Refine
Document Type
- Part of Periodical (8)
- Working Paper (5)
- Doctoral Thesis (3)
- Article (2)
Has Fulltext
- yes (18) (remove)
Is part of the Bibliography
- no (18) (remove)
Keywords
- Climate Change (18) (remove)
Institute
- Sustainable Architecture for Finance in Europe (SAFE) (12)
- Wirtschaftswissenschaften (12)
- Center for Financial Studies (CFS) (4)
- House of Finance (HoF) (4)
- Biowissenschaften (1)
- Exzellenzcluster Die Herausbildung normativer Ordnungen (1)
- Geowissenschaften (1)
- Geowissenschaften / Geographie (1)
- Rechtswissenschaft (1)
We develop a two-sector incomplete markets integrated assessment model to analyze the effectiveness of green quantitative easing (QE) in complementing fiscal policies for climate change mitigation. We model green QE through an outstanding stock of private assets held by a monetary authority and its portfolio allocation between a clean and a dirty sector of production. Green QE leads to a partial crowding out of private capital in the green sector and to a modest reduction of the global temperature by 0.04 degrees of Celsius until 2100. A moderate global carbon tax of 50 USD per tonne of carbon is 4 times more effective.
Seed dispersal is a key ecosystem function for plant regeneration, as it involves the movement of seeds away from the parental plants to particular habitats where they can germinate and transition to seedlings and ultimately adult plants. Seed dispersal is shaped by a diversity of abiotic and biotic factors, particularly by associations between plants and climate and between plants and other species. Due to the ongoing loss of biodiversity and changing global conditions, such interactions are prone to change and pose a severe threat to plant regeneration. One way to address this challenge is to study associations between plant traits and abiotic and biotic factors to understand the potential impacts of global change on plant regeneration. Plant communities have long been analyzed through the lens of vegetative traits, mainly ignoring how other traits interact and respond to the environment. For instance, while associations between vegetative traits (e.g., specific leaf area, leaf nitrogen content) and climate are well studied, there are few case studies of reproductive traits in relation to trait-environment associations in the context of global change.
Thus, the overarching aim of this dissertation is to explore how trait-environment associations, with a special focus on reproductive traits, can improve our understanding of the effect that global change may have on seed dispersal, and ultimately on plant regeneration. To this end, my research focuses on studying associations between plant traits and abiotic and biotic factors along an elevational gradient in both forests and deforested areas of tropical mountains. This dissertation addresses three principal research objectives.
First, I investigate the extent to which reproductive (seed and fruit traits) and vegetative traits (leaf traits) are related to abiotic and biotic factors for communities of fleshy-fruited plants in the Ecuadorian Andes. I used multivariate analyses to test associations between four (a)biotic factors and seven reproductive traits and five vegetative traits measured on 18 and 33 fleshy fruited plant species respectively. My analyses demonstrate that climate and soil conditions are strongly associated with the distribution of both reproductive and vegetative traits in tropical tree communities. The production of “costly” vs. “cheap” seeds, fruits and leaves, i.e., the production of few rewarding fruits and acquisitive leaves versus the production of many less-rewarding fruits and conservative leaves, is primarily limited by temperature, whereas the size of plant organs is more related to variation in precipitation and soil conditions. My findings suggest that associations between reproductive and vegetative traits and the abiotic environment follow similar principles in tropical tree communities.
Second, I assess how climate and microhabitat conditions affect the prevalence of endozoochorous plant species in the seed rain of tropical montane forests in southern Ecuador. I analyzed seed rain data for an entire year from 162 traps located across an elevational gradient spanning of 2000 m. I documented the microhabitat conditions (leaf area index and soil moisture next to each seed trap) at small spatial scale as well as the climatic conditions (mean annual temperature and rainfall in each plot) at large spatial scale. After a one-year of sampling, I counted 331,838 seeds of 323 species/morphospecies. My analyses demonstrate that the prevalence of endozoochorous plant species in the seed rain increases with temperature across elevations and with leaf area index within elevations. These results show that the prevalence of endozoochory is shaped by the interplay of both abiotic and biotic factors at large and small spatial scales.
