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Institut
- Fakultät Nachhaltigkeit (128) (entfernen)
Fire plays an important role in the earth system by influencing ecosystems and climate, but climate in turn also influences fire. The system became more complex when humans started using fire as a tool. Understanding the interaction between humans, fire and climate is the major aim of paleofire research. Understanding changes in these three aspects in the past will help predicting future climate, fire and human interactions. The use of lake sediment cores as natural archives for reconstructing past fire activity by counting charcoal particles is well established. This present dissertation is dedicated to the evaluation and application of specific organic molecular markers for biomass burning: levoglucosan, mannosan and galactosan were used as proxies for reconstructing past fire activity in lake sediments thorough the entire Holocene. First, a new analytical method was developed using high-performance anion exchange chromatography combined with mass spectrometry to separate and detect these three monosaccharide anhydrides in lake sediments. The suitability of this analytical method was proven by comparing the levoglucosan, mannosan and galactosan results in selected lake sediment samples from Lake Kirkpatrick, New Zealand and by correlating the results with macroscopic charcoal. Furthermore, the method was successfully applied to a lake sediment core from Lake Petén Itzá, Guatemala to reconstruct regional Holocene fire history. The analyses of levoglucosan were combined with fecal sterols to reconstruct late Holocene human fire interactions at Lake Trasimeno, Italy, demonstrating low fire activity during the Roman period. This combination of studies proves that these molecular markers are valid fire proxies in sediments from multiple locations around the globe. Comparison of levoglucosan, mannosan and galactosan concentrations with macroscopic charcoal trends in Lake Kirkpatrick and Lake Petén Itzá, suggests that the molecular markers represent more regional fire history and low temperature fires in contrast to macroscopic charcoal, which is a local fire proxy. In addition, vegetation changes (Lake Kirkpatrick and Lake Petén Itzá) and charcoal morphotypes (Lake Petén Itzá) were compared to the levoglucosan/mannosan and levoglucosan/(mannosan+galactosan) ratios suggesting that these ratios may be a suitable tool to track burned fuel. Biodegradation tests demonstrate the potential degradation of levoglucosan, mannosan and galactosan if dissolved in water, but findings in ancient sediment samples suggest that particle-bound levoglucosan, mannosan and galactosan can be buried in sediments over millennial time scales. Although uncertainties still exist, the results of this research suggests that organic molecular markers are a suitable regional fire proxy and isomer ratios may help understand changes in burned vegetation.
Poor quality of freshwaters is a widespread problem. The concept of complexity is a particularly promising concept to analyse and address this problem, and public policy problems more generally. The main reason is the concept's strength in unifying structural features of problems within a more comprehensive structural approach to political problem-solving. So far, however, these possible benefits remained hidden given the lack of a clear understanding of complexity, ultimately hampering a systematic analysis of the implications of complexity for solutions and governance strategies. This study aims at strengthening the value of the concept of complexity for systematic comparative analyses of water-related problems and public policies in general. To achieve this goal, this work is to specify the concept of complexity as well as the implications of complexity for solutions and governance strategies, both from a theoretical and an empirical point of view. To this end, five main basic approaches are applied, referring to underlying premises, the role of an interdisciplinary approach, the European Water Framework as an empirical reference point, the integration of practical knowledge, and the focus on external validity. This dissertation provides a detailed operationalisation of complexity related to the dimensions of goals, variables, dynamics, interconnections, and informational uncertainty. It also shows that freshwater pollution-related problems in Germany differ along these five complexity dimensions. This applies to 37 types of pollution-related problems and four clusters of problems, which refer here to tame, wicked, system complexity, and uncertainty problems. This dissertation suggests that relations between complexity and policy delivery can be both positive and negative and vary along dimensions of complexity and policy delivery. Regarding the analysed freshwater pollution problems, this work also shows various effects of complexity on policy delivery, both along the 37 types of problems, and along four clusters of wicked problems. This dissertation suggests a differentiated theoretical approach to define governance for complex problem-solving, demonstrating that the role of diverse institutions, actors, and interactions differs for solutions along five key dimensions of complexity and different management strategies that are information gathering, modelling, using decision-support tools, prioritising of measures, conflict solving, deciding under uncertainty, and being adaptive and flexible.
Global climate change and environmental degradation are largely caused by human activity, thus progress towards a sustainable future will require large-scale changes to human behavior. Human-nature connectedness (HNC) - a measure of cognitive, emotional, spiritual and biophysical linkages to natural places - has been identified as a positive predictor of sustainability attitudes and behaviors. While calls to "reconnect to nature" in order to foster sustainability outcomes have become common across science, policy and practice, there remains a great deal of uncertainty, speculation, and conceptual vagueness around how this ought to be implemented. The overarching aim of this thesis is to advance conceptual and empirical understandings of HNC as a leverage point for pro-environmental outcomes and sustainability transformation. In particular, the thesis attempts to assess the nuances of the HNC-PEB (pro-environmental behavior) relationship by investigating the scalar relationships between where someone feels connected to nature and where someone acts pro-environmentally. This research was conducted through conceptual exploration, systematic literature reviews using hierarchical cluster analysis, and empirical case studies relying on structural equation modeling and two-step cluster analysis. The relationship between HNC and pro-environmental attitudes and behaviors was investigated in a small microregion of Transylvania, Romania, where traditional relationships with the land and changing socio-economic characteristics provided an interesting case study in which to explore these connections. The key findings can be organized into three sections: Section A, which addresses HNC and its potential for sustainability transformation; Section B, which addresses HNC as a determinant of PEB outcomes, and Section C, which explores the relationships between human-nature connectedness and energy conservation norms, attitudes, and behaviors. Results cumulatively suggest that HNC is a multidimensional construct that requires greater integration across heterogeneous disciplinary and methodological boundaries in order to reach its potential for meaningful sustainability transformation. Results also highlight the critical need to adopt systemic approaches to understanding how interactions between human-nature connections, norms, attitudes, and behaviors are hindering or promoting sustainability outcomes.
