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In Germany, emissions from drained organic soils contributed approximately 53.7 Mio. t of carbon dioxide equivalents (CO2-eq) to the total national greenhouse gas (GHG) emissions in 2021. In addition to restoration measures, shifting management practices, rewetting, or using peatlands for paludiculture is expected to significantly reduce GHG emissions. The effects of climate change on these mitigation measures remains to be tested. In a 2017 experimental field study on agriculturally used grassland on organic soil, we assessed the effects of rewetting and of predicted climate warming on intensive grassland and on extensively managed sedge grassland (transplanted Carex acutiformis monoliths). The testing conditions of the two grassland types included drained versus rewetted conditions (annual mean water table of − 0.13 m below soil surface), ambient versus warming conditions (annual mean air temperature increase of + 0.8 to 1.3 °C; use of open top chambers), and the combination of rewetting and warming. We measured net ecosystem exchange of CO2, methane and nitrous oxide using the closed dynamic and static chamber method. Here, we report the results on the initial year of GHG measurements after transplanting adult Carex soil monoliths, including the controlled increase in water level and temperature. We observed higher N2O emissions than anticipated in all treatments. This was especially unexpected for the rewetted intensive grasslands and the Carex treatments, but largely attributable to the onset of rewetting coinciding with freeze–thaw cycles. However, this does not affect the overall outcomes on mitigation and adaptation trends. We found that warmer conditions increased total GHG emissions of the drained intensive grassland system from 48.4 to 66.9 t CO2-eq ha−1 year−1. The shift in grassland management towards Carex paludiculture resulted in the largest GHG reduction, producing a net cooling effect with an uptake of 11.1 t CO2-eq ha−1 year−1. Surprisingly, we found that this strong sink could be maintained under the simulated warming conditions ensuing an emission reduction potential of − 80 t CO2-eq ha−1 year−1. We emphasize that the results reflect a single initial measurement year and do not imply the permanence of the observed GHG sink function over time. Our findings affirm that rewetted peatlands with adapted plant species could sustain GHG mitigation and potentially promote ecosystem resilience, even under climate warming. In a warmer world, adaptation measures for organic soils should therefore include a change in management towards paludiculture. Multi-year studies are needed to support the findings of our one-year experiment. In general, the timing of rewetting should be considered carefully in mitigation measures. [ABSTRACT FROM AUTHOR]

We shed new light on a long-standing question in political science: When confronted with costly policy choices, do citizens form their preferences using material (economic) concerns or other-regarding motivations, such as the distribution of costs, and how are these moderated by political ideology? Using the case of carbon taxation, a widely advocated policy solution to climate change, we conducted survey experiments in Germany and the United States to assess the relative importance of these forms of preferences. The results show that individuals are primarily concerned with how a carbon tax would affect their individual income. There are also important cross-national differences with high-income German respondents being more receptive to redistributive policy design, especially in contrast to high-income Democrats who significantly decrease support for carbon taxation. These findings highlight how the constituencies generated by new policies can significantly alter the distribution of mass support for action on emerging societal problems. [ABSTRACT FROM AUTHOR]

Mountain forests are plant diversity hotspots, but changing climate and increasing forest disturbances will likely lead to far‐reaching plant community change. Projecting future change, however, is challenging for forest understory plants, which respond to forest structure and composition as well as climate. Here, we jointly assessed the effects of both climate and forest change, including wind and bark beetle disturbances, using the process‐based simulation model iLand in a protected landscape in the northern Alps (Berchtesgaden National Park, Germany), asking: (1) How do understory plant communities respond to 21st‐century change in a topographically complex mountain landscape, representing a hotspot of plant species richness? (2) How important are climatic changes (i.e., direct climate effects) versus forest structure and composition changes (i.e., indirect climate effects and recovery from past land use) in driving understory responses at landscape scales? Stacked individual species distribution models fit with climate, forest, and soil predictors (248 species currently present in the landscape, derived from 150 field plots stratified by elevation and forest development, overall area under the receiving operator characteristic curve = 0.86) were driven with projected climate (RCP4.5 and RCP8.5) and modeled forest variables to predict plant community change. Nearly all species persisted in the landscape in 2050, but on average 8% of the species pool was lost by the end of the century. By 2100, landscape mean species richness and understory cover declined (−13% and −8%, respectively), warm‐adapted species increasingly dominated plant communities (i.e., thermophilization, +12%), and plot‐level turnover was high (62%). Subalpine forests experienced the greatest richness declines (−16%), most thermophilization (+17%), and highest turnover (67%), resulting in plant community homogenization across elevation zones. Climate rather than forest change was the dominant driver of understory responses. The magnitude of unabated 21st‐century change is likely to erode plant diversity in a species richness hotspot, calling for stronger conservation and climate mitigation efforts. [ABSTRACT FROM AUTHOR]

