using river floods and tropical cyclones impacting people and physical assets on a global scale in a changing climate. To ensure physical consistency, we combine single hazard models that were driven by the same climate model realizations. Our results show that incorporating common physical drivers and recovery considerably alters the multi-hazard risk. We finally demonstrate how our framework can accommodate more than two hazards and integrate diverse assumptions about recovery processes based on a national case study. This framework is implemented in the open-source climate risk assessment platform CLIMADA and can be applied to various hazards and exposures, providing a more comprehensive approach to risk management than conventional methods.

Description: On the path to climate neutrality, global production locations and trade patterns of basic materials might change due to the heterogeneous availability of renewable electricity. Here we estimate the ‘renewables pull’, which is the energy-cost savings, for varying depths of relocation for three key tradable energy-intensive industrial commodities: steel, urea and ethylene. For an electricity-price difference of €40 MWh−1, we find respective relocation savings of 18%, 32% and 38%, which might, despite soft factors in the private sector, lead to green relocation. Conserving today’s production patterns by shipping hydrogen is substantially costlier, whereas trading intermediate products could save costs while keeping substantial value creation in renewable-scarce importing regions. In renewable-scarce regions, a societal debate on macroeconomic, industrial and geopolitical implications is needed, potentially resulting in selective policies of green-relocation protection.

Description: This analysis assesses the financial viability of legally investing in native Cerrado vegetation deforestation for crop production, considering climate change. The study uses data from twelve different crop models based on three different climate models to evaluate potential future crop yields in cleared land for growing soy and maize. The outcomes show that in many micro-regions, investments in clearing land for crop production would destroy economic value, that is, generate a negative net present value because of low/negative and volatile cashflows driven primarily by future yields as affected by climate. Our analysis was carried out based on present agricultural practices and technology. As climate changes, farmers may adapt their practices, which can lead to more resilient and productive crops, or grow different crops, which could provide better returns on investment in clearing land than the ones resulting from our analysis. Despite various uncertainties, farmers, policy makers and financial institutions should be aware of the climatic and financial risks associated with land clearing in Brazil, mainly in micro-regions in which all scenarios resulted in negative outcomes in the investment analysis. This study indicates that land expansion opportunities on degraded land should be prioritized over additional land clearing.

Description: The IPCC Assessment Reports offer the scientific foundation for international climate negotiations and constitute an unmatched resource for climate change researchers. However, the assessment cycles take multiple years. As a contribution to cross- and interdisciplinary understanding across diverse climate change research communities, we have streamlined an annual process to identify and synthesise essential research advances. We collected input from experts on different fields using an online questionnaire and prioritised a set of ten key research insights with high policy relevance. This year we focus on: (1) looming overshoot of the 1.5°C warming limit, (2) urgency of phasing-out fossil fuels, (3) challenges for scaling carbon dioxide removal, (4) uncertainties regarding the future of natural carbon sinks, (5) need for join governance of biodiversity loss and climate change, (6) advances in the science of compound events, (7) mountain glacier loss, (8) human immobility in the face of climate risks, (9) adaptation justice, and (10) just transitions in food systems. We first present a succinct account of these Insights, reflect on their policy implications, and offer an integrated set of policy relevant messages. This science synthesis and science communication effort is also the basis for a report targeted to policymakers as a contribution to elevate climate science every year, in time for the UNFCCC COP.

Description: This paper looks into the crucial macroeconomic feedback mechanisms emerging from the interplay among the goods market, the labor market, the financial sector, and monetary policy, particularly in the context of transitioning towards a climate-neutral economy. The investment decisions of firms, pivotal in this interaction, can trigger feedback loops with potentially destabilizing effects, underscoring the critical role of investment within the complex interplay of market and sector dynamics in the macroeconomy. Governmental intervention is highlighted as a key factor in steering the green transition while preserving economic stability. A carbon tax on fossil fuel consumption is proposed as a primary tool for facilitating this green transition. Our investigation employs a disequilibrium model of monetary growth, a la Keynes-Metzler-Goodwin (KMG), incorporating a portfolio perspective across three asset markets - money, bonds, and stocks. This framework allows for an in-depth analysis of how a carbon tax influences real production, inflation, and inequality during the transition. Our findings indicate that imposing a carbon tax on production does not markedly disrupt economic stability, as long as the carbon pricing and its growth rate remain within low bounds.