This doctoral dissertation aims to contribute to clarification of the potential of learning for water governance. The goal is to trace and understand the environmental impacts of learning through participation (research aim 1) and adaptive management (research aim 2), and the effect of learning on participation as a governance mode (research aim 3). For this goal, the researcher engages in a predominantly qualitative research design following the case study method. For every specific research aim cases are selected and analysed qualitatively according to conceptual categories and mechanisms which are defined beforehand. Quantitative studies are used to corroborate the results for research aim 1 and 2 in a mixed-method approach to enhance the validity of results. The empirical research context is European water governance, the implementation of the EU Water Framework and EU Floods Directive (WFD, FD) specifically. Eight cases of participatory decision-making across three European countries and five cases of adaptive management in Northern Germany for WFD implementation are examined to identify whether learning in these processes enhanced environmental outcomes. To detect whether governance learning by public officials occurred, the design of participatory processes for FD implementation in ten German federal states is assessed. The findings of research aim 1, understanding learning through participation and its effects on water governance, reveal that participatory planning led to learning through improved understandings at an individual and group level. Learning did, however, hardly shape effective outcomes. In the AM cases (research aim 2) managers and participants of implementing networks improved their knowledge as well as capacities, and spread the results. Nonetheless, environmental improvement was not necessarily linked to ecological learning. Regarding learning about participation as a governance mode (research aim 3) all interviewed public officials in German federal states reported some degree of governance learning, which emerged not systematically but primarily drawing on own experiences and intuition. These findings are condensed into three overarching lessons for learning in water governance: (1) Interactive communication seems to form the overall frame for participant and group learning. Framing of learning experiences turned out to play an important and potentially distorting role, for which professional facilitation and structured knowledge aggregation methods might be an im-portant counterbalance. (2) Learning did not automatically enhance environmental outcomes. It may thus not be an explanatory variable for policy outcomes, but a conditioning or intervening variable related to collective action, motivation for participation, and situating the issue at hand at wider societal levels. (3) The concepts of puzzling and powering might help understand learning as a source for effectiveness in the long-term when complemented with interest-based debates for creat-ing sufficient political agency of policy issues. Learning seen as puzzling processes might instruct acceptance and legitimization for new powering efforts. The perpetuation of learning in systematic ways and structures appears to characterize an alternative to this reflexive and strategic interplay, for which the water-related EU directives provide the basis.
TIME for REFL-ACTION: Interpersonal Competence Development in Project-based Sustainability Courses
(2021)
This dissertation investigates interpersonal competence development in project-based sustainability courses. Visions of a sustainable, safe, and just future cannot be reached by one individual alone. Thus, future change agents need to be able to collaborate and engage with stakeholders, to approach the manifold crises, challenges, problems, and conflicts we are facing together, and to promote and push forward sustainability transitions and transformations. Therefore, this research investigates three project-based sustainability graduate courses by comparing and contrasting teaching and learning outcomes, processes, and environments. A comparative case study approach using a Grounded Theory-inspired research design which triangulates several qualitative methods and perspectives is applied to allow for generalizable insights. Thereby, this dissertation provides empirically-informed insights which are further discussed in relation to selected teaching and learning theories. This leads, first, to a discussion of practical implications within (and beyond) sustainability higher education; and second, provides a theoretical foundation for interpersonal competence development in project-based learning settings – so that educating future change agents can gain momentum. Findings of this research show that embracing conflicts when they occur (i.e. before they provoke cascading effects in the form of further conflicts down-the-road) is an effective strategy to help further develop interpersonal competence. This requires a conflict-embracing attitude. Attitude, in general, seems to be key in interpersonal competence and competence development overall. Self-reflection, if not explicitly required by outside influences (such as instructors), arises naturally from a self-reflective attitude, and is shown to provide the basis for developing interpersonal competence. This research introduces the term "Refl-Action" which stresses the importance of pairing "learning by doing" (as is often the focus in project-based learning settings) with conscious moments of "reflecting about the doing". More specifically, the research presented here identified four learning processes for interpersonal competence development: receiving input, experiencing, reflecting, and experimenting. Based on the empirical data, when the four processes are purposefully combined, following a meaningful sequence attitudes, knowledge, and skills in collaborative teamwork and impactful stakeholder engagement, are fostered (two facets of interpersonal competence). Each of the four learning processes is set in motion through various interactions students engage in during project-based sustainability courses: student-student (labeled "peer"), student-instructor (labeled "deliberate"), student-stakeholder (labeled "professional"), and student-mentor (labeled "supportive") interactions. When these interactions are made explicit subjects of inquiry - i.e. the (inter-)action is linked with (self-)reflection – different learning processes complement one another: Interpersonal competence facets (collaborative teamwork and impactful stakeholder engagement) and domains (attitudes, knowledge, skills) are fostered. While, overall, interactions, processes, and conflicts have been identified as supportive for interpersonal competence development, trust has emerged as another variable inviting further investigation.
Thermal energy storage systems have a high potential for a sustainable energy management. Low temperature thermochemical energy stores based on gas-solid reactions represent appealing alternative options to sensible and latent storage technologies, in particular for heating and cooling purposes. They convert heat energy provided from renewable energy and waste heat sources into chemical energy and can effectively contribute to load balancing and CO2 mitigation. At present, several obstacles are associated with the implementation in full-scale reactors. Notably, the mass and heat transfer must be optimized. Limitations in the heat transport and diffusions resistances are mainly related to physical stability issues, adsorption/desorption hysteresis and volume expansion and can impact the reversibility of gas-solid reactions. The aim of this thesis was to examine the energy storage and cooling efficiency of CaCl2, MgCl2, and their physical salt mixtures as adsorbents paired with water, ethanol and methanol as adsorbates for utilization in a closed, low level energy store. Two-component composite adsorbents were engineered using a representative set of different host matrices (activated carbon, binderless zeolite NaX, expanded natural graphite, expanded vermiculite, natural clinoptiolite, and silica gel). The energetic characteristics and sorption behavior of the parent salts and modified thermochemical materials were analyzed employing TGA/DSC, TG-MS, Raman spectroscopy, and XRD. Successive discharging/charging cycles were conducted to determine the cycle stability of the storage materials. The overall performance was strongly dependent on the material combination. Increase in the partial pressure of the adsorbate accelerated the overall adsorbate uptake. From energetic perspectives the CaCl2-H2O system exhibited higher energy storage densities than the CaCl2 and MgCl2 alcoholates studied. The latter were prone to irreversible decomposition. Ethyl chloride formation was observed for MgCl2 at room and elevated temperatures. TG-MS measurements confirmed the evolution of alkyl chloride from MgCl2 ethanolates and methanolates upon heating. However, CaCl2 and its ethanolates and methanolates proved reversible and cyclable in the temperature range between 25°C and 500°C. All composite adsorbents achieved intermediate energy storage densities between the salt and the matrix. The use of carbonaceous matrices had a heat and mass transfer promoting effect on the reaction system CaCl2-H2O. Expanded graphite affected only moderately the adsorption/desorption of methanol onto CaCl2. CaCl2 dispersed inside zeolite 13X showed excellent adsorption kinetics towards ethanol. However, main drawback of the molecular sieve used as supporting structure was the apparent high charging temperature. Despite variations in the reactivity over thermal cycling caused by structural deterioration, composite adsorbents based on CaCl2 have a good potential as thermochemical energy storage materials for heating and cooling applications. Further research is required so that the storage media tested can meet all necessary technical requirements.
