ALBERT

Beschreibung: The twenty-eighth Conference of the Parties (COP28) to the United Nations Framework Convention on Climate Change (UNFCCC) in Dubai among many other items concluded the first Global Stocktake (GST) under the Paris Agreement. This article discusses the conference's outcomes in the areas of mitigation, loss and damage, adaptation, climate finance, and cooperation under Article 6 of the Paris Agreement. The conference arguably made history by for the first time ever recognising the need to "transition away" from fossil fuels, adopting specific targets for the scale-up of renewable energy and energy efficiency, and by operationalising a fund to support developing countries in dealing with loss and damage caused by climate change. However, the legal language in the call for an energy transition is relatively non-committal and the conference failed to underpin the new global objectives with adequate resources. Actual implementation of the Dubai outcomes will therefore to a large extent depend on whether COP29 in Baku, Azerbaijan - already billed as "finance COP" - will be able to cut the Gordian knot of finance.

Beschreibung: North Rhine-Westphalia (NRW) is the industrial center of Germany and one of the most important industrial locations in Europe. It is a key location for the energy-intensive basic materials industry like the production of steel and non-ferrous metals, (petro)chemicals, cement and lime, bricks, glass and ceramics, and paper. Around 20 % of NRW's total greenhouse emissions derive from industrial processes. By 2045, industry must achieve climate-neutrality, which requires a massive transformation effort. Technologically, this needs large-scale utilization of green hydrogen, carbon management, consequent circular economy, and climate-neutral production of process heat. Furthermore, various adjustments to the policy framework are essential.

Beschreibung: Over 175 million Nigerians rely on the use of traditional biomass for cooking, and it is estimated that more than 128,000 people died in Nigeria in 2019 from household air pollution related to these fuels. There is currently a gap in the study of possible pathways to meet Nigeria's goals in clean cooking and in understanding the health and climate impacts that different pathways can bring about. We explore clean cooking access scenarios for Nigeria until 2060 under a business-as-usual scenario, a moderate climate mitigation scenario, and an ambitious transformative scenario. We carry out a disaggregation at the state level for the period up to 2030 to better guide shorter-term policy development. Our analysis shows that under an ambitious scenario where 85 million households achieve access to clean cooking by 2060, annual premature deaths due to exposure to household air pollution would decrease by 7 % compared to 2018 levels. A baseline scenario, on the other hand, sees a dramatic 77 % increase, resulting in 209,000 people dying prematurely, of which 94,000 children under 5. Furthermore, we find that woodfuel removals from forestland would lead to a tripling of carbon dioxide emissions from land use change, reaching 602 Mt CO2 by 2060. Our findings stress the vital importance of a clean cooking transition in Nigeria and underline the urgent need for immediate acceleration in national efforts regarding access to clean cooking for all.

Beschreibung: The goal of this dissertation is to facilitate the assessment of impacts from sustainable measures and projects with an emphasis on impact reporting for Green, Social or Sustainability Bonds in the Sustainable Finance market. It does so by providing analysts with the means to develop, depict, formulate, and assess a causal hypothesis between an intervention and its subsequent effects in an impact-chain, represented by desired environmental (E), social (S) or governance (G) changes. This is achieved by developing a methodology for so-called ESG Logic Models or ESG-LM, that combine heuristic Theories-of-Change with propositional logic and Bayesian Reasoning. Three research questions are investigated and responded to. Research Question 1 asks how such Theories-of-Change can be developed for any type of ESG-related issue and how the different process steps in a causal chain can be classified, hierarchised, and prioritised regarding their efficacy towards overarching sustainability goals and their plausibility. Research Question 2 studies (a) the means by which the analyst or any other interested third party might be warranted in believing the causal claims from an ESG-LM, and (b) how an ESG-LM can be improved if this credence is low. Research Question 3 then looks at the reporting of impacts themselves regarding indicator selection, indicator assessment and indicator quantification as well as the provision of information on the contributions and attributions by different actors. The dissertation draws on a variety of theories and adapts existing methods to achieve that. It operationalises concepts from empirical Sustainable Finance research and already existing impact assessment methodologies. It adapts scholarly and practitioner approaches for theory-based evaluation and applies a qualitative social science perspective towards theory-building and evaluation, while some of the assessment tools in the dissertation are grounded in Logic, Set Theory and Bayesian Epistemology. Examples for such tools include rules for the Attribution by actors, heuristics for the abduction of plausible outcome pathways, or a four-stage Argument and Decision-Tree to assess the credibility of ESG-LM claims (based on Bayes Theorem). My assessment of the entire methodology is positive overall, as it provides solutions to each of the three research areas. Limitations of the approach, and thus opportunities for further research, are the additional expertise and time required by analysts compared to the existing, and somewhat more pragmatic, solutions in the current market. However, this is outweighed in my opinion by the ability of the framework to strongly mitigate impact washing by actors in the financial markets as well as biases by analysts. Its overall methodology also provides opportunities for new research angles in the area of sustainability indicators and assessments.

