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Featured Application: This study provides a general methodology for the assessment of the impact of climate change on reliability of structures, combining observations and climate projections, to the aim of giving guidance for the adaptation of climatic load maps in structural Codes. Climatic loads on structures are commonly defined under the assumption of stationary climate conditions; but, as confirmed by recent studies, they can significantly vary because of climate change effects, with relevant impacts not only for the design of new structures but also for the assessment of the existing ones. In this paper, a general methodology to evaluate the influence of climate change on climatic actions is presented, based on the analysis of observed data series and climate projections. Illustrative results in terms of changes in characteristic values of temperature, precipitation, snow, and wind loads are discussed for Italy and Germany, with reference to different climate models and radiative forcing scenarios. In this way, guidance for potential amendments in the current definition of climatic actions in structural codes is provided. Finally, the influence of climate change on the long-term structural reliability is estimated for a specific case study, showing the potential of the proposed methodology. [ABSTRACT FROM AUTHOR]

The climate change factor (CCF) is a precautionary instrument for technical flood protection that was introduced in Southern Germany in the early 2000s. The CCF was designed as a surcharge value to be added to all new technical flood protection facilities, such as dams, protection walls, and retention areas. This paper deconstructs the conditions and processes that led to the creation of this new policy instrument. Following the instrument choice framework, the paper analyzes in a heuristic manner, the institutions, actors, discourses, and decision context that were part of this process from the early 1990s to 2004, when the instrument was introduced. In order to better understand the scope of this regional instrument, the paper also briefly depicts four non-representative cases of flood risk and protection management, where the instrument was either applied or avoided. The article closes with an assessment of the CCF, concluding that the innovativeness of this instrument faded once the overarching sectoral paradigm shifted from technical flood protection to more comprehensive flood risk management. [ABSTRACT FROM AUTHOR]

Floods in Germany have become increasingly frequent and severe over recent decades, with notable events in 2002, 2013, and 2021. This study examines the trends and drivers of flood occurrences in Germany from 1990 to 2024, focusing on the influence of climate-change-related variables, such as temperature, precipitation, and river discharge. Using a comprehensive time series analysis, including Auto-Regressive Integrated Moving Average (ARIMA) and Artificial Neural Network (ANN) models and correlation and regression analyses, we identify significant correlations between these climatic variables and flood events. Our findings indicate that rising temperatures (with a mean of 8.46 °C and a maximum of 9 °C) and increased precipitation (averaging 862.26 mm annually)are strongly associated with higher river discharge (mean 214.6 m3/s) and more frequent floods (mean 197.94 events per year). The ANN model outperformed the ARIMA model in flood forecasting, showing lower error metrics (e.g., RMSE of 10.86 vs. 18.83). The analysis underscores the critical impact of climate change on flood risks, highlighting the necessity of adaptive flood-management strategies that incorporate the latest climatic and socio-economic data. This research contributes to the understanding of flood dynamics in Germany and provides valuable insights into future flood risks. Combining flood management with groundwater recharge could effectively lower flood risks and enhance water resources' mitigation and management. [ABSTRACT FROM AUTHOR]

The last ten years have witnessed an increase in publications focusing on bioeconomy as a proposal to confront the global challenges of climate change, depletion of non-renewable resources and ecosystem degradation. This paper investigates the scientific literature on issues related agricultural bioeconomy by applying a bibliometric network analysis. Bibliometric analysis is applied to the publications of the Scopus database during the period 2010–2020 in order to provide an overview of the main aspects that characterize agricultural bioeconomy. The results showed that out of a total of 1100 scientific papers, only 2.45% were published in 2010, while the corresponding share in 2020 was 20.81%. In the five years of 2016–2020, cumulatively, 70.63% of the publications were made, showing the dynamic evolution of bioeconomy. In addition, out of 85 countries in total, Germany and Italy are the two countries with most publications, while the fragmentation of research is evident with the creation of two main nodes, the European and the American. Moreover, keyword analysis showed that biomass and sustainability are two main recurring concepts, confirming that, currently, bioeconomy operates at three different levels: energy demand, land demand, and governance. It is apparent that to boost the development of agricultural bioeconomy, the following aspects should be assessed: the effective use of resources, an understanding of the key drivers of agricultural bioeconomy, and a clear perception of their associations. There is still no consensus as to which are the key factors that will accelerate its sustainable development. Our pursuit is to use the tools of bibliometric analysis to reach more critical conclusions regarding the agricultural bioeconomy, rather than approach it in a static way. [ABSTRACT FROM AUTHOR]