The research described in this dissertation focuses on developing a process to remove oligomers and suppress their formation by intercepting the aging procedure's precursors using adsorbents when biodiesel and its blends are used as fuel. So far, there has been no attempt to cause the stabilization of biodiesel and its blends using adsorbents from open literature. This investigation is one of the first studies on the use of adsorbents to mitigate biodiesel and diesel fuel's stability behavior–biodiesel blends and the removal of oligomers or suppressing the formation of high molecular mass species in aging oil. This study's primary aim has been achieved by several experimental measurements that provided results on adsorbents' effecton fuel oxidative stability, especially ester-based fuel like biodiesel and its blends. The chemical composition and some critical rheological analyses of the samples have been measured to understand their role in the oxidation of the sample by comparing the presence and absence of the adsorbents during the aging process. Furthermore, it aims to use adsorbents to suppress oligomers' formation and remove them in aging oil due to the influence of biodiesel and its blends. The research project also seeks to stabilize fuel, especially ester-based fuel like biodiesel, and its blends using the adsorbents. The adsorbents' application will enhance biodiesel's oxidative stability and its blends during long-term storage or application, focusing on its use in plug-in hybrid vehicles, emergency power plants,and generators. The combustion engine only starts in plug-in hybrid vehicles if the battery cannot supply energy on longer journeys. As a result, the fuel remains longer in plug-in hybrid vehicles. Fuels that are exposed to heat and oxygen over anextendedperiod can form aging products. These aging products lead to the formation of deposits, especially in the case of diesel fuels mixed with biodiesel content,and can, therefore, endanger the operational safety of the vehicle in critical components such as injectors or filter units.
Agricultural production of smallholder farmers in Myanmar is facing soil fertility degradation and in consequence, crop yields decline due to the imbalances of nutrient supply. In most cases, all above ground biomass is removed from the fields after harvesting the crops and during land preparation for the next crop. Higher temperatures also stimulate the higher mineralisation rates and released mineral nutrients are lost from fallow lands before sowing the next crops. Regarding the addition of mineral fertilizers, except for cash crops, farmers are reluctant to apply fertilizers for the crops that are sown for household’s self-sufficiency. In the Dry Zone, irrigated agriculture is available in recent years and farmers could overcome water scarcity through irrigation. With the availability of irrigation water, farmers could prolong the cropping period, nevertheless crop yields are decreasing year by year. In recent decades, research findings are indicating the benefits of biochar application for soil fertility improvement and food security. Smallholder farmers can produce biochar from agricultural by-products such as pigeon pea stems, cotton stems and rice husks by using biochar stoves. Large-scale production is possible by producing both biochar and thermal energy simultaneously, such as getting rice husk biochar and producing thermal energy by burning rice husks. By those means, environmental pollution due to the smokes from stubble burnings and the health hazards from smokes arise from kitchens can also be reduced. Present research was conducted to test the effects of the application of biochars produced from different crop residues together with NPK fertilizers on crop yields and soil properties in the rice-chickpea-cotton cropping system of the Central Dry Zone area of Myanmar during 2012 and 2013 cropping seasons at Shwe Daung Farm, Mandalay Division, Myanmar. Effects of biochar applications in combination with NPK fertilizers were compared with NPK fertilizer (without biochar) application and the control (without biochar and NPK fertilizers). Biochars used in the experiments were produced from three kinds of locally available raw materials (rice husk, rice straw and, pigeon pea stem) at temperature above 550°C by using a kiln made from a 200-Liter diesel barrel. Field experiments were conducted on sandy loam soil in the Central Dry Zone of Myanmar. After harvesting rice in 2012, chickpea was sown without application of both organic and inorganic fertilizers. After harvesting chickpea in 2013, cotton was sown on the same experimental plots. Treatments were rice husk biochar (Rh) 20 Mg ha-1 + NPK fertilizers; rice straw biochar (Rs) 20 Mg ha-1 + NPK fertilizers; pigeon pea stem biochar (Ps) 20 Mg ha-1 + NPK fertilizers; rice husk biochar and farmyard manure mixture (Rh biochar + FYM) 10 Mg ha-1 + NPK fertilizers; NPK fertilizers (without biochar); and the control (without fertilizer and biochar). Biochar weights represented fresh biochar weights. Equal rate of NPK fertilizers were applied in all treatments. However, fertilizer rates were different with respect to the crops. In rice experiment, 100:50:50 kg ha-1 rate of Urea (N): Triple Super Phosphate (P): Muriate of potash (K) was applied. In cotton experiment, 100:30:117 kg ha-1 rate of Urea (N): Triple Super Phosphate (P): Muriate of potash (K) was applied. Crop growth data, yield component data and yield data of each treatment were recorded. Soil samples from topsoil (0-0.2 m) were taken before starting the experiments, after harvesting rice and cotton, respectively, and analysed. A biogeochemical model, denitrification decomposition (DNDC) model, was used to estimate soil organic carbon storage and greenhouse gas emissions during crop growing seasons and to quantify the long-term impact of biochar applications on rice, chickpea and cotton yields.The results from soil analyses indicated that although initial soil pH was at 8.0 and pH values of biochars ranged between 8.0 and 10.0 soil pH after two years of biochar application did not increase. pH values were below 8.0. That value was lower than initial soil pH. That could be due to the effect of the change of cropping system from upland to lowland rice cultivation and the effects of biochar additions to the alkaline sandy loamy soil of the experimental site. Although total exchangeable cation value was not significantly different among the treatments, compositions of major cations were significantly different among the treatments. Exchangeable potassium increased in Rs biochar + NPK applied soils. Exchangeable sodium increased in control, and conventional NPK fertilizer applied soils. Reduction of soil bulk density from 1.8 g cm-3 to 1.6-1.7 g cm-3 occurred in biochar treatments compared to control and conventional NPK fertilizer application treatments. Positive changes of total carbon and total nitrogen of soils were found in biochar treatments compared to control and conventional NPK fertilizer application. Application of pigeon pea stem biochar + NPK fertilizers showed the highest crop growth and the highest yield in rice. The highest chickpea yield was obtained from the plot that applied rice husk biochar + NPK fertilizers. Cotton crop growth and yield was the highest in rice husk biochar and farmyard manure mixture + NPK fertilizer application. The lowest crop growth and yield was obtained from the control in cotton. The results of this study suggested that biochars from different biomass materials had different effects on soil properties and crop yields under different growing conditions and cultivated crops. Although the applied biochars had a high pH, soil pH did not increase after biochar applications. The growth and yield of tested crops were higher than that of the control and conventional NPK fertilizer application. Rice husk biochar and farmyard manure mixture + NPK fertilizer application can be assumed as a suitable soil amendment application under upland crop cultivation. Pigeon pea stems biochar + NPK fertilizers should be applied in rice cultivation. Rice husk biochar + NPK fertilizers and rice husk biochar-farmyard manure mixture + NPK fertilizers showed as the appropriate biochar soil amendments for the study area compared to rice straw biochar + NPK fertilizers and pigeon pea stem biochar + NPK fertilizers. Application of these biochars increased total exchangeable cations, reduced bulk density, increased organic carbon, regulated soil pH and, can easily be accessed by smallholder farmers by promising crop yields for sustainable agricultural production. Rice straw biochar + NPK fertilizers and pigeon pea stem biochar + NPK fertilizers also showed positive influences on soil fertility and crop growth. However, extensive application of those biochars might require large-scale productions and distributions. To obtain the detail information regarding the impact of biochar application on the agro-ecosystem and surrounding atmosphere, further research activities may need to carry out under different agricultural production conditions. When model fitness was tested, it was found that DNDC model was fit for the simulation of crop yields and soil organic carbon under the conditions of the experimental site. Simulation of soil organic carbon dynamics and crop yields for 30 years and 50 years after the addition of biochars in combination with NPK fertilizers showed that such applications could maintain the crop yields at the same level up to 50 years. That could maintain soil organic carbon at a level higher than conventional NPK fertilizer application. Regarding the simulation of GHGs emissions, the model simulated nitrous oxide emission close to actual emissions of agricultural soils of Myanmar. Simulated CH4 emissions from control and conventional NPK fertilizer application variant were consistent with the well-known emissions of Myanmar rice fields. To confirm the accuracy of simulated CH4 emissions from biochar applied soils, it may need field investigations and validations of model results. Simulated effects of rice husk-, rice straw- and pigeon pea stem fresh biomass applications and that of rice husk-, rice straw- and pigeon pea stem biochar applications on rice, chickpea, cotton yields and soil organic carbon (SOC) were compared. Objective of this simulation was to compare the effects of fresh biomass-applications and the application of biochars produced from the same biomass on crop yields and SOC by using DNDC model. The results showed that simulated rice yields of rice husk biochar and rice straw biochar applications were 33% and 31%, respectively, higher than that of pigeon pea green manure applications. However, simulated rice yield from pigeon pea stem biochar application was 4% higher than that of iv pigeon pea stem green manure application. Simulated chickpea yield from pigeon pea green manure treatment was the highest among all of biochar and biomass applications. Simulated cotton yields obtained from fresh biomass applications were lower than that of biochar applications. In estimating the future yields, all crop yields from rice husk and rice straw biomass applications were lower than that of rice husk and rice straw biochar applications in the initial year of simulation. However, in the following years, the yields remained at the same level up to the end of simulated years. In pigeon pea stem green manure application, crop yields were higher than the other treatments since the initial year up to the end of simulated years. Simulated SOC was lower in fresh biomass applications compared to biochar applications.
Despite growing research on sustainability transformations, our understanding of how transformative transdisciplinary research can support local actors who foster change towards sustainability is still somewhat limited. To contribute to this research question, the investigator conducted research in a transdisciplinary case study in Southern Transylvania, where non-governmental organizations (NGO) drive sustainability initiatives to foster desired changes (e.g., supporting small-scale farmers or conserving natural and cultural heritage). Interactions with these local actors and reflections on the research question shaped the research of this dissertation. In paper 1, the author conducted a literature review on amplification processes that describe actions, which local actors can apply to increase the impact of their sustainability initiatives. In paper 2, he conducted a literature review on the application of indigenous and local knowledge (ILK) in sustainability transformations research to understand whether this research engages with the conceptualization of transformations from local actors. The results show that ILK is generally applied to confirm and complement scientific knowledge in contexts of environmental, climate, social-ecological, and species change. In paper 3, the author derived principles that provide guidance for how to integrate sustainability initiatives from local actors in transformative transdisciplinary research. Based on his transdisciplinary research with the NGOs in Southern Transylvania and by using systems and futures thinking as an approach for analysis, he derived three principles that provide guidance for the co-design of sustainability intervention strategies that build on, strengthen, and complement existing initiatives from local actors. In paper 4, the author explored empirically how to identify relevant local actors for collaborations that seek to intervene in specific characteristics of a system (e.g., parameters or design of a system). He applied a leverage points' perspective to analyse the social networks of the NGOs in Southern Transylvania that amplify the impact of their initiatives. This dissertation as a whole contributes insights to three recommendations of how transformative transdisciplinary research can support local actors fostering change towards sustainability: First, by conducting research that studies and supports local actors who increase the impact of their sustainability initiatives via amplification processes (Paper 1 and 4); Second, by engaging specifically with the initiatives, networks, and knowledge from local actors, who foster bottom-up, place-based transformations (Paper 1-4); Third, by identifying and collaborating with local actors that are relevant for strategic systems interventions that build on, strengthen, and complement existing initiatives (Paper 3-4).