Germany is known as a leader in energy transition, but the country keeps falling short of meeting stated objectives. While attention has been high on climate change related policy leadership, the competing domestic alliances in the field of energy transition have received scant attention. In Germany, the strong momentum of the conversion to renewable energy has been stalled in the second half of the 2010s. Enabled by an increasing weight of neoliberal economic concerns, traditional energy coalitions have managed to reshape the path of energy transition. In this article three competing discourse coalitions are introduced to examine their constituencies and projects in the field of energy and politics. It focuses on radical ecological forces around the Öko-Institut, environmental modernization capacities linked to Green Budget Germany and fossil interest groups intersecting with neoliberal academic and partisan think tanks. As such, the article opens a view on multiple contestations over Germany's Energiewende. [ABSTRACT FROM AUTHOR]

To successfully battle climate change, it is crucial to reach people across political camps and national borders. Research from dual-party systems indicates that climate change communication is most effective when it addresses how climate action promotes recipients' political values. Yet, to our knowledge, there is no such evidence from multi-party systems. To fill this gap, we conducted three studies in two Central European, German-speaking countries: Germany and Austria. In Study 1, we framed conservative and liberal climate protection messages using values from Schwartz's Theory of Basic Human Values. Liberals agreed more with the liberally framed than with the conservatively framed climate protection message. In Study 2, we framed the climate protection message based on moral foundations. Conservative participants agreed more with the conservatively framed climate protection message than with the liberally framed one. Study 3 integrated values from multiple frameworks, and ultimately conservatives as well as liberals agreed more to climate protection statements that touched on values reflecting their political ideology. Thus, empirical findings from dual-party systems hold for countries with more than two parties. [ABSTRACT FROM AUTHOR]

Adverse consequences of climate change often affect people and places far away from those that have the greatest capacity for mitigation. Several correlational and some experimental studies suggest that the willingness to take mitigation actions may diminish with increasing distance. However, the empirical findings are ambiguous. In order to investigate if and how socio-spatial distance to climate change effects plays a role for the willingness to engage in mitigation actions, we conducted an online experiment with a German population sample (n = 383). We find that the willingness to sign a petition for climate protection was significantly reduced when a person in India with a name of Indian origin was affected by flooding, as compared to a person in Germany with a name of German origin. Distance did not affect donating money to climate protection or approving of mitigation policies. Our results provide evidence for the existence of a negative effect of distance to climate change consequences on the willingness to engage in low-cost mitigation actions. Investigating explanations for such an effect, we find that it can be attributed to the spatial rather than the social dimension of distance. Moreover, we find some cautious evidence that people with strong racist attitudes react differently to the distance manipulations, suggesting a form of environmental racism that could also reduce mitigation action in the case of climate change. [ABSTRACT FROM AUTHOR]

Strong public support is a prerequisite for ambitious and thus costly climate change mitigation policy, and strong public concern over climate change is a prerequisite for policy support. Why, then, do most public opinion surveys indicate rather high levels of concern and rather strong policy support, while de facto mitigation efforts in most countries remain far from ambitious? One possibility is that survey measures for public concern fail to fully reveal the true attitudes of citizens due to social desirability bias. In this paper, we implemented list-experiments in representative surveys in Germany and the United States (N = 3620 and 3640 respectively) to assess such potential bias. We find evidence that people systematically misreport, that is, understate their disbelief in human caused climate change. This misreporting is particularly strong amongst politically relevant subgroups. Individuals in the top 20% of the income distribution in the United States and supporters of conservative parties in Germany exhibit significantly higher climate change skepticism according to the list experiment, relative to conventional measures. While this does not definitively mean that climate skepticism is a widespread phenomenon in these countries, it does suggest that future research should reconsider how climate change concern is measured, and what subgroups of the population are more susceptible to misreporting and why. Our findings imply that public support for ambitious climate policy may be weaker than existing survey research suggests. [ABSTRACT FROM AUTHOR]