The hot summer of 2018 posed many challenges with regard to water shortages and yield losses, especially for agricultural production. These agricultural impacts might further pose consequent threats for the environment. In this paper, we deduce the impact of droughts on agricultural land management and on water quality owing to nitrate pollution. Using national statistics, we calculate a Germany-wide soil surface nitrogen budget for 2018 and deduce the additional N surplus owing to the dry weather conditions. Using a model farm approach, we compare fertilization practices and legal restrictions for arable and pig breeding farms. The results show that, nationwide, at least 464 kt of nitrogen were not transferred to plant biomass in 2018, which equals an additional average nitrogen surplus of 30 kg/ha. The surplus would even have amounted to 43 kg/ha, if farmers had continued their fertilization practice from preceding years, but German farmers applied 161 kt less nitrogen in 2018 than in the year before, presumably as a result of the new implications of the Nitrates Directive, and, especially on grassland, owing to the drought. As nitrogen surplus is regarded as an "agri-drinking water indicator" (ADWI), an increase of the surplus entails water pollution with nitrates. The examples of the model farms show that fertilization regimes with high shares of organic fertilizers produce higher nitrogen surpluses. Owing to the elevated concentrations on residual nitrogen in soils, the fertilization needs of crops in spring 2019 were less pronounced than in preceding years. Thus, the quantity of the continuously produced manure in livestock farms puts additional pressure on existing storage capacities. This may particularly be the case in the hot-spot regions of animal breeding in the north-west of Germany, where manure production, biogas plants, and manure imports are accumulating. The paper concludes that water shortages under climate change not only impact agricultural production and yields, but also place further challenges and threats to nutrient management and the environment. The paper discusses preventive and emergency management options for agriculture to support farmers in extremely dry and hot conditions. [ABSTRACT FROM AUTHOR]

Floods are among the most devastating and financially burdensome natural disasters in Europe. The combined impact of climate change and land use change is expected to exacerbate and intensify the destructive consequences of river floods. In this study, we analysed the effects of wetland restoration on peak and base flows and on water quality in the Kylldal catchment of the Kyll River in the German Middle Mountains using the Soil and Water Assessment Tool+ (SWAT+). Monthly median daily discharge increases varied between 3% and 33% in the studied (micro)catchments. The higher median flow rates show that discharge peaks were attenuated and distributed over a longer period, making both extreme peak flows and low flows less common. Peak flows tended to decrease, with the largest effects between late fall and early spring when peak flow values decreased by up to 18%. The annual maximum peak flows in each of the three micro-catchments decreased by 12–24% on average. The occurrence of daily average flow rates larger than 1 m3 s−1 was up to 45% lower after wetland restoration. Low flows increased by up to 21% and 13% in the summer and fall, respectively, which suggests that drought risk also decreases after wetland restoration. Average nitrogen exports decreased by 38–50% in the project areas and by 20% at the catchment level. Average phosphorus exports decreased by 52–67% in the project areas and by 25% at the catchment level. The study highlights the potential of wetland restoration for improving hydrological services, mitigating flood risks, and enhancing water quality. Restoring and maintaining freshwater ecosystems and their natural sponge functions is crucial for effectively managing water resources and addressing the challenges posed by climate change and land use changes. [ABSTRACT FROM AUTHOR]

Hydrogen is fast becoming a new international "super fuel" to accelerate global climate change ambitions. This paper has two inter-weaving themes. Contextually, it focuses on the potential impact of the EU's new Carbon Border Adjustment Mechanism (CBAM) on fossil fuel-generated as opposed to green hydrogen imports. The CBAM, as a transnational carbon adjustment mechanism, has the potential to impact international trade in energy. It seeks both a level playing field between imports and EU internal markets (subject to ambitious EU climate change policies), and to encourage emissions reduction laggards through its "carbon diplomacy". Countries without a price on carbon will be charged for embodied carbon in their supply chains when they export to the EU. Empirically, we focus on two hydrogen export/import case studies: Australia as a non-EU state with ambitions to export hydrogen, and Germany as an EU Member State reliant on energy imports. Energy security is central to energy trade debates but needs to be conceptualized beyond supply and demand economics to include geopolitics, just transitions and the impacts of border carbon taxes and EU carbon diplomacy. Accordingly, we apply and further develop a seven-dimension energy security-justice framework to the examples of brown, blue and green hydrogen export/import hydrogen operations, with varying carbon-intensity supply chains, in Australia and Germany. Applying the framework, we identify potential impact—risks and opportunities—associated with identified brown, blue and green hydrogen export/import projects in the two countries. This research contributes to the emerging fields of international hydrogen trade, supply chains, and international carbon diplomacy and develops a potentially useful seven-dimension energy security-justice framework for energy researchers and policy analysts. [ABSTRACT FROM AUTHOR]