Urban areas are prone to climate change impacts. Simultaneously the world's population increasingly resides in cities. In this light, there is a growing need to equip urban decision makers with evidence-based climate information tailored to their specific context to adequately adapt to and prepare for future climate change. To construct climate information high-resolution regional climate models and their projections are pivotal. There is a need to move beyond commonly investigated variables, such as temperature and precipitation, to cover a wider breath of possible climate impacts. In this light, the research presented in this thesis is centered around enhancing the understanding about regional-to-local climate change in Berlin and its surroundings, with a focus on humidity. More specifically, following a regional climate modelling and data analysis approach, this research aims to understand the potential of regional climate models, and the possible added value of convection-permitting simulations, to support the development of high-quality climate information for urban regions, to support knowledge-based decision-making. The first part of the thesis investigates what can already be understood with available regional climate model simulations about future climate change in Berlin and its surroundings, particularly with respect to humidity and related variables. Ten EURO-CORDEX model combinations are analyzed, for the RCP8.5 emission scenario during the time period 1970-2100, for the Berlin region. The results are the first to show an urban-rural humidity contrast under a changing climate, simulated by the EURO-CORDEX ensemble, of around 6% relative humidity, and a robust enlarging urban drying effect, of approximately 2-4% relative humidity, in Berlin compared to its surroundings throughout the 21st century. The second part explores how crossing spatial scales from 12.5km to 3km model grid size affects unprecedented humidity extremes and related variables under future climate conditions for Berlin and its surroundings. Based on the unique HAPPI regional climate model dataset, two unprecedented humidity extremes are identified happening under 1.5°C and 2°C global mean warming, respectively SH>0.02 kg/kg and RH<30%. Employing a double-nesting approach, specifically designed for this study, the two humidity extremes are downscaled to the 12.5km grid resolution with the regional climate model REMO, and thereafter to the 3km with the convection-permitting model version of REMO (REMO NH). The findings indicate that the convection-permitting scale mitigates the SH>0.02kg/kg moist extreme and intensifies the RH<30% dry extreme. The multi-variate process analysis shows that the more profound urban drying effect on the convection-permitting resolution is mainly due to better resolving the physical processes related to the land surface scheme and land-atmosphere interactions on the 3km compared to the 12.5km grid resolution. The results demonstrate the added value of the convection-permitting resolution to simulate future humidity extremes in the urban-rural context. The third part of the research investigates the added value of convection-permitting models to simulate humidity related meteorological conditions driving specific climate change impacts, for the Berlin region. Three novel humidity related impact cases are defined for this research: influenza spread and survival; ragweed pollen dispersion; and in-door mold growth. Simulations by the regional climate model REMO are analyzed for the near future (2041-2050) under emission scenario RCP8.5, on the 12.5km and 3km grid resolution. The findings show that the change signal reverses on the convection-permitting resolution for the impact cases pollen, and mold (positive and negative). For influenza, the convection-permitting resolution intensifies the decrease of influenza days under climate change. Longer periods of consecutive influenza and mold days are projected under near-term climate change. The results show the potential of convection-permitting simulations to generate improved information about climate change impacts in urban regions to support decision makers. Generally, all results show an urban drying effect in Berlin compared to its surroundings for relative and specific humidity under climate change, respectively for the urban-rural contrast throughout the 21st century, for the downscaled future extreme conditions, and for the three humidity related impact cases. Added value for the convection-permitting resolution is found to simulate humidity extremes and the meteorological conditions driving the three impacts cases.
In der vorliegenden Arbeit wurde ein ICP-QMS mit integrierter Reaktions- /Kollisionszelle erfolgreich eingesetzt, um die Elemente Vanadium, Chrom, Mangan, Eisen, Nickel, Kobalt, Kupfer, Zink, Arsen, Molybdän, Cadmium, Blei und Uran direkt in verdünntem Meerwasser zu bestimmen. Die Bestimmung von Elementspuren in Meerwasser wurde realisiert, indem alle zur Verfügung stehenden Möglichkeiten zur Minimierung von Interferenzen bei der Bestimmung von Elementen mit ICP-QMS angewendet wurden.
Der hohe Verbrauch von Antibiotika führt zu stetig steigenden Konzentrationen der Wirkstoffe und ihrer Transformationsprodukte in der Umwelt. Antibiotika in der Umwelt haben das Potential Funktionen von Ökosystemen zu stören und tragen zur Entwicklung und Selektion von resistenten Bakterien bei. Um diese negativen Auswirkungen auf Mensch und Umwelt zu reduzieren, sind vielseitige Lösungen notwendig. Benign by Design (BbD) ist ein wichtiger Baustein dafür. Daher ist es wichtig zu verstehen, inwiefern das BbD Prinzip auf verschiedene Substanzgruppen anwendbar ist und welche Limitierungen zu berücksichtigen sind. Mit dieser Arbeit soll ein Beitrag zur Entwicklung von in der Umwelt mineralisierbaren Antibiotika entsprechend des Benign by Design Konzeptes geliefert werden. Dies wurde am Beispiel der Fluorchinolonantibiotika durchgeführt, da diese sehr wichtige, aber auch sehr persistente Wirkstoffe sind. Ziel war es, zu verstehen, welche Veränderungen an der Grundstruktur vorgenommen werden können, um Derivate zu erzeugen, die während der Wirkdauer und Lagerung ausreichend stabil bleiben, aber anschließend in der Umwelt möglichst schnell und vollständig mineralisiert werden können. Im ersten Teil der Arbeit wurden die BbD Ansätze des targeted und non-targeted Re-Designs und de novo Designs, sowie die Verwendung von in silico Tools zu deren Umsetzung, untersucht. Basierend darauf wurde ein Workflow entwickelt, der eine mögliche Verwendung von computergestützten Methoden innerhalb des BbD Frameworks aufzeigt. Der Ansatz des non-targeted Re-Designs wurde für neun verschiedene Substanzen aus der Klasse der Fluorchinolone angewandt. Dafür wurden Transformationsprodukte der Muttersubstanzen mittels Photolyse und Photokatalyse erzeugt. Das resultierende Substanzgemisch wurde hinsichtlich der biologischen Abbaubarkeit und Toxizität untersucht. Es konnte gezeigt werden, dass durch die Bestrahlung mit UV-Licht eine Vielzahl an neuen Strukturen entstehen und das Gemisch oft eine gesteigerte biologische Abbaubarkeit im Vergleich zur Muttersubstanz aufweist. Das targeted Re-Design wurde am Beispiel von Fluorchinolon-Glucosamin-Derivaten untersucht. Dabei galt es zu verstehen, inwiefern Glucosamin-Substituenten die biologische Abbaubarkeit beeinflusst. Es konnte gezeigt werden, dass durch die Verwendung von acetylierten Glucosamin-Substituenten ein partieller Abbau stattfindet. Diese Erkenntnisse können zukünftig in das gezielte, fragment-basierte Design von grüneren Strukturen einfließen. Im letzten Teil der Arbeit wurden die Struktur-Bioabbau-Beziehungen von N-hetero-zyklischen Verbindungen, welche auch die Basis des Fluorchinolon-Grundgerüstes sind, untersucht und leicht biologisch abbaubare Leitstrukturen identifiziert. Dafür wurden 84 verschiedene N-Heterozyklen nach OECD 301 Richtlinien getestet. Basierend darauf wurde zum einen ein lokales 3D-QSAR Modell, insbesondere zur Visualisierung der Effekte der Substituenten im dreidimensionalen Raum, erstellt, als auch Regeln für das Design von umweltfreundlicheren Chinolonen und verwandten Strukturen abgeleitet. Weiterhin wurden abbaubare Strukturen aus der Gruppe der Chinazoline identifiziert, welche vielversprechende Leitstrukturen für das Design von Topoisomerase-Inhibitoren oder anderer Chemikalien darstellen. Insgesamt zeigen die Ergebnisse, dass die Umsetzung von BbD im Wirkstoffdesign möglich ist und wie potentielle Vorgehensweisen aussehen können. Dabei konnte gezeigt werden, dass selbst die als besonders persistent geltenden Fluorchinolonantibiotika das Potential bieten, zu besser abbaubaren Derivaten re-designt zu werden. Es wurde jedoch auch deutlich, dass es keine allgemeingültige Herangehensweise gibt und Methoden den entsprechenden Substanzklassen und Anforderungen angepasst werden müssen.