Proliferative kidney disease (PKD) caused by the myxozoan parasite Tetracapsuloides bryosalmonae is an emerging salmonid disease implicated in recent declines in salmonid populations. Laboratory experiments have shown that the clinical symptoms of PKD exacerbate with increasing temperature. However, empirical evidence for a relationship between climate change and PKD driven declines in wild salmonid stocks is scarce.The current study uses both empirical data and ecological niche modelling to extrapolate future changes in temperature and precipitation on the spread of PKD in relation to changes in suitability of rivers for its primary bryozoan and secondary salmonid hosts.A 20‐year dataset on brown trout density using standardised method shows a decline of more than 50% in the population of the river Wutach, south‐western Germany at 536–755 m elevation. The decline coincides with higher prevalence of PKD. This decline was temperature related and driven by reduced local survival of parr to yearlings. Kidney hyperplasia was highest at low elevations and correlated negatively with trout density.Niche models based on state‐wide data show strong overlap in the areas suitable for T. bryosalmonae and its primary bryozoan hosts, and a strong link with temperature. Projections based on moderate to high emission‐case climate change scenarios predict a 50%–82% decrease in the area suitable for salmonids within this century, linked to PKD.The empirical data identify temperature‐mediated PKD as the underlying cause of the population decline. This relationship was corroborated by the niche modelling results. The highest losses are expected in projected salmonid suitable areas where salmonid habitats currently overlap with areas suitable for T. bryosalmonae.With ongoing climate change, both current and future populations are at severe risk to T. bryosalmonae and its associated disease PKD. Conservation efforts of salmonid stocks are dependent on climate mitigation and measures to help salmonids adapt to the disease. [ABSTRACT FROM AUTHOR]

Forest management affects carbon sequestration (mitigation) and resilience of forest ecosystems (adaptation) under climate change. Therefore, the efforts to integrate these two approaches have been made by the political arrangements to seek the synergy effects and deal with trade-offs. To study the state of the art linkages and forest policies to realize both adaptation and mitigation, we systematically review the literature highlighting the topic (136 publications) and outline two different approaches from Germany and Japan as countries with substantial forest resources and high influences on international forest policies and wood trade. We identify three linkages: (1) an ecosystem (based) approach assuming that a resilient ecosystem (adaptation), has high potential as a carbon sink (mitigation), (2) a sustainable forest management (SFM) aiming for enhancing forests' resilience and carbon sink potential simultaneously, and (3) a cross-sectoral approach generating synergies among multiple sectors of agriculture, forestry, urban design, and nature conservation. We find that a significant objective is still SFM for sustaining the forest area andwood production, where SFM examples in Germany and Japan exemplify contributions to carbon sinks and ongoing disaster risk management, respectively. Overall, the current differentiated objectives of SFM do not underpin the twofold approach and their synergy effects. [ABSTRACT FROM AUTHOR]

Company cars have received considerable attention because of their partial tax-exemption and the changes in travel behaviour they stimulate, including car model choices, distances driven, and car ownership patterns. This paper is the first to present evidence on actual transport behaviour change, based on mobility and fuel diaries, and comparing a sample of 624 company cars and 9328 private cars in Germany. Analysis confirms that company cars belong to the more heavily motorized car segments (with an average 97 kW, as opposed to 79 kW of private cars), and are driven more than private cars (24,672 km per year, compared to 12,828 km per year for private cars). Company car benefits also increase average household vehicle numbers by 25%. Results show that it is imperative to distinguish company cars of company owners relative to those driven by employees, as negative externalities increase significantly where company cars are used by the latter. Abolishing company car benefits could significantly reduce emissions from passenger road transport and stimulate change in the country's automotive industries towards a lower-carbon path. As Germany is not currently on track to meet its climate mitigation targets, this would be a timely policy shift. Key policy insights Company car benefits increase transport demand, car ownership, and average vehicle fleet engine power. These effects are particularly relevant for employees. Company cars have, in spite of their larger size and greater engine power, a (modestly) better fuel economy than private cars, possibly because they represent more recent and hence more efficient car models. A policy focus on vehicle fuel efficiency improvements will fail to reduce the German car fleet's CO2 emissions to a sustainable level. Abolishing company car benefits could yield a significant reduction in GHG emissions from passenger road transport. Company car subsidies are an out-dated mode of support for the fossil-fuel based automotive industry. [ABSTRACT FROM AUTHOR]