In 2021, heavy precipitation events in Germany have confirmed once again that pluvial flooding can cause catastrophic damage in large, medium, and small cities. However, despite several hazard-oriented strategies already in place, to date there is still a lack of integrated approaches to actually preventing negative consequences induced by heavy rainfall events. Furthermore, municipalities across the world are still learning from recent episodes and there is a general need to explore new techniques and guidelines that could help to reduce vulnerability, and enhance the resilience, adaptive capacity, and sustainability of urban environments, considering the already predicted future challenges associated with climate variability. To address this gap, this paper presents the outcomes of the research project "Heavy Rainfall Checklist for Sewer Operation" which was conducted by IKT Institute for Underground Infrastructure, to involve all the stakeholders affected by pluvial flooding within cities, and implement a series of documents that can be adopted by municipalities across the world to support organizations and their operational staff in preventing problems caused by heavy rainfall incidents. More in detail, three different rainfall scenarios have been deeply analysed, and for each of them a list of specific tasks and suggestions has been provided for aiding decision-making. [ABSTRACT FROM AUTHOR]

This work seeks to answer the question as to whether the legal orders of Poland and Germany provide an effective framework for energy-efficient and climate-resilient urban space management. To this end, it verifies what similarities and differences exist between certain areas and whether they need reform. The starting point is the belief that legal instruments for environmentally friendly space management are a cross-border issue. Comparative studies are important because effective environmental protection knows no borders, and a lower level of protection in one country or geographic region can affect neighbouring countries and regions. The analysis of legal norms affecting such issues as passive energy construction; prevention of soil sealing and adequate ventilation; reduction of CO2 emissions; promotion of green areas; proper water management; reduction of so-called "grey energy" associated with new construction; the compact city; and a reduction of light pollution has enabled us to synthesise findings into specific conclusions and to propose postulates and directions for further research. However, this does not change the overall assessment that the legal systems of Poland and Germany enable environmentally friendly space management at a similar level, while at the same time, certain additions to the regulations and a further discussion of possible improvements are most welcome and needed. [ABSTRACT FROM AUTHOR]

Germany's increasing temperatures and droughts are significantly impacting the hydrological realm. This study examines the implications of climate change on future droughts in a representative catchment within Germany's low mountain range. Findings of this research shed light on potential impacts on future seasonal water availability, aiding decision makers and stakeholders in managing regional climate change risks. Climate and drought indices, as well as the climatic water balance, are computed and analyzed until 2100, relative to a reference period. A high emission scenario (RCP8.5) and a climate protection scenario (RCP2.6) are considered to address uncertainties. Results reveal above-average warming in the study area compared to the national average. Under the RCP8.5 scenario, the far future exhibits an average of 44 annual heat days. Despite wetter winters, extended droughts persist. Water stress intensifies in summer and autumn, with a projected 68% increase in dry period duration. The findings emphasize the necessity of adaptation strategies, as even ambitious global warming mitigation efforts require regional adaptation. The study represents the first application of a Germany-wide, bias-adjusted, and regionalized dataset at catchment level. It contributes novel insights for regional water resources management and advances understanding of climate change impacts in German low mountain range regions. [ABSTRACT FROM AUTHOR]

Earth's forests are increasingly exposed to climate risks through climate change-related drought and heat waves. Here, we review the climate vulnerability of European beech (Fagus sylvatica), the most abundant tree species of Central Europe's temperate forests, and its adaptation potential to a hotter and drier climate in northern Germany, close to the center of the species' distribution range. About two-thirds of the studied beech forests show persistent negative growth trends of their dominant trees since the onset of rapid warming in the early 1980s, driven primarily by long-term deterioration of the climatic water balance (CWB) in summer and, locally, long-term decrease in June precipitation. Lower water storage capacity of the soil increases the climate sensitivity of growth. Even though beech populations of drier sub-regions reveal some acclimation to drought (reduced stomatal conductance, turgor loss point reduction, higher C allocation to roots), they are more climate-vulnerable than populations at moister sites, visible in larger growth decreases and greater CWB sensitivity of growth. Even though beech mortality is still lower in the study region than in other parts of Central Europe, our results identify beech forest regions with <350 mm growing-season precipitation as vulnerable to recent climate conditions, which refers to half of the study region. With further climate warming and aridification, most of northern Germany likely will become unfavorable for beech growth within the next tree generation, which suggests choosing in many production forests alternative, more drought- and heat-resistant timber species. [ABSTRACT FROM AUTHOR]

Climate changes necessitate measures to reduce greenhouse gas emissions (GHG). The European Union's climate and energy policy places particular emphasis on the development of renewable energy, considered to be the primary mean in achieving the climate neutrality goal by 2050. Having in mind the aforementioned, the study was conducted to determine time delay in the development of renewable energy sources between the Visegrad Group (V4) countries and Germany, considered the most advanced country in developing renewable energy and having the greatest impact on shaping European Union climate and energy policy. The time delay econometric method was used in four of its variants. The research results show that, despite the existence of support mechanisms, the development of renewable energy sources (RES) in the V4 countries has a high mutual correlation. There is a hight correlation between RES penetration in energy mix and UE goals of the climate and energy policy until 2020. At the same time, the available data from the analysed period 2004–2019 indicate growing time delay between the reference facility—Germany and the surveyed group. The paper identifies the primary factors behind the identified time delay and proposes research areas that could direct the future research of those aspects. [ABSTRACT FROM AUTHOR]