Description: Climate policy needs to set incentives for investors who face imperfect, distorted markets and large uncertainties about the costs and benefits of abatement. These investors decide on uncertain investments according to their expected return and risk (carbon beta). We study carbon pricing and financial incentives in a consumption-based asset pricing model distorted by technology spillovers and time-inconsistency. We find that both distortions reduce the equilibrium asset return and delay investment in abatement. However, their effect on the carbon beta and the risk premium for abatement can be decreasing (when innovation spillovers are not anticipated) or increasing (when climate policy is not credible). We show that the distortions can be overcome by modified carbon pricing by a regulator, or by financial incentives, implemented in our model by a long-term investment fund. The fund pays a subsidy to reduce technology costs or offers financial contracts to boost investment returns to complement the carbon price. The investment fund can thus pave the way for carbon pricing in later periods by preventing a capital misallocation that would be too expensive to correct, thus improving the feasibility of ambitious carbon pricing.

Description: We study the impact of recent global warming on extreme climatic events in Central Asia (CA) for 1901-2019 by comparing the composite representation of the observational climate with a hypothetical counterfactual one that does not include the long-term global warming trend. The counterfactual climate data are produced based on a simple detrending approach, using the global mean temperature (GMT) as the independent variable and removing the long-term trends from the climate variables of the observational data. This trend elimination is independent of causality, and the day-to-day variability in the counterfactual climate remains preserved. The analysis done in the paper shows that the increase in frequency and magnitude of extreme temperature and precipitation events can be attributed to global warming. Specifically, the probability of experiencing a +7 K temperature anomaly event in CA increases by up to a factor of seven in some areas due to global warming. The analysis reveals a significant increase in heatwave occurrences in Central Asia, with the observational climate dataset GSWP3-W5E5 (later called also factual) showing more frequent and prolonged extreme heat events than hypothetical scenarios without global warming. This trend, evident in the disparity between factual and counterfactual data, underscores the critical impact of recent climatic changes on weather patterns, highlighting the urgent need for robust adaptation and mitigation strategies. Additionally, using the self-calibrated Palmer drought severity index (scPDSI), the sensitivity of dry and wet events to the coupled precipitation and temperature changes is analyzed. The areas under dry and wet conditions are enhanced under the observational climate compared to a counterfactual scenario, especially over the largest deserts in CA. The expansion of the dry regions aligns well with the pattern of desert development observed in CA in recent decades.

Description: This study investigates the attribution of climate change to trends in river discharge during six decades from 1955 until 2014 in 12 selected river catchments across six Central Asian countries located upstream of the main rivers. For this purpose, the semi-distributed eco-hydrological model SWIM (Soil and Water Integrated Model) was firstly calibrated and validated for all study catchments. Attributing climate change to streamflow simulation trends was forced by factual (reanalysis) and counterfactual climate data (assuming the absence of anthropogenic influence) proposed in the framework of the ISIMIP (Inter-Sectoral Impact Model Intercomparison Project) or ESM without anthropogenic forcing that were firstly tested and then compared. The trend analysis was performed for three variables: mean annual discharge and high flow (Q5) and low flow (Q95) indices. The results show that trends in the annual and seasonal discharge could be attributed to climate change for some of the studied catchments. In the three northern catchments (Derkul, Shagan, and Tobol), there are positive trends, and in two catchments (Sarysu and Kafirnigan), there are negative streamflow trends under the factual climate, which could be attributed to climate change. Also, our analysis shows that the average level of discharge in Murghab has increased during the historical study period due to climate change, despite the overall decreasing trend during this period. In addition, the study reveals a clear signal of shifting spring streamflow peaks in all catchments across the study area.

Description: This paper applies a mental model approach to study the role of tenure security in farmers’ decisionmaking on agricultural investment in Uganda. We investigate the role that both perceived tenure security and formal land rights, measured by the possession of land certificates, play. Our focus is on investment in improved seeds, a widely applied strategy in agricultural development and climate change adaptation. The study design leverages the roll-out of a large land demarcation and registration project, which creates exogenous variation in farmers’ tenure security. Results show that, in contrast to expectations derived from economic theory, tenure security plays only a minor role in farmers’ decision-making process to invest in improved seeds. Out of 15 potential factors determining a farmer’s investment decision, both perceived tenure security and possession of a land certificate are among the least chosen factors, regardless of whether or not households participated in the land registration project. A heterogeneity analysis reveals that female-headed households value formalized land rights more than male-headed households.