Third, I examine the potential of seed rain to restore deforested tropical areas along an elevational gradient in southern Ecuador. For this chapter, I collected seed rain using 324 seed traps installed in 18 1-ha plots in forests (nine forest plots) and in pastures (nine deforested plots) along an elevational gradient of 2000 m. After a sampling period of three months, I collected a total of 123,039 seeds of 255 species/morphospecies from both forests and pastures along the elevational gradient. I did not find a consistent decrease in the amount and richness of seed rain between forests and pastures, but I detected a systematic change in the type of dispersed seeds, as heavier seeds and a higher proportion of endozoochorous species were found in forests compared to pastures at all elevations. This finding suggests that deforestation acts as a strong filter selecting seed traits that are vital for plant regeneration.
Understanding the role that trait-environment associations play in how plant communities regenerate today could serve as a basis for predicting changes in regeneration processes of plant communities under changing global conditions in the near future. Here, I show how informative the measurement of reproductive traits and trait environment associations are in facilitating the conservation of forest habitats and the restoration of deforested areas in the context of global change.
Climate risk has become a major concern for financial institutions and financial markets. Yet, climate policy is still in its infancy and contributes to increased uncertainty. For example, the lack of a sufficiently high carbon price and the variety of definitions for green activities lower the value of existing and new capital, and complicate risk management. This column argues that it would be welfare-enhancing if policy changes were to follow a predictable longer-term path. Accordingly, the authors suggest a role for financial regulation in the transition.
Climate crimes – a critique
(2023)
This paper aims on taking a critical approach to the emerging debate on climate criminal justice, that is mostly about something labeled „climate criminal law“ („Klimastrafrecht“). The critique is directed at climate crimes intended to protect our habitable climate („Klimaschutzstrafrecht“) or to prevent climate change („Klimawandelpräventionsstrafrecht“) staged as transformational criminal law. “Fighting" climate change with climate crimes can lull us into deceptive certainties and by extension into perilous idleness; and it will do so if we think of climate protection essentially in terms of traditional criminal law. Climate crimes are based on the idea that we can counter climate change with the "sharpest sword" available to a polity (cf. the German and Continental European ultima-ratio principle) and that we can thereby also get hold of "the powerful". But these certainties rest on but normative (and at heart: liberal) doctrines, which are deceptive in having lost touch with the realities of the administration of criminal justice. They obscure that more effective measures are available to mitigate the climate crisis and that "the powerful" will likely be shielded with and by climate crimes. Therefore, the climate crimes approach to the climate crisis may just turn out to be (self-)appeasement. It obfuscates that more effective measures are likely necessary to avert impending crises. Our critique is therefore not "only" directed at the symbolic, but the dysfunctional and "dark side" of climate crimes.
To understand the rapid rate of change in global biodiversity, it is necessary to analyse the present condition of ecosystems and to elucidate relationships of species to their environment. The BIOKLIM Project (Biodiversity and Climate Change Project) is intended to close this gap in our knowledge of montane and high montane forests of Central European low mountain ranges, one of the most threatened mixed montane systems worldwide. The Bavarian Forest National Park is characterised by its altitude range of ca. 800 m and a strongly developed gradient of forest structure. Relicts of old growth forests (areas of former local nature reserves) and dead stands, mostly killed by bark beetles, are accompanied by widely varying levels of woody debris and light. The gradients comprise a wide range of abiotic and forest structure factors, making the study area well suited for a multidisciplinary investigation of biodiversity. Unconstrained ordination (CA) of six taxa (vascular plants, wood inhabiting fungi, birds, carabids, spiders and molluscs) indicate the altitudinal gradient to be the main driver for distribution patterns of species assemblages. Objectives, structure, study design and data sampling of the BIOKLIM Project are described in detail. We set up 293 sampling plots along four main straight transects following the altitudinal gradient. All abiotic and stand structure data regarded as relevant are available for each plot. Vascular plants, wood inhabiting fungi and birds were sampled or mapped on all 293 plots. For the other 22 investigated taxa we used subsamples pre-stratified according to the sampling methods. The necessity of dealing with spatial autocorrelation, arising from sampling along linear transects, is described. Finally, study approach of our biodiversity project is compared with others involving altitudinal gradients. Worldwide, only a few multidisciplinary biodiversity studies have been previously conducted on long altitudinal gradients. However, in most cases sampling techniques were similar to ours, which allows comparison of results between continents. Keywords: Climate Change, Biodiversity, species-environment relationships