With the rapid expansion of cities due to population growth and urbanization, conventional centralized wastewater collection and treatment systems are slowly becoming a burden; expensive maintenance is required for aging plants and piping infrastructure, the cost of expanding the capacity to cover demand from population growth, and new regulations for tighter control over certain pollutants such as micropollutants. As an alternative to this system, this study discusses the feasibility of decentralized treatment systems at the neighborhood scale. Taking a Water-Energy-Food (WEF) Nexus approach, such systems can support water and energy conservation, recovery of water, energy, and nutrients as well as generation of energy from wastewater, be customized to individual water and energy requirements, and eliminate the need for lengthy pipe networks. The method employed in this study is comparing the economic feasibility of the status quo to a proposed decentralized solution. The study finds that the costs of implementing a hypothetical decentralized water reclamation with an integrated resource recovery system using an anaerobic membrane bioreactor (AnMBR) in a downtown high-density neighborhood of the city of Munich, Germany, can theoretically be recuperated within two years. This alternative system may cost 60% of what it costs to run the centralized system. By linking the AnMBR to a biogas digestor and using systematically harvested organic waste as a co-substrate, the decentralized system can generate enough energy to run itself and even feed some energy to the grid. This study is highly hypothetical, yet generating evidence such as this can support a systemic socio-technical transition towards a more circular economy with optimal resource recovery. [ABSTRACT FROM AUTHOR]

A possible adaptation pathway for water suppliers in Germany who face a climatically driven increase in water stress is the development of aquifers which are not used at their full potential. However, identifying suitable sites for aquifer development can go along with severe conflict potential due to the great variety of stakeholders who are involved in the decision-making process. We approach this multi-actor and multi-criteria decision-making problem by developing a geoinformation system-based analytic hierarchy process ensemble (GIS-AHP ensemble). As opposed to the classic GIS-AHP method that yields ratings of site suitability based on a single expert evaluation, the here proposed new GIS-AHP ensemble method respects multiple expert evaluations and allows for quantifying the robustness of yielded site ratings in multi-actor contexts, which helps to mitigate conflict potential. The respectively derived GIS-AHP ensemble site ratings for northwest Germany are successfully checked for plausibility in the framework of the study by using long-established groundwater abstraction areas as indicators for good site conditions. The GIS-AHP ensemble site ratings are further tested regarding their usability for long-term water supply planning by integrating a groundwater recharge scenario under climate change for the period 2020 to 2050. The proposed GIS-AHP ensemble methodology proves useful in the given case study for fostering integrated environmental decision-making and exhibits a high transferability to other, thematically differing site selection problems. [ABSTRACT FROM AUTHOR]

This study aims to advance our knowledge in the genesis of extreme climatic events with the dual aim of improving forecasting methods while clarifying the role played by anthropogenic warming. Wavelet analysis is used to highlight the role of coherent Sea Surface Temperature (SST) anomalies produced from short-period oceanic Rossby waves resonantly forced, with two case studies: a Marine Heatwave (MHW) that occurred in the northwestern Pacific with a strong climatic impact in Japan, and an extreme flood event that occurred in Germany. Ocean–atmosphere interactions are evidenced by decomposing state variables into period bands within the cross-wavelet power spectra, namely SST, Sea Surface Height (SSH), and the zonal and meridional modulated geostrophic currents as well as precipitation height, i.e., the thickness of the layer of water produced during a day, with regard to subtropical cyclones. The bands are chosen according to the different harmonic modes of the oceanic Rossby waves. In each period band, the joint analysis of the amplitude and the phase of the state variables allow the estimation of the regionalized intensity of anomalies versus their time lag in relation to the date of occurrence of the extreme event. Regarding MHWs in the northwestern Pacific, it is shown how a warm SST anomaly associated with the northward component of the wind resulting from the low-pression system induces an SST response to latent and sensible heat transfer where the latitudinal SST gradient is steep. The SST anomaly is then shifted to the north as the phase becomes homogenized. As for subtropical cyclones, extreme events are the culmination of exceptional circumstances, some of which are foreseeable due to their relatively long maturation time. This is particularly the case of ocean–atmosphere interactions leading to the homogenization of the phase of SST anomalies that can potentially contribute to the supply of low-pressure systems. The same goes for the coalescence of distinct low-pressure systems during cyclogenesis. Some avenues are developed with the aim of better understanding how anthropogenic warming can modify certain key mechanisms in the evolution of those dynamic systems leading to extreme events. [ABSTRACT FROM AUTHOR]