Description: In this paper we ask: why do people in rural agrarian communities facing increasing migration pressures from changing climatic conditions, stay? We aim to understand why people stay, who stays, what are the impacts of migration on those who stay, and what are their needs for adaptation? We study a population of people who do not migrate from Himalayan communities of Uttarakhand, India, despite their livelihoods being already severely disrupted by climate change climate change and high outmigration has led to abandoned so-called ‘ghost villages’. Semi-structured interviews (n = 72) were held with affected communities, experts, and policymakers. Results show that motivations for immobility are shaped by place attachment; place-based resource advantages; social milieu; dependence on subsistence agriculture and gender roles. We find that immobility experiences are differentiated by gender, age and in situ resources. Those who stay are negatively impacted by migration via loss of labour in agriculture, changes in population size and composition, loss of community, in addition to the negative impacts of climate change. Our results are likely relevant on a global scale, to other subsistence smallholder communities who stay despite increasing climate risks. These populations will need gender-sensitive support to adapt in place.

Description: To address climatic risks to human security, various climate security risk assessment (CSRA) tools have been developed. We have systematically reviewed 28 such tools against state-of-the-art research to (i) define best practices in CSRAs, (ii) identify related gaps in these tools and derive recommendations on how to address them, and (iii) outline a policy-relevant research agenda. We suggest the following measures to improve CSRA tools: Global South actors need to be more strongly involved in priority setting, conceptualization, risk analysis, and intervention design. CSRA tools should offer geographically disaggregated analyses, transparently explain choices regarding tools’ temporal and geographical foci, and assess their implications for the evidence. In this regard, any type of sampling bias should be avoided. Mixed methods can offer clear advantages to study the context-specific climate security dynamics across different time scales. The main gaps in the tools’ conceptualizations evolve around comprehensive consideration of risk determinants (climatic hazards, exposure, and vulnerability) and complex climate–security linkages, communication of uncertainty, and implementation of validation routines. These factors need to be better accounted for. To advance CSRAs, future research should, for example, develop methodologies to systematically integrate quantitative and qualitative approaches, improve the performance of risk predictions, and develop conflict projections.

Description: We analyze if exposure to weather risk affects the tenure security of smallholder farmers in rural Tanzania. Drawing on a household panel survey with three waves and high-resolution weather data, our identification strategy exploits exogenous variation in precipitation across time and space. Results from household fixed effects estimations show that exposure to weather risk significantly lowers farmers’ perceived tenure security, while it increases land conflicts. Moreover, weather risk influences the likelihood that farmers acquire land certificates. These findings suggest that both land formalization and land dispute resolution mechanisms are needed to cushion the impacts of weather risk.

Description: Forestation efforts are accelerating across the globe in the fight against global climate change, in order to restore biodiversity, and to improve local livelihoods. Yet, so far the non-local effects of forestation on rainfall have largely remained a blind spot. Here we build upon emerging work to propose that targeted rainfall enhancement may also be considered in the prioritization of forestation. We show that the tools to achieve this are rapidly becoming available, but we also identify drawbacks and discuss which further developments are still needed to realize robust assessments of the rainfall effects of forestation in the face of climate change. Forestation programs may then mitigate not only global climate change itself, but also its adverse effects in the form of drying.

Description: The planetary boundaries framework defines a safe operating space for humanity. To date, these boundaries have mostly been investigated separately, and it is unclear whether breaching one boundary can lead to the transgression of another. By employing a dynamic global vegetation model, we systematically simulate the strength and direction of the effects of different transgression levels of the climate change boundary (using climate output from ten phase 6 of the Coupled Model Intercomparison Project models for CO2 levels ranging from 350 ppm to 1000 ppm). We focus on climate change-induced shifts of Earth's major forest biomes, the control variable for the land-system change boundary, both by the end of this century and, to account for the long-term legacy effect, by the end of the millennium. Our simulations show that while staying within the 350 ppm climate change boundary co-stabilizes the land-system change boundary, breaching it (〉450 ppm) leads to critical transgression of the latter, with greater severity the higher the ppm level rises and the more time passes. Specifically, this involves a poleward treeline shift, boreal forest dieback (nearly completely within its current area under extreme climate scenarios), competitive expansion of temperate forest into today's boreal zone, and a slight tropical forest extension. These interacting changes also affect other planetary boundaries (freshwater change and biosphere integrity) and provide feedback to the climate change boundary itself. Our quantitative process-based study highlights the need for interactions to be studied for a systemic operationalization of the planetary boundaries framework.