As a cognitively-mediated response, autonomous adaptation at farm-gate levels constitutes reactionary actions by farmers against climate impacts. These actions are shaped by interacting factors such as household characteristics, livelihood scope and resources. It is driven by the goal of adapting cultivated farmlands to climate and for sustaining crop yields. Thus, interest in balancing adaptation goals with protection of vegetation conditions is less of a priority. Lack of research interest in understanding the gap between objectives of reactionary adaptation and protection of surface conditions (vegetation canopies) is a gap in research. In many studies, farm-gate level adaptation is described as a set of zero-feedback actions in response to climate impacts. This perception conceals the stress and impact-engendering attribute of reactionary adaptation. Inspired towards addressing this conceptual gap; this study investigates impact of farmers’ reactionary adaptation on vegetation cover in Keffi, Nasarawa, Nigeria. A twenty-year time-series NDVI and rainfall datasets are linearly regressed to examine the extent of NDVI-rainfall sensitivity. A weak linear relationship between NDVI and rainfall in Keffi for the period, 1999-2018 is observed. At a regression slope of 0.001, R squared, R2=0.129 (implying that only about 13% of the variability in NDVI in Keffi are explained by rainfall amount) and a bivariate regression coefficient, r=0.359; statistical evidence shows that rainfall amount are not significant predictors of NDVI in Keffi. In investigating the possible interference of non-rainfall factors on vegetation productivity (NDVI) in Keffi; a residual trend (RESTREND) analysis was carried out. Regression of residuals from NDVI-Rainfall linear regression produced a R=0.192 with a negative and downwards slope. The downward character of the RESTREND slope is suggestive of non-rainfall factors contained in the residuals. In validating the RESTREND analysis, a comparative analysis between observed and predicted NDVI derived from a reference NDVI value of 0.46 was carried out. The NDVI value of 0.46, is empirically assumed to be average NDVI value expected at a minimum rainfall amount of 850mm/year reported in tropical Savanna ecosystems. Using this empirical relationship, NDVI values were predicted for Keffi. Even at higher rainfall amounts≈1340mm/year, amounts were unable to produce corresponding higher NDVI values; rather a more plausible correlation between reference-derived predicted NDVI values and rainfall was obtained. A further analysis with predicted NDVI values, based on 1999 NDVI value in Keffi returned higher NDVI units than observed NDVI values. This strengthens the attribution of the possible interference of rainfall-NDVI sensitivity by non-rainfall factors like human activities on vegetation productivity. Surface soil analysis to exclude potential impacts of soil nutrients and moisture deficiency on vegetation productivity, showed that soil had insignificant effect on vegetation dynamics. Further inferential analysis, using the inter-annual NDVI and the reclassified bi-decadal NDVI maps showed that spatial vegetation distribution in Keffi were driven by farmers inter-annual rotational cultivation footprints than rainfall variability. With a three-class categorization, “gain, loss and significant loss”, the spatial distribution of vegetation in Keffi between (1999-2008) and (2009-2018) was assessed. Temporal condition (stressed and healthy) across the three classes supports the attribution of farmers’ reactionary adaptation and cultivation practices on the dynamic spatial vegetation distribution. Between 1999 -2018, an increase in areas with significant vegetation loss (42%), so with a decrease of -25% in areas with healthy vegetation was observed. The character of vegetation cover across the two decadal time slices, reflects landuse intensity and unsustainable farming practices. Preferences for modification of cultivation practices and changes in seed by farmers exerts positive feedbacks on vegetation cover. Higher statistical measures, 38.4% (yearly cropping) and 44% (shifting cultivation with less fallow periods) were observed in the chi-square analysis. These measures were higher than 2.0% relating to shifting cultivation with more fallow periods. While 11.6% farmers noted cultural practices as reasons for preferred cultivation methods, 48.4% farmers attributed climate as reason behind cultivation modification. This was higher than 24.4% who linked issues of tenure rights to cultivation practices. With preferences for yield- breaching strategies, the non-receding cultivation and shorter fallow practices in Keffi triggers feedback on vegetation dynamics. Evidence from this study shows that the NDVI-rainfall functional sensitivity in Keffi is plausibly dampened by effects of reactionary farm-gate level adaptation practices.