Climate change is producing threats to forests' capacity of regulating water regimes. Therefore, thinning strategies can be applied to mitigate climate change impacts more efficiently by providing more spaces for trees to utilize resources e.g., water and nutrients. This study examined the effects of different thinning intensities and intervals on water characteristics and biomass growth of a 75-year-old Norway spruce (Picea abies) stand in the Black Forest, Germany. Here we used a water and management sensitive update of the process-based forest growth model 3PG, 3PG-Hydro. We applied light (10%), moderate (30%), and heavy thinning (50% intensity) in the interval of 10, 25, and 50 years of the management period. We simulated growth with climate change scenario RCP 8.5 data from 1995 to 2065. We analyzed the effects of the different thinning regimens on biomass, evapotranspiration as well as water yield. Thinning intensity and interval as well as their interaction have significant influence on production of stand biomass and water yield for all thinning regimes applied (p < 0.05). However, there is no significant difference (p > 0.05) in accumulated biomass (thinned biomass added to the stand biomass) between the applied thinning regimes. Light thinning in a long interval (50 years) produced highest stand biomass among the applied thinning regimes. Furthermore, the prediction showed that accumulated water yield increased with increasing thinning intensity. Our study concludes that repeated moderate thinning at intermediate intervals results in a high water yield without losing biomass production. [ABSTRACT FROM AUTHOR]

The training system Semi-Minimal-Pruned Hedge (SMPH) blends features of traditional Vertical Shoot Positioning-type (VSP) trellising systems with the concept of minimal pruning. While saving labor, this training system results in relatively high crop load and a poor leaf area to fruit weight-ratio (LFR), and thus, needs to be able to ripen grapes in a cool to moderate climate. For these reasons the impact of yield regulation strategies, including (i) shoot thinning (Darwin-Rotor), (ii) biotechnological thinning (Gibberellic acid), and (iii) bunch thinning (harvest machine) were trialed in a three year study at Geisenheim, Germany between 2017 and 2019 using Riesling (Vitis vinifera L.). The average yield per vine in SMPH (5.34 ± 1.10 kg) was 61.1% higher with a narrower LFR (14.01 cm2 g−1), compared with VSP (3.32 ± 1.02 kg, LFR: 16.99 cm2 g−1). The yield was successfully reduced and LFR simultaneously increased with shoot thinning (−33.1%, LFR: 19.04 cm2 g−1), biotechnological thinning (−18.3%, LFR: 16.69 cm2 g−1) and bunch thinning (−37.3%, LFR: 21.49 cm2 g−1). Ripening was delayed in SMPH. On average, two maturity thresholds (14.1 °Brix and 18.2 °Brix) were achieved 129 GDD (seven days according to the recorded daily mean temperatures, respectively) and 269 GDD (16 days) later in non-thinned SMPH, compared to VSP. All thinning treatments accelerated maturity progress ranging from 27 GDD (two days) to 58 GDD (three days) for 14.1 °Brix and 59 GDD (three days) to 105 GDD (six days) for 18.2 °Brix. Apart from immediate benefits on the economic efficiency, the adaption of the leaf area to fruit weight ratio using SMPH holds high potential to, (i) produce grapes targeting specific wine profiles and/or (ii) reducing the velocity of ripening under conditions of climatic change. [ABSTRACT FROM AUTHOR]

To develop measures to reduce the vulnerability of forests to drought, it is necessary to estimate specific water balances in sites and to estimate their development with climate change scenarios. We quantified the water balance of seven forest monitoring sites in northeast Germany for the historical time period 1961–2019, and for climate change projections for the time period 2010–2100. We used the LWF-BROOK90 hydrological model forced with historical data, and bias-adjusted data from two models of the fifth phase of the Coupled Model Intercomparison Project (CMIP5) downscaled with regional climate models under the representative concentration pathways (RCPs) 2.6 and 8.5. Site-specific monitoring data were used to give a realistic model input and to calibrate and validate the model. The results revealed significant trends (evapotranspiration, dry days (actual/potential transpiration < 0.7)) toward drier conditions within the historical time period and demonstrate the extreme conditions of 2018 and 2019. Under RCP8.5, both models simulate an increase in evapotranspiration and dry days. The response of precipitation to climate change is ambiguous, with increasing precipitation with one model. Under RCP2.6, both models do not reveal an increase in drought in 2071–2100 compared to 1990–2019. The current temperature increase fits RCP8.5 simulations, suggesting that this scenario is more realistic than RCP2.6. [ABSTRACT FROM AUTHOR]

Lakes are known to be strongly affected by climate change as a result of their sensitivity to atmospheric forcing. The combined response of urban lakes to climatic changes and to urbanization of the catchment may be further altered by water quality management measures. We studied Lake Tegel in Berlin, Germany as a representative urban lake profoundly influenced by intense water management measures and a resulting complex hydrodynamic situation: Lake Tegel is fed by nutrient-rich river discharges and effluents from a phosphorus elimination plant (PEP). We estimated changes in water temperatures, the Wedderburn number, and the buoyancy frequency, as well as concentrations of dissolved oxygen and phosphate under climate change using a one-dimensional vertical hydrodynamic model coupled to a water quality model. Further, we investigated how four management scenarios with varying discharges of the PEP could affect the lake system. In all simulations, water temperatures increased and summer stratification extended. The modeling results demonstrated that the water management system buffers the high nutrient supply from the river inflow and can effectively mitigate negative effects of climate change on Lake Tegel, thus highlighting its importance for the lake ecosystem. [ABSTRACT FROM AUTHOR]