Description: Today, more than 70 carbon pricing schemes have been implemented around the globe, but their contributions to emissions reductions remains a subject of heated debate in science and policy. Here we assess the effectiveness of carbon pricing in reducing emissions using a rigorous, machine-learning assisted systematic review and meta-analysis. Based on 483 effect sizes extracted from 80 causal ex-post evaluations across 21 carbon pricing schemes, we find that introducing a carbon price has yielded immediate and substantial emission reductions for at least 17 of these policies, despite the low level of prices in most instances. Statistically significant emissions reductions range between –5% to –21% across the schemes (–4% to –15% after correcting for publication bias). Our study highlights critical evidence gaps with regard to dozens of unevaluated carbon pricing schemes and the price elasticity of emissions reductions. More rigorous synthesis of carbon pricing and other climate policies is required across a range of outcomes to advance our understanding of “what works” and accelerate learning on climate solutions in science and policy.

Description: There has long been a debate about climate-damaging subsidies in the German transport sector, and the financial restrictions resulting from the Federal Constitutional Court’s budget judgement at the end of 2023 have intensified the debate. This dossier is the first to convert the level of subsidies in the transport sector into negative CO2 prices to present a scientific categorisation of their significance for climate policy. The concept of implicit negative CO2 prices shows the extent to which subsidies implicitly reward citizens for emitting a tonne of CO2, rather than paying for the emissions.

Description: Interest rates are central determinants of saving and investment decisions. Costly financial intermediation distorts these price signals by creating a spread between deposit and loan rates. This study investigates how bank spreads affect climate policy in its ambition to redirect capital. We identify various channels through which interest spreads affect carbon emissions in a dynamic general equilibrium model. Interest rate spreads increase abatement costs due to the higher relative price for capital-intensive carbon-free energy but they also tend to reduce emissions due to lower overall economic growth. For the global average interest rate spread of 5.1pp, global warming increases by 0.2°C compared to the frictionless economy. For a given temperature target to be achieved, interest rate spreads necessitate substantially higher carbon taxes. When spreads arise from imperfect competition in the intermediation sector, the associated welfare costs can be reduced by clean energy subsidies or even eliminated by economy-wide investment subsidies.

Description: We present transient simulations of the last glacial inception using the Earth system model CLIMBER-X with dynamic vegetation, interactive ice sheets, and visco-elastic solid Earth responses. The simulations are initialized at the middle of the Eemian interglacial (125 kiloyears before present, ka) and run until 100 ka, driven by prescribed changes in Earth's orbital parameters and greenhouse gas concentrations from ice core data. CLIMBER-X simulates a rapid increase in Northern Hemisphere ice sheet area through MIS5d, with ice sheets expanding over northern North America and Scandinavia, in broad agreement with proxy reconstructions. While most of the increase in ice sheet area occurs over a relatively short period between 119 and 117 ka, the larger part of the increase in ice volume occurs afterwards with an almost constant ice sheet extent. We show that the vegetation feedback plays a fundamental role in controlling the ice sheet expansion during the last glacial inception. In particular, with prescribed present-day vegetation the model simulates a global sea level drop of only ∼ 20 m, compared with the ∼ 35 m decrease in sea level with dynamic vegetation response. The ice sheet and carbon cycle feedbacks play only a minor role during the ice sheet expansion phase prior to ∼ 115 ka but are important in limiting the deglaciation during the following phase characterized by increasing summer insolation. The model results are sensitive to climate model biases and to the parameterization of snow albedo, while they show only a weak dependence on changes in the ice sheet model resolution and the acceleration factor used to speed up the climate component. Overall, our simulations confirm and refine previous results showing that climate–vegetation–cryosphere feedbacks play a fundamental role in the transition from interglacial to glacial states characterizing Quaternary glacial cycles.

Description: Human actions compromise the many life-supporting functions provided by the freshwater cycle. Yet, scientific understanding of anthropogenic freshwater change and its long-term evolution is limited. Here, using a multi-model ensemble of global hydrological models, we estimate how, over a 145-year industrial period (1861–2005), streamflow and soil moisture have deviated from pre-industrial baseline conditions (defined by 5th–95th percentiles, at 0.5° grid level and monthly timestep over 1661–1860). Comparing the two periods, we find an increased frequency of local deviations on ~45% of land area, mainly in regions under heavy direct or indirect human pressures. To estimate humanity’s aggregate impact on these two important elements of the freshwater cycle, we present the evolution of deviation occurrence at regional to global scales. Annually, local streamflow and soil moisture deviations now occur on 18.2% and 15.8% of global land area, respectively, which is 8.0 and 4.7 percentage points beyond the ~3 percentage point wide pre-industrial variability envelope. Our results signify a substantial shift from pre-industrial streamflow and soil moisture reference conditions to persistently increasing change. This indicates a transgression of the new planetary boundary for freshwater change, which is defined and quantified using our approach, calling for urgent actions to reduce human disturbance of the freshwater cycle.