Climate models project higher temperatures and a substantial net water deficit during the summer months over Germany until the end of the 21st century. The agricultural sector is particularly vulnerable to changing weather and climate conditions. In this study, we examine the role of irrigation for potato yields as a climate change adaptation measure in Northeast Lower Saxony (Germany). The region represents the largest irrigated area in Germany and is one of the main growing areas of potatoes. We develop a statistical multivariate regression model to investigate whether regional climate and irrigation data at the monthly and county level are suitable to describe potato yield variability from 1978 to 2018. Irrigation is estimated based on the climatic water balance and crop water demand. These estimates are calibrated against irrigation data from local agencies to account for realistic monthly water withdrawals. We analyze future yield changes based on climate model projections for the 21st century and different irrigation scenarios. We find that the potato yield will decrease significantly by 18% on average until 2050 with climate projection uncertainty of ±6.4% under the high emission scenario RCP 8.5 and without irrigation. Irrigation at current levels could compensate for about 54% of these yield losses. Doubling the amount of irrigation minimizes yield losses by as much as 80%. Under the low (middle) emission scenario RCP 2.6 (RCP 4.5), potato yield are projected to decrease moderately by 4.5% ± 3.4% (5.4% ± 2.8%) with irrigation at current levels. We show that the yield losses mainly originate from higher temperatures during the summer. Our analysis indicates that the capacity of irrigation to minimize yield losses is limited. Strengthening climate change mitigation efforts may be more effective in preventing yield losses. However, the effect of elevated CO 2 might buffer the high yield losses, especially in RCP 8.5. The studies supports farmers and decision makers in assessing future risks in potato yields. It can guide policymakers in allocating economic resources to cope with climate change. [Display omitted] • Potato yields in Germany will decrease sharply under climate change for RCP8.5. • Irrigation at current levels mitigates about half of the yield losses. • Irrigation potential is limited because it can not buffer high temperatures. • Climate change mitigation and other adaption actions need to complement irrigation. • The effect of elevated CO2 might buffer high yield losses, especially in RCP8.5. [ABSTRACT FROM AUTHOR]

Many studies have analysed the environmental impact of vegan, vegetarian, or reduced meat diets. To date, literature has not evaluated how diet shifts affect environmental impacts by utilising portfolios which reflect personal nutrition preferences. Further, changing diets could alter the available land for non-food uses. This paper defines novel diet portfolios to outline alternative diet transitions and choices within the population and finds their effect on greenhouse gas (GHG) emissions, primary energy use, and land use in Germany. The aim of this study is to capture how these diet shifts affect land availability and increase the options for land-based climate change mitigation strategies. To do so, a contextualisation is made to compare the use of freed-up land for afforestation or biomethane production (with and without carbon capture and storage). The investigated diet portfolios lead to a reduction of the investigated impacts (GHG emissions: 7–67%; energy use: 5–46%; land use: 6–64%). Additionally, afforestation of freed-up land from each diet portfolio leads to further emission removals of 4–37%. In comparison, using the land to produce energy crops for biomethane production could lead to 2–23% further CO2-eq emission reductions when replacing fossil methane. If biomethane production is paired with carbon capture and storage, emission abatement is increased to 3–34%. This research indicates various short-term pathways to reduce GHG emissions with portfolio diet shifts. Utilising freed-up land for climate change mitigation strategies could prove essential to meet climate targets, but trade-offs with, e.g. biodiversity and ecosystem services exist and should be considered. • Diet portfolios are used to represent realistic population diets. • Diet portfolios include a mixture of 12 different diets. • GHG emissions decrease by 67% if the population adopts a Vegan diet. • Afforestation removes almost double the emissions compared to biomethane. • BECCS has similar GHG abatement to afforestation. [ABSTRACT FROM AUTHOR]

• Climate impact analysis of air transport from Germany. • Scenario dependent forecast of passenger flights from Germany. • Scenario dependent forecast of specific emissions by traffic regions. • Focus on both CO 2 and NO x emissions. • Forecast of climate impact effects for three scenarios up to the year 2100. Transport is considered to be a major contributor to emissions, resulting in a deterioration of local air quality and contributing to global climate change. The present paper focuses on how passenger flights departing from German airports contribute to global climate change. We describe in detail, how traffic forecasts for three scenarios entitled Reference, Free Play and Regulated Shift have been developed and how the resultant emissions have been quantified. Subsequently, we applied a climate model, providing insights into the very long-term climate effects under different assumptions on emissions up to the year 2100. The modelling framework shows that the development of emissions results from complex interactions of demand development and supply decisions, which highly influence the climate impact. With this paper, we show that an integrated, multi-disciplinary analysis can create valuable indicators and advice for transport policy decisions. [ABSTRACT FROM AUTHOR]