Climate signal maps can be used to identify regions where robust climate changes can be derived from an ensemble of climate change simulations. Here, robustness is defined as a combination of model agreement and the significance of the individual model projections. Climate signal maps do not show all information available from the model ensemble, but give a condensed view in order to be useful for non-climate scientists who have to assess climate change impact during the course of their work. Three different ensembles of regional climate projections have been analyzed regarding changes of seasonal mean and extreme precipitation (defined as the number of days exceeding the 95th percentile threshold of daily precipitation) for Germany, using climate signal maps. Although the models used and the scenario assumptions differ for the three ensembles (representative concentration pathway (RCP) 4.5 vs. RCP8.5 vs. A1B), some similarities in the projections of future seasonal and extreme precipitation can be seen. For the winter season, both mean and extreme precipitation are projected to increase. The strength, robustness and regional pattern of this increase, however, depends on the ensemble. For summer, a robust decrease of mean precipitation can be detected only for small regions in southwestern Germany and only from two of the three ensembles, whereas none of them projects a robust increase of summer extreme precipitation. [ABSTRACT FROM AUTHOR]

It is crucial to define and quantify possible impacts of climate change on wildlife in order to be able to pre-adapt management strategies for nature conservation. Thus, it is necessary to assess which species might be affected by climatic changes, especially at the regional scale. We present a novel approach to estimate possible climate change induced turnovers in bird communities and apply this method to Lüneburg Heath, a region in northern Germany. By comparing species pools of future climatically analogous regions situated in France with the Lüneburg Heath species pool, we detected possible trends for alterations within the regional bird community in the course of climate change. These analyses showed that the majority of bird species in Lüneburg Heath will probably be able to tolerate the projected future climate conditions, but that bird species richness, in general, may decline. Species that might leave the community were often significantly associated with inland wetland habitats, but the proportion of inland wetlands within the regions had a significant influence on the magnitude of this effect. Our results suggest that conservation efforts in wetlands have to be strengthened in light of climate change because many species are, in principle, able to tolerate future climate conditions if sufficient habitat is available. [ABSTRACT FROM AUTHOR]

As a result of global climate change, heavy rainfall events and dry periods are increasingly occurring in Germany, with consequences for the water and solute balance of soils to be expected. The effects of climate change on nitrogen and carbon leaching were investigated using 21 non-weighable manually filled lysimeters of the UFZ lysimeter facility Falkenberg, which have been managed since 1991 according to the principles of the best management practices and organic farming. Based on a 29-year dataset (precipitation, evaporation, leachate, nitrate and dissolved organic carbon concentrations), the lysimeter years 1995/96, 2018/19, and 2003/04 were identified as extremely dry years. Under the climatic conditions in northeastern Germany, seepage fluxes were disrupted in these dry years. The reoccurrence of seepage was associated with exceptionally high nitrogen concentrations and leaching losses, which exceeded the current drinking water limits by many times and may result in a significant risk to water quality. In contrast, increased DOC leaching losses occurred primarily as a result of increased seepage fluxes. [ABSTRACT FROM AUTHOR]

In the Central German Uplands, Fagus sylvatica and Picea abies have been particularly affected by climate change. With the establishment of beech forests about 3000 years ago and pure spruce stands 500 years ago, they might be regarded as 'neophytes' in the Hessian forests. Palaeoecological investigations at wetland sites in the low mountain ranges and intramontane basins point to an asynchronous vegetation evolution in a comparatively small but heterogenous region. On the other hand, palynological data prove that sustainably managed woodlands with high proportions of Tilia have been persisting for several millennia, before the spread of beech took place as a result of a cooler and wetter climate and changes in land management. In view of increasingly warmer and drier conditions, Tilia cordata appears especially qualified to be an important silvicultural constituent of the future, not only due to its tolerance towards drought, but also its resistance to browsing, and the ability to reproduce vegetatively. Forest managers should be encouraged to actively promote the return to more stress-tolerant lime-dominated woodlands, similar to those that existed in the Subboreal chronozone. [ABSTRACT FROM AUTHOR]

Climate change imposes severe stress on European forests, with forest degradation already visible in several parts of Europe. Thus adaptation of forestry applications in Mediterranean areas and central Europe is necessary. Proactive forestry management may include the planting of Mediterranean oak species in oak-bearing Central European regions. Five replicate common gardens of Greek and Italian provenances of Quercus ilex, Q. pubescens and Q. frainetto seedlings (210 each per plantation) were established in Central Italy, NE Greece (two) and Southern Germany (two, including Q. robur) to assess their performance under different climate conditions. Climate and soil data of the plantation sites are given and seedling establishment was monitored for survival and morphological parameters. After 3 years (2019) survival rates were satisfactory in the German and Italian sites, whereas the Greek sites exerted extremely harsh conditions for the seedlings, including extreme frost and drought events. In Germany, seedlings suffered extreme heat and drought periods in 2018 and 2019 but responded well. Provenances were ranked for each country for their performance after plantation. In Greece and Italy, Q. pubescens was the best performing species. In Germany, Q. pubescens and Q. robur performed best. We suggest that Greek or Italian provenances of Q. pubescens may be effectively used for future forestation purposes in Central Europe. For the establishment of Quercus plantations in Northern Greece, irrigation appears to be a crucial factor in seedling establishment. [ABSTRACT FROM AUTHOR]