Description: While it is widely assumed that poor countries will suffer more from climate change, and that climate change will exacerbate inequalities within countries, systematic and large-scale evidence on this issue has been limited. In this systematic literature review, we examine and synthesize the evidence from the literature. Drawing from 127 individual papers, we find robust evidence that climate change impacts indeed increase economic inequality and disproportionately affect the poor, both globally and within countries on all continents. This result is valid across a wide range of physical impacts, types of economic inequality, economic sectors, and assessment methods. Furthermore, we highlight the channels through which climate change increases economic inequality. While the diversity of different approaches and metrics in the existing literature base precludes extracting a universal quantitative relation between climate change and economic inequality for use in future modelling, our systematic analysis provides an important stepping stone in that direction.

Description: Some forty years ago, the UN Convention on the Law of the Sea 1982 (UNCLOS) created an unusual regime for states to collectively manage common natural resources on the international seabed beyond national jurisdiction (known as the Area) through the International Seabed Authority (ISA). In the intervening years, scientists have increasingly been warning about the serious environmental risks of mining seabed minerals. At this pivotal point in time, when states are negotiating whether or not to allow seabed mining, this essay explores the risk of undermining by mining, that is, contravening international marine environmental law and the obligations and responsibilities of states thereunder by allowing commercial mining activities to commence. We argue that allowing seabed mining in the Area at this juncture, when so much about the deep ocean remains unknown, would risk frustrating a host of measures, achievements, and progress to enhance marine environmental protection, particularly in areas beyond national jurisdiction. We begin with an overview of the ISA and its work to date, before discussing potential interactions between seabed mining and marine environmental law and policies, with a particular focus on the new ocean biodiversity agreement. We conclude by urging states to take cognizance of their overarching duty to protect and preserve the marine environment and ensure that all decisions taken with respect to seabed mining are consistent with their obligations and responsibilities under international law.

Description: Real-world laboratories have become a recognised research format for addressing sustainability challenges. In these transdisciplinary settings, actors from civil society, local government, and academia work together using a transdisciplinary research approach to jointly experiment and learn about sustainability transformations. While these labs are considered to have potential, their impact has not yet been fully measured. Therefore, in our paper we explore the case of the Zukunftsstadt Lüneburg 2030+ process to uncover the impacts that this long-term effort has generated over the past eight years. By examining the process and its design features from three analytical perspectives, we identify emergent impacts in three dimensions: education, governance, and the lab as an actor for sustainability. Based on our case study, we suggest that real-world labs contribute to sustainability on a local level, beyond the intentional experiments, through impacts that emerge over the course of the joint operation of the lab.

Description: Numerous scientific reports have evidenced the transformation of the earth system due to human activities. These changes – captured under the term ‘Anthropocene’ – require a new perspective on global law and policy. The concept of ‘earth system law’ situates law in an earth system context and offers a new perspective to interrogate the role of law in governing planetary challenges such as climate change. The discourse on earth system law has not yet fully recognised courts as actors that could shape climate governance, while climate litigation discourse has insufficiently considered aspects of earth system law. We posit that courts play an increasingly influential climate governance role and that they need to be recognised as Anthropocene institutions within the earth system law paradigm. Drawing on a set of prominent climate cases, we discuss five inter-related domains that are relevant for earth system law and where the potential influence of courts can be discerned: establishing accountability, redefining power relations, remedying vulnerabilities and injustices, increasing the reach and impact of international climate law and applying climate science to adjudicate legal disputes. We suggest that their innovative work in these domains could provide a basis for positioning courts as planetary climate governance actors.