The German energy system is under transformation. The so-called Energiewende (in English, Energy turn) relies, among other things, on renewable energies for building a more sustainable energy system. Regions (Landkreise) are one relevant level where different administrative bodies make decisions and plans both for the implementation and for the use of renewable energies. However, in order to realize the goals of the Energiewende, developments in the wider society are necessary. This is why scientific research can and should foster such developments with more research on the social aspects of energy-related topics. The present work contributes to the understanding of transition processes towards a sustainable use of regional renewable energy by focusing on the role of contextual conditions, practical experiences, and temporal dynamics in the implementation and use of renewable energy in German regions. In this way, this work wants to contribute fostering the development of regional energy transition strategies for the realization of the Energiewende. The conceptual background for this piece of transformation research lies in three bodies of literature dealing respectively with transitions of socio-technical systems, transformations of socioecological systems, and time ecology. From a critical engagement with this literature, three main results have emerged. First, an evidence-based, spatially distinct analysis of contextual conditions for the use of renewable energy in all German regions has resulted in the identification of nine types of regions, so-called energy context types. Second, empirical research on practices in regional settings learned from the knowhow of actors from regional administration has shown that political and economic conditions are crucial as well as that process management, exchange, and learning are helpful for renewable energy implementation. Third, conceptual work about a deeper understanding of the temporal dimensions of transformation processes has made it possible to point out a three-step approach to include temporal dynamics into sustainability transformations management - the time-in-transformations-approach. The literature suggests that regions need to be treated individually; but developing an energy transition strategy for each region individually would be extremely resource intensive. Overall, this work outlines a compromise for a more efficient approach towards regional energy transition strategies which still considers the individuality of regions. As a result, the author suggests to develop generic regional energy transition strategies that are adapted to each of the nine energy context types of German regions, that include the experiences of practitioners, and that consider temporal dynamics of transformation processes. Transdisciplinary research is a promising approach to meet many of the challenges for the realization of the Energiewende.
This dissertation examines how smallholder farming livelihoods may be more effectively leveraged to address food security. It is based on empirical research in three woredas (districts) in the Jimma Zone of southwestern Ethiopia. Findings in the chapters that follow draw on quantitative and qualitative data. In this research, the author focuses on local actors to investigate how they can be better supported in their roles as agents who have the ability to improve their livelihoods and achieve food security. This general aim is operationalized through three research questions: (i) How do livelihood strategies influence food security?; (ii) What livelihood challenges are common and how do households cope with these?; and (iii) How do social institutions, in which livelihoods are embedded, influence people's abilities to undertake livelihoods and be food secure? Using quantitative data from a survey of randomly selected households, the author applied a number of multivariate statistical analysis to determine types of livelihood strategies and to establish how these strategies are associated with capital assets and food security. Here she views livelihood strategies as a portfolio of livelihood activities that households undertake to make a living. The predominant livelihood in the study area was diversified smallholder farming involving mainly the production of crops. Based on their analyses, the authors found five types of livelihood strategies to be present along a gradient of crop diversity. Food security generally decreased with less crops being part of the livelihood strategy. The livelihood strategies were associated with households' capital assets. The status of food (in)security of each household during the lean season was measured using the Household Food Insecurity Access Scale (HFIAS). A generalized linear model established that the type of livelihood strategy a household undertook significantly influenced their food security. Other significant variables were educational attainment and gender of household head. The findings contribute evidence to the benefits of diversified livelihoods for food security. Smallholder farming in southwest Ethiopia is beset with process-related and outcome-related challenges. Here, a process-related challenge pertains to the lack of different types of capital assets that people need to be able to undertake their livelihoods, while an outcome-related challenge pertains to lack of food. The most frequently mentioned process-related challenges were associated with the natural capital either as lack in necessary ecosystem services or high levels of ecosystem disservices. Farming households typically faced the combined challenges of decreasing soil fertility, land scarcity, die-off of oxen due to diseases, and wild animal pests. Lack of cash was also common. The findings indicate that when households liquidate a physical asset in order to gain cash, the common outcome is an erosion of their capital asset base. On the other hand, when households drew on their social capital, they tended to maintain their capital asset base. Human capital, for example, in the form of available labor was also important for coping. Protecting and enhancing natural capital is needed to strengthen the basis of livelihoods in the study area, and maintaining social and human capitals is important to enable farming households to cope with challenges without eroding their capital asset base. Smallholder farming in southwest Ethiopia is embedded in a social context that creates differentiated challenges and opportunities. Gender is an axis of social differentiation on which many of the differences are based. The currently ruling Ethiopian political coalition has put important policy reforms in place to empower women. Local residents reported notable changes related to gender in the last ten years. To make sense of the changes, the authors adapted the leverage points concept. Using this concept, the authors classified the reported changes as belonging to the domains of visible gaps, social structures, and attitudes. Importantly, changes within these domains interacted. The most prominent driver of the changes observed was the government's emphasis on empowering women and government-organized interventions including gender sensitization trainings. The changes toward more egalitarian relationships at the household level were perceived by local residents to lead to better implementation of livelihoods, and better ability to be food secure. The study offers the insight that while changing deep, underlying drivers (e. g. attitudes) of systemic inequalities is critical, other leverage points such as formal institutional change and closing of certain visible gaps can facilitate deeper changes (e. g. attitudes) through interaction between different leverage points. This can inform gender transformative approaches. While positive gender-related changes have been observed, highly unequal gender norms still persist that lead to women as well as poor men being disadvantaged. Social norms which provide the basis for collective understanding of acceptable attitudes and behaviors are entrenched in people's ways of being and doing and can therefore significantly lag behind formal institutional changes. Norms influenced practices around access and control of capital assets, decision-making, and allocation of activities with important implications for who gets to participate, how, and who gets to benefit. To more effectively leverage smallholder farming for a food secure future, this dissertation closes with four key insights namely: (1) Diversified livelihoods combining food and cash crops result in better food security; (2) Enhancing natural and social capital is a requisite for viable smallholder farming; (3) Social and gender equality are strategically important in improving livelihoods and food security; and (4) Institutions particularly social norms are key to achieving gender and social equality.