Research Highlights: Our results provide novel perspectives on the effectiveness and collapse of compensatory mechanisms of tracheid development of Norway spruce during intra-seasonal drought and the environmental control of intra-annual density fluctuations. Background and Objectives: This study aimed to compare and integrate complementary methods for investigating intra-annual wood formation dynamics to gain a better understanding of the endogenous and environmental control of tree-ring development and the impact of anticipated climatic changes on forest growth and productivity. Materials and Methods: We performed an integrated analysis of xylogenesis observations, quantitative wood anatomy, and point-dendrometer measurements of Norway spruce (Picea abies (L.) Karst.) trees growing along an elevational gradient in South-western Germany during a growing season with an anomalous dry June followed by an extraordinary humid July. Results: Strong endogenous control of tree-ring formation was suggested at the highest elevation where the decreasing rates of tracheid enlargement and wall thickening during drought were effectively compensated by increased cell differentiation duration. A shift to environmental control of tree-ring formation during drought was indicated at the lowest elevation, where we detected absence of compensatory mechanisms, eventually stimulating the formation of an intra-annual density fluctuation. Transient drought stress in June also led to bimodal patterns and decreasing daily rates of stem radial displacement, radial xylem growth, and woody biomass production. Comparing xylogenesis data with dendrometer measurements showed ambivalent results and it appears that, with decreasing daily rates of radial xylem growth, the signal-to-noise ratio in dendrometer time series between growth and fluctuations of tree water status becomes increasingly detrimental. Conclusions: Our study provides new perspectives into the complex interplay between rates and durations of tracheid development during dry-wet cycles, and, thereby, contributes to an improved and mechanistic understanding of the environmental control of wood formation processes, leading to the formation of intra-annual density fluctuations in tree-rings of Norway spruce. [ABSTRACT FROM AUTHOR]

The effects of climate change on agricultural ecosystems are increasing, and droughts affect many regions. Drought has substantial ecological, social, and economic consequences for the sustainability of agricultural land. Many regions of the northern hemisphere have not experienced a high frequency of meteorological droughts in the past. For understanding the implications of climate change on grassland, analysis of the long-term climate data provides key information relevant for improved grassland management strategies. Using weather data and grassland production data from a long-term permanent grassland site, our aims were (i) to detect the most important drought periods that affected the region and (ii) to assess whether climate changes and variability significantly affected forage production in the last decade. For this purpose, long-term daily weather data (1961–2019) and the standardized precipitation index (SPI), De Martonne index (IDM), water deficit (WD), dryness index (DI), yield anomaly index (YAI), and annual yield loss index (YL) were used to provide a scientific estimation. The results show that, despite a positive trend in DI and a negative trend in WD and precipitation, the time-series trends of precipitation, WD, and DI indices for 1961–2019 were not significant. Extreme dry conditions were also identified with SPI values less than −2. The measured annual forage yield (2007–2018) harvested in a four-cut silage system (with and without organic N-fertilization) showed a strong correlation with WD (R = 0.64; p ˂ 0. 05). The main yield losses were indicated for the years 2008 and 2018. The results of this study could provide a perspective for drought monitoring, as well as drought warning, in grassland in northwest Europe. [ABSTRACT FROM AUTHOR]

There are numerous studies assessing the influence of individual sociological, political, and demographic factors on attitudes towards climate change. However, there is still a need for a deeper understanding of the reasons behind these attitudes and for research based on results from more than one country. This study empirically examines a range of psychosocial and demographic determinants of support for climate policy (renewable energy, energy efficiency and carbon tax) in Germany and Poland (n = 1969). The results show that the societies of both countries, despite significant differences in income, culture and political stance on climate change, similarly support implementation of climate policies. For both countries valid predictors of support are: awareness, emotional response to climate crisis, sense of control, and belief in effectiveness of solutions; the study also shows predictors relevant in only one country. Factor analysis identified similar dimensions of attitudes toward climate change in both countries. The main findings show that support for climate policy is high in both countries and that the public is ready to accept more ambitious climate goals. Despite the differences between the countries, a coherent climate policy seems justified. The study also shows differences between the countries and provides recommendations for policymakers. [ABSTRACT FROM AUTHOR]