Description: Germany, the European Union member state with the largest fiscal space and its leading manufacturer of industrial goods, is pursuing an ambitious hydrogen strategy aiming at establishing itself as a major technology provider and importer of green hydrogen. The success of its hydrogen strategy represents not only a key element in realizing the European vision of climate neutrality but also a central driver of an emerging global hydrogen economy. This article provides a detailed review of German policy, highlighting its prominent international dimension and its implications for the development of a global renewable hydrogen economy. It provides an overview of the strategy's central goals and how these have evolved since the launch of the strategy in 2020. Next, it moves on to provide an overview of the strategy's main areas of intervention and highlights corresponding policy instruments. For this, we draw on a comprehensive assessment of hydrogen policy instruments, which have been systematically analyzed and coded. This was complemented by a detailed analysis of policy documents and information gathered in six interviews with government officials and staff of key implementing agencies. The article places particular emphasis on the strategy's international dimension. While less significant in financial terms than domestic hydrogen-related spending, it represents a defining feature of the German hydrogen strategy, setting it apart from strategies in other major economies. The article closes with a reflection on the key features of the strategy compared to other important countries, identifies gaps of the strategy and discusses important avenues for future research.

Description: In two recent South African cases, Indigenous communities successfully challenged proposed fossil fuel exploration activities by the Shell petroleum company off South Africa's pristine West Coast. In contrast to earlier climate litigation cases in South Africa, the litigants relied specifically on their Indigenous rights and knowledge. In this case note, we highlight the ways in which the two courts engaged with the communities' cultural beliefs and practices as well as their knowledge related to sustainability and how this relates to protecting their livelihoods, cultural practices and identities that are threatened by the proposed activities. We highlight the important role played by Indigenous communities in the climate movement and argue that, in the future, Indigenous and related considerations could provide a strong basis for climate litigation in South Africa and potentially contribute to efforts to protect Indigenous communities against the activities of carbon majors.

Description: This article presents an enhanced emission module for the PALM model system, which collects discrete emission sources from different emission sectors and assigns them dynamically to the prognostic equations for specific pollutant species as volumetric source terms. Bidirectional lookup between each source location and cell index are maintained through using a hash key approach, while allowing all emission source modules to be conceived, developed and operated in a homogeneous and mutually independent manner. An additional generic emission mode has also been implemented to allow the use of external emission data in simulation runs. Results from benchmark runs indicate a high level of performance and scalability. Subsequently, a module for modelling parametrized emissions from domestic heating is implemented under this framework, using the approach of building energy usage and temperature deficit as a generalized form of heating degree days. An model run has been executed under idealized conditions by considering solely dispersion of PM10 from domestic heating sources. The results demonstrate a strong overall dependence on the strength and clustering of individual sources, diurnal variation in domestic heat usage, as well as the temperature deficit between the ambient and the user-defined target temperature. Vertical transport contributes additionally to a rapid attenuation of daytime PM10. Although urban topology plays a minor role on the pollutant concentrations at ground level, it has a relevant contribution to the vertical pollutant distribution.

Description: Global projections of macroeconomic climate-change damages typically consider impacts from average annual and national temperatures over long time horizons. Here we use recent empirical findings from more than 1,600 regions worldwide over the past 40 years to project sub-national damages from temperature and precipitation, including daily variability and extremes. Using an empirical approach that provides a robust lower bound on the persistence of impacts on economic growth, we find that the world economy is committed to an income reduction of 19% within the next 26 years independent of future emission choices (relative to a baseline without climate impacts, likely range of 11–29% accounting for physical climate and empirical uncertainty). These damages already outweigh the mitigation costs required to limit global warming to 2 °C by sixfold over this near-term time frame and thereafter diverge strongly dependent on emission choices. Committed damages arise predominantly through changes in average temperature, but accounting for further climatic components raises estimates by approximately 50% and leads to stronger regional heterogeneity. Committed losses are projected for all regions except those at very high latitudes, at which reductions in temperature variability bring benefits. The largest losses are committed at lower latitudes in regions with lower cumulative historical emissions and lower present-day income.

Description: Are there group decision methods which (i) give everyone, including minorities, an equal share of effective decision power even when voters act strategically, (ii) promote consensus and equality, rather than polarization and inequality, and (iii) do not favour the status quo or rely too much on chance? We describe two non-deterministic group decision methods that meet these criteria, one based on automatic bargaining over lotteries, the other on conditional commitments to approve compromise options. Using theoretical analysis, agent-based simulations and a behavioral experiment, we show that these methods prevent majorities from consistently suppressing minorities, which can happen in deterministic methods, and keeps proponents of the status quo from blocking decisions, as in other consensus-based approaches. Our simulations show that these methods achieve aggregate welfare comparable to common voting methods, while employing chance judiciously, and that the welfare costs of fairness and consensus are small compared to the inequality costs of majoritarianism. In an incentivized experiment with naive participants, we find that a sizable fraction of participants prefers to use a non-deterministic voting method over Plurality Voting to allocate monetary resources. However, this depends critically on their position within the group. Those in the majority show a strong preference for majoritarian voting methods.