Beschreibung: This article investigates the event-triggered adaptive containment control problem for a class of stochastic nonlinear multiagent systems with unmeasurable states. A stochastic system with unknown heterogeneous dynamics is established to describe the agents in a random vibration environment. Besides, the uncertain nonlinear dynamics are approximated by radial basis function neural networks (NNs), and the unmeasured states are estimated by constructing the NN-based observer. In addition, the switching-threshold-based event-triggered control method is adopted with the hope of reducing communication consumption and balancing system performance and network constraints. Moreover, we develop the novel distributed containment controller by utilizing the adaptive backstepping control strategy and the dynamic surface control (DSC) approach such that the output of each follower converges to the convex hull spanned by multiple leaders, and all signals of the closed-loop system are cooperatively semi-globally uniformly ultimately bounded in mean square. Finally, we verify the efficiency of the proposed controller by the simulation examples.

Beschreibung: This paper presents a study on the predefined-time (PdT) and practical PdT synchronization of competitive neural networks (CNN) in the presence of different time scales and external disturbances. Two types of external disturbances, which satisfy Lipschitz or bounded conditions, are investigated respectively. The new PdT and practical PdT stability theorems are derived in singularly perturbed systems, where the final residual set is given in detail. By employing the newly derived stability theorems, novel autonomous controllers are designed without relying on a continuous linear term and time scale parameters, while enabling PdT or practical PdT synchronization for drive-response CNNs. Additionally, upper bounds for the settling time are estimated, allowing for adjusting the predefined synchronization times regardless of the initial conditions. Finally, numerical simulations are conducted to demonstrate the effectiveness of the main results.

Beschreibung: The evolution of the Antarctic Ice Sheet is of vital importance given the coastal and societal implications of ice loss, with a potential to raise sea level by up to 58 m if melted entirely. However, future ice-sheet trajectories remain highly uncertain. One of the main sources of uncertainty is related to nonlinear processes and feedbacks of the ice sheet with the Earth System on different timescales. Due to these feedbacks and the ice-sheet inertia, ice loss may already be triggered in the next decades and then unfolds delayed on multi-centennial to millennial timescales. This committed Antarctic sea-level contribution is not reflected in typical sea-level projections based on mass balance changes of Antarctica, which often cover decadal-to-centennial timescales. Here, using two ice-sheet models, we systematically assess the multi-millennial sea-level commitment from Antarctica in response to warming projected over the next centuries under low- and high-emission pathways. This allows bringing together the time horizon of stakeholder planning with the much longer response times of the Antarctic Ice Sheet. Our results show that warming levels representative of the lower-emission pathway SSP1-2.6 may already result in an Antarctic mass loss of up to 6 m sea-level equivalent on multi-millennial timescales. This committed mass loss is due to a strong grounding-line retreat in the Amundsen Sea Embayment as well as a potential drainage from the Ross Ice Shelf catchment and onset of ice loss in Wilkes subglacial basin. Beyond warming levels reached by the end of this century under the higher-emission trajectory SSP5-8.5, a collapse of the West Antarctic Ice Sheet is triggered in the entire ensemble of simulations from both ice-sheet models. Under enhanced warming, next to the marine parts, we also find a substantial decline in ice volume of regions grounded above sea level in East Antarctica. Over the next millennia, this gives rise to a sea-level increase of up to 40 m in our experiments, stressing the importance of including the committed Antarctic sea-level contribution in future projections.

Beschreibung: Detection of critical slowing down (CSD) is the dominant avenue for anticipating critical transitions from noisy time-series data. Most commonly, changes in variance and lag-1 autocorrelation [AC(1)] are used as CSD indicators. However, these indicators will only produce reliable results if the noise driving the system is white and stationary. In the more realistic case of time-correlated red noise, increasing (decreasing) the correlation of the noise will lead to spurious (masked) alarms for both variance and AC(1). Here, we propose two new methods that can discriminate true CSD from possible changes in the driving noise characteristics. We focus on estimating changes in the linear restoring rate based on Langevin-type dynamics driven by either white or red noise. We assess the capacity of our new estimators to anticipate critical transitions and show that they perform significantly better than other existing methods both for continuous-time and discrete-time models. In addition to conceptual models, we apply our methods to climate model simulations of the termination of the African Humid Period. The estimations rule out spurious signals stemming from nonstationary noise characteristics and reveal a destabilization of the African climate system as the dynamical mechanism underlying this archetype of abrupt climate change in the past.