Climate modelling output that was provided under the latest Coupled Model Intercomparison Project (CMIP6) shows significant changes in model-specific Equilibrium Climate Sensitivity (ECS) as compared to CMIP5. The newer versions of many Global Climate Models (GCMs) report higher ECS values that result in stronger global warming than previously estimated. At the same time, the multi-GCM spread of ECS is significantly larger than under CMIP5. Here, we analyse how the differences between CMIP5 and CMIP6 affect climate projections for Germany. We use the statistical-empirical downscaling method EPISODES in order to downscale GCM data for the scenario pairs RCP4.5/SSP2-4.5 and RCP8.5/SSP5-8.5. We use data sets of the GCMs CanESM, EC-Earth, MPI-ESM, and NorESM. The results show that the GCM-specific changes in the ECS also have an impact at the regional scale. While the temperature signal under regional climate change remains comparable for both CMIP generations in the MPI-ESM chain, the temperature signal increases by up to 3 °C for the RCP8.5/SSP5-8.5 scenario pair in the EC-Earth chain. Changes in precipitation are less pronounced and they only show notable differences at the seasonal scale. The reported changes in the climate signal will have direct consequences for society. Climate change impacts previously projected for the high-emission RCP8.5 scenario might occur equally under the new SSP2-4.5 scenario. [ABSTRACT FROM AUTHOR]

Kettle holes are small water bodies of glacial origin which mostly occur in agricultural landscapes. They provide numerous ecosystem services (ES), but their supply may be negatively affected by agricultural management. We conducted a literature review to identify which ES are supplied by kettle holes and to analyze feedbacks with agricultural management. Taking Germany as a test case, we also analyzed how kettle holes are addressed in policy documents and for which ES they are regulated. This was done to identify the societal value officially associated with kettle holes. The literature review found eight ES attributed to kettle holes, of which hydrological cycle and flood control, chemical condition of freshwaters, nursery populations and habitats and biotic remediation of wastes were addressed most often. In contrast, only the provision of habitat service was addressed in German policy documents related to kettle holes. We identified types of agricultural management that negatively affected the supply of ES by kettle holes, in particular artificial drainage, high levels of pesticide and fertilizer application, and management where tillage and erosion result in elevated sediment inputs. Additionally, climate change may lead to an increased drying up of kettle holes. Based on our finding, we conclude that the intensity of agricultural management around kettle holes threatens the supply of all ES while only the service of providing habitats for biodiversity is addressed in German policy regulations. Further regulation is required to induce agricultural management change towards a conservation of all ES supplied by kettle holes. [ABSTRACT FROM AUTHOR]

This study investigates the different stakeholder based discourses and challenges around the Franconian Lake District (FLD), a recently constructed large reservoir system in Germany. The construction and operation of reservoirs represent a massive alteration of their natural and social environments leading to discourses and potential conflicts between a wide scope of heterogeneous interest patterns. Studies have shown that large reservoirs can be an important contributor to water supply, irrigation, energy storage and therefore climate change mitigation on a global scale, which brings these conflicting interests to a broader societal concern. Yet, information about conflicts around existing (German) reservoirs is limited. To assess which issues and conflicts appear on the daily agenda and how they are perceived, communicated and addressed by the stakeholders, a total of 609 articles in the Nürnberger Nachrichten and 22 semi-structured expert interviews were analysed, using qualitative content analysis. The results show that discourses at FLD are predominantly determined by economic factors. Management issues are dominated by discussions about cyanobacteria, which can pose a health risk, thereby impeding recreational use of the lakes and consequently causing economic losses and an image problem for the region. The issue is also strongly interlinked with other aspects of concern and therefore one of the main challenges at the FLD. Due to the construction of the lakes and the evolving strong tourism sector, the formerly agricultural region was subject to a major structural change linking together a very heterogeneous set of interests. The results of this study can help in establishing a management framework to suit all stakeholders and possibly be transferrable to similar projects. [ABSTRACT FROM AUTHOR]

A significant reduction in greenhouse gas emissions will be necessary in the coming decades to enable the global community to avoid the most dangerous consequences of man-made global warming. This fact is reflected in Germany's 7th Federal Energy Research Program (EFP), which was adopted in 2018. Direct Air Capture (DAC) technologies used to absorb carbon dioxide (CO2) from the atmosphere comprise one way to achieve these reductions in greenhouse gases. DAC has been identified as a technology (group) for which there are still major technology gaps. The intention of this article is to explore the potential role of DAC for the EFP by using a multi-dimensional analysis showing the technology's possible contributions to the German government's energy and climate policy goals and to German industry's global reputation in the field of modern energy technologies, as well as the possibilities of integrating DAC into the existing energy system. The results show that the future role of DAC is affected by a variety of uncertainty factors. The technology is still in an early stage of development and has yet to prove its large-scale technical feasibility, as well as its economic viability. The results of the multi-dimensional evaluation, as well as the need for further technological development, integrated assessment, and systems-level analyses, justify the inclusion of DAC technology in national energy research programs like the EFP. [ABSTRACT FROM AUTHOR]