Description: The global steel sector is responsible for 7% of global greenhouse gas emissions, highlighting the need for significant changes in production practices and the adoption of low-carbon breakthrough technologies to achieve net-zero emissions. This study was conducted to explore positive tipping points at the company level, taking into account socio-political, economic and industry pressures that initiate the tipping process. The study operationalizes tipping points using the Triple Embededdness Framework, which incorporates indicators from the socio-political and economic environment, as well as the industry regime of companies. An analysis is performed of secondary data from four steel companies: BlueScope (Australia), POSCO (South Korea), voestalpine (Austria), and U.S. Steel (USA). The findings indicate that voestalpine is on the verge of reaching a positive tipping point, and POSCO is also on a promising track. In contrast, both BlueScope and U.S. Steel are lagging behind. In the tipping process, national policies play a critical role in expediting the transition to low-carbon steel production for frontrunners, while global climate policy has a greater leverage by influencing producers who operate in a less stringent national policy context. Additionally, the customer demand for low-carbon steel serves as a driving force for innovation and can incentivize steelmakers to produce low-carbon products.

Description: Increasing interconnectedness, along with the effects of climate change and other global risk drivers, has led to mounting systemic risks in the complex systems that characterize our world. Systemic risks, with their cascading impacts and long-term sustainability concerns, necessitate transformative approaches to manage their effects across system scales and dimensions. To date, however, an “operationalization gap” impedes translating between propositions for transformative change and policy options for addressing systemic risk. Here, we propose combining systemic risk analyses with local approaches, prominently including knowledge co-production, to achieve a more comprehensive understanding of complex systems. This combined approach can support stakeholders in designing transformative risk management and adaptation interventions that balance individual and higher-order interactions, incorporate diverse viewpoints, and thus manage systemic risks and leverage transformation potential more effectively. Furthermore, we suggest that a risk-layering approach can help differentiate, prioritize, and orchestrate these options for incremental and transformative changes.

Description: Process-based forest models combine biological, physical, and chemical process understanding to simulate forest dynamics as an emergent property of the system. As such, they are valuable tools to investigate the effects of climate change on forest ecosystems. Specifically, they allow testing of hypotheses regarding long-term ecosystem dynamics and provide means to assess the impacts of climate scenarios on future forest development. As a consequence, numerous local-scale simulation studies have been conducted over the past decades to assess the impacts of climate change on forests. These studies apply the best available models tailored to local conditions, parameterized and evaluated by local experts. However, this treasure trove of knowledge on climate change responses remains underexplored to date, as a consistent and harmonized dataset of local model simulations is missing. Here, our objectives were (i) to compile existing local simulations on forest development under climate change in Europe in a common database, (ii) to harmonize them to a common suite of output variables, and (iii) to provide a standardized vector of auxiliary environmental variables for each simulated location to aid subsequent investigations. Our dataset of European stand- and landscape-level forest simulations contains over 1.1 million simulation runs representing 135 million simulation years for more than 13,000 unique locations spread across Europe. The data were harmonized to consistently describe forest development in terms of stand structure (dominant height), composition (dominant species, admixed species), and functioning (leaf area index). Auxiliary variables provided include consistent daily climate information (temperature, precipitation, radiation, vapor pressure deficit) as well as information on local site conditions (soil depth, soil physical properties, soil water holding capacity, plant-available nitrogen). The present dataset facilitates analyses across models and locations, with the aim to better harness the valuable information contained in local simulations for large-scale policy support, and for fostering a deeper understanding of the effects of climate change on forest ecosystems in Europe.

Description: The Texas power grid on the Gulf Coast of the United States is frequently hit by tropical cyclones (TCs) causing widespread power outages, a risk that is expected to substantially increase under global warming. Here we introduce a new approach that combines a probabilistic line failure model with a network model of the Texas grid to simulate the spatio-temporal co-evolution of wind-induced failures of high-voltage transmission lines and the resulting cascading power outages from seven major historical TCs. The approach allows reproducing observed supply failures. In addition, compared to existing static approaches, it provides a notable advantage in identifying critical lines whose failure can trigger large supply shortages. We show that hardening only 1% of total lines can reduce the likelihood of the most destructive type of outage by a factor of between 5 and 20. The proposed modelling approach could represent a so far missing tool for identifying effective options to strengthen power grids against future TC strikes, even under limited knowledge.