The effects of habitat fragmentation and land use changes are usually studied by relating patterns of genetic diversity and differentiation to environmental factors, habitat history, landscape structure, or to a combination thereof. However, these three drivers are rarely addressed simultaneously. In addition, these studies are usually carried out in conservation-driven contexts, and therefore tend to concentrate on hyper-fragmented landscapes and on rare or endangered species. However, how habitat fragmentation and land use affect widespread species in more typical landscapes has not been fully investigated. This thesis addresses these two gaps. Abax parallelepipedus, a flightless ground beetle with low dispersal power, was used as a model species to test how environmental factors, habitat history, and landscape structure affect genetic diversity and genetic differentiation in three study regions located across Germany. Although all of the study regions represent fairly typical rural landscapes for central Europe, each consisting of a complex matrix of land uses, they differ from one another in terms of environmental factors, habitat history, and landscape structure, and thus can serve as three test cases. In the first stage of the work, the investigator identified polymorphic microsatellite loci which could potentially be used to study genetic diversity and differentiation in A. parallelepipedus. She then developed PCR and genotyping protocols for two suites of loci, in the end selecting to use the set of 14 fully multiplexed loci for the study. After having developed the needed study system, she genotyped over 3300 beetles from 142 study sites. In her investigation of how environmental factors and habitat history affect genetic diversity and genetic differentiation, and found that genetic diversity was being driven by variables that could be related to population sizes rather than by habitat history. She also did not find evidence of an influence of habitat history on the genetic differentiation patterns. Although populations of A. parallelepipedus in the past were probably smaller due to deforestation, they apparently remained large enough to prevent rapid genetic drift. In addition, the researcher carried out a landscape genetics analysis of the genetic differentiation patterns found in each of her study regions, in which she examined the relationship between genetic differentiation and landscape structure. She tested whether she could find patterns of isolation by distance, isolation by resistance, or isolation by barriers in the study regions. No effects of land use or of fragmentation were found. Based on the importance of population sizes found in the previous study, combined with the beetle's known avoidance of non-wooded areas and its inability to cross roads, the investigator concludes that although there is probably little gene flow across the study regions, large population sizes are preventing the rapid development of genetic differentiation. Models simulating the development of genetic differentiation over time in populations of different starting sizes support this conclusion.
The timber shortage led to large scale afforestations on previously agriculturally used land in Central Europe during the 19th and 20th century. Widespread afforestation programs created recent forest ecosystems (i.e. young forest systems in terms of their development history). Despite the positive effect of increasing the forest area of Central Europe, the ecological effects of these land-use changes on forest ecosystems remain poorly understood. In order to increase the understanding of ecosystem processes in forests, an assessment of conceivable shifts in ecosystem functions caused by former land-use changes and forest management is required. By analysing aboveground growth rates of European beech (Fagus sylvatica L.) in response to environmental change drivers, such as climate extremes and nitrogen (N) deposition, the presented thesis aims to assess the role of land-use and management legacies in modulating present responses to drivers of environmental change. To this end, annual radial growth rates of individual trees were measured in mature beech stands. The investigated stands differed either in their land-use history (i.e. ancient forest sites versus recent forests) or their forest management history (i.e. managed forest sites versus short-term and long-term unmanaged forest sites). Measurements of radial growth rates were complemented by analyses of the fine root systems, soil chemical properties and crown projection areas to gain insights into the mechanisms underlying alterations in tree growth. Within the projects of the presented thesis, shifts in the climate-growth relationships driven by land-use and management legacies were analysed. In addition, land-use legacy mediated differences in the climate-nitrogen-growth relationships were assessed. The key findings are: (I) Soil legacy driven alterations in the fine root systems cause a higher sensitivity of radial increment rates to water deficits in summer for trees growing on recent forest sites than for trees growing on ancient forest sites. (II) Management legacies (in terms of tree release) enhance the sensitivity of beech’s radial growth to water deficits in spring through changes in crown sizes. (III) Interacting effects of spring water deficits and co-occurring high deposition of reactive N compounds lead to stronger radial growth declines in trees growing in ancient forests. This is likely caused by resource allocation processes towards seed production, which is, in turn, mirrored by decreasing radial growth rates. In this context, high N deposition likely boosts mass fructification in beech trees. Overall, it has been demonstrated that the ecological continuity plays a crucial role in modulating both climate sensitivity and the growth response to interacting effects of water deficits and nitrogen deposition in beech trees. The presented thesis identified a trade-off between the climate sensitivity and maximised growth rates within beech trees, depending on forest history. The results show that the growth of beech in ancient, unmanaged beech forests is less sensitive to water deficits than in recent and managed beech forests. Additionally, interacting effects of spring water deficits and N deposition likely increase the reproductive effort of beech trees, particularly in ancient forests. Thus, the results of this thesis once again underpin the uniqueness of ancient, unmanaged beech forests, whose importance for the conservation of biodiversity has been widely acknowledged. In summary, the presented thesis highlights the need to consider the "ecological memory" of forest ecosystems when predicting responses to current and future environmental changes.