Description: The Greenland Ice Sheet and Atlantic Meridional Overturning Circulation are considered tipping elements in the climate system, where global warming exceeding critical threshold levels in forcing can lead to large-scale and nonlinear reductions in ice volume and overturning strength, respectively. The positive-negative feedback loop governing their interaction (with a destabilizing effect on the AMOC due to ice loss and subsequent freshwater flux into the North Atlantic as well as a stabilizing effect of a net-cooling around Greenland with an AMOC weakening) may determine the long-term stability of both tipping elements. Here we explore the potential dynamic regimes arising from this positive-negative tipping feedback loop in a process-based conceptual model. Under idealized forcing scenarios we identify conditions under which different kinds of tipping cascades can occur: Herein, we distinguish between overshoot tipping cascades (leading to tipping of both GIS and AMOC) and rate-induced tipping cascades (where the AMOC despite not having crossed its own intrinsic tipping point tips nonetheless due to the fast rate of ice loss from Greenland). These different cascades occur within corridors of distinct tipping pathways that are affected by the GIS melting patterns and thus eventually by the imposed forcing and its time scales. Our results suggest that it is not only necessary to avoid breaching the respective critical levels of the environmental drivers for the Greenland Ice Sheet and Atlantic Meridional Overturning Circulation, but also to respect safe rates of environmental change to mitigate potential domino effects.

Description: The potential for renewable energy to encourage sustainable development raises high hopes for the future among countries in the Global South. However, there has been less research on how energy transitions are perceived outside of the Global North and democratic contexts. This paper explores attitudes towards the energy transition in Jordan, where expert interviews reveal that a strong renewable energy industry has emerged from top-down government efforts to reduce energy dependency and costs. We perform an in-person household survey with 320 respondents in areas with different transition risks and benefits, and then test a series of hypotheses using regression analysis. In the four communities surveyed, income stress and climate concern influence attitudes, as well as perceptions of community benefits. National-level concerns also matter, including energy dependency and energy costs for all Jordanians. Our results highlight the importance of context: findings from the North are not universal and understanding transitions in the Global South requires studying them in their own right. Policy insights Jordanian policymakers should reverse their policy of blocking renewables to avoid public backlash. Jordanian policymakers and funders should promote projects in communities with high economic dependence on the fossil fuel industry to ensure local support in areas facing transition risks. Policymakers should highlight collective, not just individual benefits of transitions, as perceptions of community and country benefits increase support. Policymakers in highly energy-dependent countries like Jordan should frame renewables as an answer to local and national challenges such as high energy prices. Actors wishing to promote clean energy support in different contexts should investigate local dynamics to build communication strategies that frame transitions appropriately. Jordanian policymakers should reverse their policy of blocking renewables to avoid public backlash. Jordanian policymakers and funders should promote projects in communities with high economic dependence on the fossil fuel industry to ensure local support in areas facing transition risks. Policymakers should highlight collective, not just individual benefits of transitions, as perceptions of community and country benefits increase support. Policymakers in highly energy-dependent countries like Jordan should frame renewables as an answer to local and national challenges such as high energy prices. Actors wishing to promote clean energy support in different contexts should investigate local dynamics to build communication strategies that frame transitions appropriately.

Description: Urban heat island (UHI) not only reflects the environmental thermal comfort and energy consumption, but also affects the urban meso‑scale climate. There are many researches related with UHI mainly focusing on urban and rural area, while neglecting dynamic rural–urban transition especially in a rapid urbanization in China. Beijing and Zhengzhou are studied by using city clustering algorithm (CCA) and boundary generation algorithm (BGA) to delineate the urban, peri‑urban and rural boundaries from 2000 to 2023 within three stages. Fourier transform model was used to identify the UHI patterns. Results show: 1) Two cities have undergone obvious expansions in 20 years, with a consistent mean LST decrease from urban to peri‑urban and rural areas in three stages. 2) The distribution of UHII was more consistent in Beijing, while it varied more in Zhengzhou across seasons. 3) The UHI patterns notably differ, with Zhengzhou experiencing variable patterns and Beijing consistently showing oblate patterns. 4) The profiles of UHII and NDVI in two cities varied seasonally and reflected urban expansions in terms of longitude and latitude. Understanding the long-term changes and patterns of urban heat islands in different cities will provide information for formulating adaptive policies for urban sustainability.