Das ubiquitäre Vorkommen von Arzneimittelrückständen ist eng mit möglichen Risiken für Mensch und Umwelt verbunden. Das übergeordnete Ziel dieser Forschungsarbeit ist die Weiterentwicklung methodischer Ansätze für die Identifizierung prioritärer Arzneimittelrückstände vor dem Hintergrund bestehender Wissens- und Regulierungslücken. Unter diesem Gesichtspunkt wurden drei aktuelle Problemfelder aus dem Themenkomplex "Arzneimittel in der Umwelt " ausgewählt und anhand konkreter Fallbeispiele betrachtet. Tierarzneimittel werden häufig mit der Ausbringung von Wirtschaftsdünger in landwirtschaftlich genutzte Böden eingetragen. Gegenstand der ersten Publikation ist die Frage, inwiefern Anwendungsschemata aus der Nutztierhaltung für die retrospektive Identifizierung prioritärer Tierarzneimittelrückstände genutzt werden können. Hierzu wurde eine spezielle Herangehensweise entwickelt und am Beispiel von Antibiotika erprobt. Die durchgeführte Eintragsabschätzung ermöglichte erstmalig eine umfassende Einschätzung der potenziellen Antibiotikabelastung in Wirtschaftsdünger und landwirtschaftlich genutzten Böden im nordwestdeutschen Raum. Die Ergebnisse deuten auf erhebliche Umwelteinträge hin, die eine Neubewertung bestehender Wirkstoffzulassungen notwendig erscheinen lassen. In der zweiten Publikation wurden am Beispiel einer Mischung aus 18 Arzneistoffen verschiedene Bewertungsansätze verfolgt, um das Risiko einer kombinierten antimikrobiellen Wirkung genauer zu charakterisieren und prioritäre Mischungsbestandteile zu identifizieren. Das Risiko einer antimikrobiellen Wirkung wurde sowohl durch eine experimentelle Prüfung der Mischung als auch durch einen komponentenbasierten Berechnungsansatz bestätigt. Der komponentenbasierte Ansatz verdeutlichte zudem die besondere Relevanz der in der Mischung enthaltenen Fluorchinolon-Antibiotika. Die notwendige Grundlage für eine belastbare Abschätzung von Kombinationseffekten sind jedoch harmonisierte Einzelstoffdaten, die bisher nicht im benötigten Umfang zur Verfügung stehen. Deshalb sollte speziell für Antibiotika eine systematische Prüfung der Wirkung auf Umweltmikroorganismen durchgeführt werden. Arzneistoffe können entlang ihres Lebenszyklus verschiedene biotische und abiotische Transformationsprozesse durchlaufen, die oft zur Bildung von unvollständig charakterisierten Transformationsprodukten (TPs) führen. Die Publikationen 3-7 leisten einen allgemeinen Beitrag zur Einschätzung des möglichen Gefahrenpotenzials von pharmazeutischen TPs im Wasserkreislauf und generieren neue methodische Erkenntnisse vor dem Hintergrund einer vorausschauenden Identifizierung von prioritären Abbauprodukten. Die durchgeführten Fallstudien bestätigten, dass photochemische Transformationsprozesse nicht nur zur Abschwächung bereits vorhandener, sondern im Gegenteil auch zur Entstehung gänzlich neuer Gefahrenpotenziale beitragen können. Es ist somit stark in Frage zu stellen, ob die alleinige Fokussierung auf bekannte Aktivitäten der Muttersubstanz für eine sichere Bewertung von TPs ausreicht.
Both sustainability and transdisciplinary research can change academic research, especially with regard to its relevance for, and relationship with, its environments. Transdisciplinary sustainability research (TSR), thus, offers the opportunity to change non-sustainable development paths of sciences themselves. In order to fully exploit this possibility, this PhD project addresses the question of how TSR, in the first place, does conceptualize and, in the second place, could conceptualize knowledge, research, and science. Firstly, this PhD project analyzes, from a discourse studies perspective, the term problem in TSR, against the background of discourses on sustainable development. Secondly, it explores the historical-analytical and transformative concept of the problematic. The results, firstly, show the consequences of a problem-solving focus for TSR, and secondly, differentiate it from a transformative direction of problematic designing, as a more appropriate view on the dimensions of transformation and their qualities of change that matter for TSR. This PhD project aims to contribute to a self-understanding of, and a philosophical communication about, TSR, as a research form in the sustainability sciences.
A solid knowledge about nature is essential to understand the consequences of biodiversity loss, the limitation of natural resources and the need for a sustainable development. Inspired by these challenges, the researcher investigated in her dissertation seed predation, an important ecosystem function, as part of citizen science project. As seed predation has only rarely been investigated along urban-rural gradients and to integrate the question if the background (urban vs. rural) of primary school children affects their environmental knowledge, she selected study sites in and around Lüneburg and Hamburg, in Northern Germany. In her ecological experiments, it was found that slugs are important seed predators that independently of urbanization predated about 30% of all seeds in the anthropogenically used landscapes investigated. Also, for the first time, primary school children could be integrated in a citizen science approach into this research and it could be shown that even seven year old children can record data as reliable as a scientist. Finally, the researcher investigated the native species knowledge from the children taking part as citizen scientists in her research, considering possible differences due to their urban or rural background. Contrary to her expectation, the urban or rural background had no significant effect on the species knowledge. However, the work provides a good foundation to transfer the approach of introducing a basic foundation of a taxonomical species concept in primary school to foster further understanding on biodiversity and ecosystem functions.
The dissertation project focuses on empirically investigating consumers' attitudes, motivations and purchasing decisions regarding sustainable products. The focus on this micro perspective, however, does not reflect consumers' roles within the transformation towards sustainable consumption. Therefore, the present framework paper puts the included papers into a greater context and evaluates the findings on a meta-level by applying an enhanced transition management theory. The analysis underlines that consumers' limited personal capabilities are an underlying reason for unsustainable practices. Therefore, the active engagement not only of consumers, but also of companies is required if the transformation is to be successful. If companies actively support consumers in making sustainable choices, consumers can engage in sustainable consumption with only low cognitive efforts. On this basis, genuine sustainable choices are enabled. The dissertation provides practical implications by highlighting potential measures which will help to promote sustainable products from niches to mainstream. In sum, the dissertation project enhances academic understanding of consumers´ sustainable purchasing behavior and reveals the potential of integrating such insights into the management of transformations towards sustainable consumption.